Don’t Blur the Message on Cancer Screening

This week the USPSTF renewed its position on ovarian cancer screening. The panel reminded the public that there’s no value in doing blood tests, like measuring the CEA, or having sonograms to evaluate healthy-feeling women for the possibility of ovarian cancer. One problem with the CEA measurement is that it goes up in various conditions; it’s not a specific test. Similarly, abdominal ultrasounds tend to pick up all kinds of blobby images that are rarely ovarian tumors. More often than not, ovarian cancer screening tests lead women to undergo more tests, such as CT scans and even surgery, without any benefit. The CEA tests and ultrasounds rarely “catch” ovarian tumors in an early stage.

This information on the lack of effective ovarian cancer screening methods is hardly news. What I hope is that this week’s headlines and editorials don’t add to the blurriness of the public’s perception of cancer screening – that people might think it’s a bad thing all around. The details matter. For some cancers, screening the general population – if it’s done right – can save lives and dollars. That’s because for most tumor types, treating advanced, metastatic disease is costlier than treatment of early-stage, curable tumors.

A few words on other cancers and screening –

Prostate cancer screening by PSA testing has never been shown to save lives. Because prostate cancer is unusual in young men and occurs commonly in elderly men, and in those cases tends to be slow-growing, screening’s potential – even if it were safe and effective – to save men’s life-years is limited. What’s different, also – and I think this is where some journalists get the story wrong by omission – is that early treatment of prostate cancer is rarely beneficial. By contrast, early treatment of breast cancer is often life-saving.

Lung cancer screening may be helpful in people at high risk, such as smoking, but one could argue that the CT scans used in those studies – which involve more radiation exposure than do mammograms, besides that they’re more costly – need a higher threshold of benefit to justify their use.

Colon cancer screening has been shown to save lives. For this tumor type, I think the issue is whether it’s worth doing colonoscopy in everyone over the age of 50, periodically, or better to test everyone for tiny amounts of blood (or, in the future, cancerous DNA markers) in the stool. Checking for occult blood in stood samples is a simple and perfectly safe method of getting a little bit of information about the probability of someone having a polyp or frank malignancy in the gut. If people who want to be screened for colon cancer would reliably take a sampling, it’s possible they might safely skip colonoscopy if there’s no evidence for bleeding or other signs of disease.

As for cervical cancer screening, that has definitely been an advance. Pap smears and other liquid cytology methods, now, perhaps HPV testing, have successfully countered this disease. Years ago, women would present, typically in their 30s, 40s or 50s, with large cancers pushing into the body of the uterus and lower abdomen. These were rarely curable. Rather than a scrape, or slightly bigger procedure in a gynecologist’s office, the women needed hysterectomies and radiation to the pelvis, which caused problems down the road if they were lucky and survived. In communities where young women get gynecological care now, we rarely see advanced cases of cervical cancer. For this disease, the question now is in fine-tuning the frequency of screening and understanding how HPV tests can inform or supplement the Pap smear.

As for mammography in breast cancer screening, please don’t get me wrong. I am not fixed in my position that it’s worthwhile and should be performed every other year in most women over the age of 40 until they reach the age of 70 or so, depending on their wishes and overall health. Rather, I acknowledge it’s far from a perfect screening tool, and I genuinely hope that in the future we’ll prevent breast cancer entirely or at least find a better, safer way to detect it early on. But until that happens, for the time being, mammography is a well-established, routine procedure that is the best we’ve got to prevent tens of thousands of middle-aged women from dying every year in the U.S. from metastatic BC.

I generally ascribe to the “less is more” school of medicine. But that doesn’t mean we should ignore early-stage breast tumors, especially when they occur in young-ish women. Rather, it means that we should treat what cancers we do find carefully and conservatively, with the least therapy needed to raise a woman’s chances of leading a normal, healthy and full life.

All for now,


A Closer Look at the Details on Mammography, in Between the Lines

Recently I wrote a review of Between the Lines, a helpful handbook on bio-medical statistics authored by an acquaintance and colleague, Dr. Marya Zilberberg. In that post, I mentioned my concern about some of the assumptions and statements on mammography. One thing I liked the book, abstractly, is the author’s efforts to streamline the discussion so that the reader can follow the concepts. But simplification and rounding numbers, “for ease of presentation” (p. 29) can mess up facts, significantly in ways that some primary care doctors and journalists might not appreciate. And so I offer what I hope is a clarification, or at least an extension of my colleague’s work, for purposes of helping women understand the potential benefits and risks of mammography.

In the section on mammography (pp. 28-31), the author rounds down the incidence of breast cancer in women between the ages of 40 and 50 years, from “1 in 70” (1.43%) to “1 in 100” (1%). As any marketing professional might remind us, this small change represents a 30% drop (0.43/1.43) in the rate of breast cancer in women of that age group. This difference – of 30%, or 43%, depending on how you look at it – will factor into any calculation of the false positive (FP) rate and the positive predictive value (PPV) of the test.

For women ages 40-49 Have breast cancer Don’t have breast cancer
If estimate 1 in 100, 1.0 % 100 9,900
If estimate 1 in 70, 1.43 % 143 9,857

Keep in mind that these same, proportional difference would apply to any BC screening considerations – in terms of the number of women affected, the potential benefits and costs, for the 22,996,493 women between the ages of 40 and 49 counted in the 2010 U.S. Census,

My colleague estimates, fairly for this younger age group of women (who are relatively disposed to fast-growing tumors), that the screening technology (mammography) only picks up 80% of cases; 20% go undetected. In other words – the test is 80% sensitive; the false negative, FN, rate is 20%. In this same section, she considers that the FP rate as 10%. Let’s accept this (unacceptably high) FP rate for now, for the sake of discussion.

As considered in Between the Lines:

If FP rate is 10%, prevalence 1 in 100 Really have BC Don’t have BC Total
Mammography + 80 990 1,070
Mammography – 20 8,910 8,930
Total 100 9,900 10,000

But the above numbers aren’t valid, because the disease affects over 1 in 70 women in this age bracket. Here’s the same table with a prevalence of 1 in 70 women with BC:

If FP rate is 10%, prevalence 1 in 70 Really have BC Don’t have BC Total
Mammography + 114 986 1,100
Mammography – 29 8,871 8,900
Total 143 9,857 10,000

In this closer approximation to reality, the number of true positives is 114, and false positives 986, among 1,100 abnormal screening results. Now, the PPV of an abnormal mammogram is 114/ (114+986) = 10.4%. So the main statistical point – apart from the particulars of this discussion –  is that a seemingly slight rounding down can have a big impact on a test’s calculated and perceived value. By adjusting the BC rate to its prevalence of approximately 1 in 70 women between 40 and 49 years, we’ve raised the PPV from 7.5% to 10.4%.

Here I must admit that I, too, have rounded, although I did so conservatively very slightly. I adopted a 1 in 70 approximation (1.43%) instead of 1 in 69 (1.45%), as indicated on the NCI website. If we repeat the table and figures using a 1 in 69 or 1.45% prevalence rate and 6% FPS, the PPV rises a tad, to 10.5%.

Now, we might insert a different perspective: What if the false positive rate were 6%, as has been observed among sub-specialist radiologists who work mainly in breast cancer screening?

If FP rate is 6%, prevalence 1 in 70 Really have BC Don’t have BC Total
Mammography + 114 591 705
Mammography – 29 9266 9,295
Total 143 9,857 10,000

As you can see, if we use a FP rate of 6% in our calculations, the total number of FPs drops to 591 among 10,000 women screened. In this better-case scenario, the PPV of the test would = 114/ (114+591) =16%. Still, that’s not great – and I’d argue that public health officials, insurers and patients should be pushing for FP rates closer to 2 or 3% – but that’s irrelevant to my colleague’s point and her generally instructive work.

My second concern has to do with language, and making the consequences of false positives seem worse than they really are. On page 29, the author writes: “ So, going back to the 10,000 women being screened, of 9,900 who do NOT have cancer… 10%, or 990 individuals will still be diagnosed as having cancer.” The fact is, the overwhelming majority of women with positive mammograms won’t receive a cancer diagnosis. Rather, they’ll be told they have “an abnormal result, or a finding that suggests the possibility of cancer and needs further evaluation,” or something along those lines. It would be unusual in practice to jump from a positive mammogram straight to a breast cancer diagnosis. There are steps between, and every patient and journalist should be aware of those.

Finally, if I were to write what I really think, apart from and beyond Between the Lines – I’d suggest the FP rate should be no higher than 2 or 3% in 2012. This is entirely feasible using extant technology, if we were to change just two aspects of mammography practice in the U.S. First, require that all mammograms be performed by breast radiologists who get extra training and focus in their daily work almost exclusively on breast imaging. Second, make sonograms – which, together with mammograms, enhance the specificity of BC screening in women with dense breasts– universally available to supplement the radiologists’ evaluations of abnormal mammograms and dense breasts in younger women.

By implementing these two changes, essentially supporting the practice of sub-specialists in breast radiology, we could significantly lower the FP rate in breast cancer screening. The “costs” of those remaining FPs could be minimized by judicious use of sonograms, needle biopsies and other measures to reduce unnecessary surgery and over-treatment. Over the long haul, we need to educate doctors not to over-treat early stage disease, but that goes far beyond this post and any one woman’s analysis of mammography’s effectiveness.

All for now,

NEJM Publishes New Review on Breast Cancer Screening

With little fanfare, the NEJM published a feature on breast cancer screening in its Sept 15 issue. The article, like other “vignettes” in the Journal, opens with a clinical scenario. This time, it’s a 42 year old woman who is considering first-time mammography.

The author, Dr. Ellen Warner, an oncologist at the University of Toronto, takes opportunity to review updated evidence and recommendations for screening women at average risk for the disease. She outlines the problem:

Worldwide, breast cancer is now the most common cancer diagnosed in women and is the leading cause of deaths from cancer among women, with approximately 1.3 million new cases and an estimated 458,000 deaths reported in 2008.(1)

On screening:

The decision to screen either a particular population or a specific patient for a disease involves weighing benefits against costs. In the case of breast-cancer screening, the most important benefits are a reduction in the risk of death and the number of life-years gained….

She breaks down the data for mammography by age groups:

For women between the ages of 50 to 69 the evidence is clear, she says. For those over 70, there are little data to support breast cancer screening. There’s a consensus that screening isn’t appropriate for women with serious coexisting illnesses and a life expectancy of less than 5-10 years.

For those between the ages of 40-49, Warner challenges the revised 2009 USPSTF recommendations on several counts. She critiques those authors’ weighting of data from the Age trial of 161,000 women, emphasizing the use of an antiquated (single view) mammography technique and flawed statistics. She considers:

…However, this change in remains highly controversial,22, 23 especially because of the greater number of years of life expectancy gained from preventing death from breast cancer in younger women. According to statistical modeling,19 screening initiated at the age of 40 years rather than 50 years would avert one additional death from breast cancer per 1000 women screened, resulting in 33 life-years gained.”

What I like about Warner’s analysis, besides its extreme attention to details in the data, is that she’s not afraid to, at least implicitly, assign value to a procedure that impacts a young person’s life expectancy relative to that of an older person.

She goes on to consider digital mammography and the Digital Imaging Screening Trial (DMIST [NCT00008346]) results. For women under 50 years, digital mammography was significantly more sensitive than film (78% vs. 51%).

The article is long and detailed; I recommend the full read including some helpful tables, with references to the major studies, and charts.

In concluding, the author, who admits receiving grant support from Amersham Health (a GE subsidiary), consulting fees from Bayer and lecture fees from AstraZeneca, returns to the hypothetical patient, and what might be said to a woman in her 40s who lacks an outstanding risk (such as a genetic disposition or strong family history):

…Mammography screening every 2 years will find two out of every three cancers in women her age, reduce her risk of death from breast cancer by 15%. There’s about a 40% chance that further imaging (such as a sonogram) will be recommended, and a 3% chance for biopsy with a benign finding….

In my opinion (ES) this is key – that the chances of a false positive leading to biopsy are only 3% for a woman in her 40s. If those biopsies are done in the radiology suite with a core needle, every 2 years for women of average risk, the costs of false positives can be minimized.

Mammography Update!

This week I’ve come across a few articles and varied blog posts on screening mammography. The impetus for rehashing the topic is a new set of guidelines issued by the American College of Obstetricians and Gynecologists. That group of women’s health providers now advises that most women get annual mammograms starting at age 40.

Why every year? I have no idea. To the best of my knowledge, there are no data to support that annual mammograms are cost-effective or life-saving for women in any age bracket at normal risk for BC.

Pertinent also, is a recent paper* in the Annals of Internal Medicine supporting a personalized approach to BC screening and mammography for women over the age of 40, and an editorial* to go with it.

“Talk to your doctor,” is the point for patients. (Women’s breasts are not all the same.)

“Talk with your patient,” is the point for doctors: Consider your patient’s breast density, family health history and personal preferences. Great idea!

We need an Annals paper to tell us this?

My personal view, synthesizing all the medical literature of which I’m aware, and taking account all of my prior experiences as a practicing oncologist, and not forgetting I’m a woman, now 50, who had an early-stage breast cancer discovered by a radiologist – and this is not medical advice – is as follows:

For women of normal risk, such as without a strong family history or a prior cancer:

1. Start with a baseline, digital mammogram at age 40. The image should be digital first, because this kind of technology is better for visualizing dense breast tissue which is more common in pre-menopausal, younger women and second, because digital images can more easily be shared with another doctor, for a second or more expert opinion if necessary.

2. Get mammograms every other year, unless there’s a significant abnormality that requires follow-up sooner. Until what age? Hard to say. (A complex topic… hold that thought for another post.)

3. Supplement mammography every other year with monthly self-examination of the breast. This inexpensive method of feeling one’s own breasts, regularly and methodically, has not been shown to save lives in randomized clinical trials. But I am convinced that if it’s done right – when a gynecologist, PCP, internist or other caregiver takes the time to teach her patients how to do the breast self-exam properly  – as I used to instruct my patients in the clinic, women can help themselves to catch breast tumors early.

4. Mammograms should be done, exclusively, by appropriately-trained radiologists who spend the bulk of their time reading mammograms, performing sonograms of the breast and taking occasional biopsies, as appropriate. (Sorry, general radiologists, but that’s how it is. Would you want your mother’s breast image examined by a radiologist who also reads hip films and MRIs of the brain at the hospital where she works?) The rate of false positives is lower when mammograms are performed by specialized “breast” radiologists.

5. Take advantage of the fact that mammography centers have been regulated for nearly two decades by the FDA. Be sure that the place where you get your mammogram is MQSA-accredited.

All for now –


*subscription required for full text

Breast Cancer Rate in the U.S. is No Longer Declining

A worrisome report on breast cancer trends in the U.S. appeared on-line today, ahead of print in an AACR journal, Cancer Epidemiology, Biomarkers & Prevention.

The analysis, based on the NCI’s SEER data from 2000 – 2007, shows that the incidence of breast cancer in the U.S. is no longer declining. (A drop after 2002 in BC incidence is generally attributed to an abrupt reduction in HRT around that time.)

Since 2003 the overall BC rate has been steady overall, with a few exceptions:

The incidence of BC in non-Hispanic white women ages 60-69 rose by 4.8% in this period. “It remains to be seen if this trend will continue,” according to the study authors.

Among white women ages 40-49 rates of estrogen receptor (ER) positive (ER+) breast cancer significantly increased by an average of 2.7% per year during this period. In contrast, the rate of ER- breast tumors decreased, overall, although the trends were statistically significant only for women ages 40-49 and 60-69.

Apart from women younger than 40, overall BC rates and ER+ case rates were highest among non-Hispanic white women, followed by non-Hispanic black and Hispanic women. Among black women ages 40-49, the incidence of ER+ BC increased (5.2% per year) during 2003-2007, and there were non-significant, recent increases in ER+ BC among older black women.

Of note, in contrast to the pattern for ER+ breast cancer, non-Hispanic black women have the highest rates of ER- breast cancer in every age group. (These ER- cases would include triple negative BC.)

Sorry for the jargon, readers – I hadn’t planned to post now. But I think this information warrants attention.

This matters for a number of reasons. First, it’s bad news in terms of women’s health, plain and simple. Second, these numbers relate to the mammography math, which has been on my mind lately. The point is that if more women between the ages of 40 and 49 are developing ER+ (read: most treatable) tumors, this would influence the net benefit of cancer screening in that age group.

And please don’t misread me here: This is not an academic argument I want to win. Rather, I wish the incidence of breast cancer were declining. And I wish, even more, that so many middle-aged women I know personally weren’t affected by this devastating illness.

Radiologists’ Experience Matters in Mammography Outcomes

There’s a new study out on mammography with important implications for breast cancer screening. The main result is that when radiologists review more mammograms per year, the rate of false positives declines.

The stated purpose of the research,* published in the journal Radiology, was to see how radiologists’ interpretive volume – essentially the number of mammograms read per year – affects their performance in breast cancer screening.  The investigators collected data from six registries participating in the NCI’s Breast Cancer Surveillance Consortium, involving 120 radiologists who interpreted 783,965 screening mammograms from 2002 to 2006. So it was a big study, at least in terms of the number of images and outcomes assessed.

First – and before reaching any conclusions – the variance among seasoned radiologists’ everyday experience reading mammograms is striking. From the paper:

…We studied 120 radiologists with a median age of 54 years (range, 37–74 years); most worked full time (75%), had 20 or more years of experience (53%), and had no fellowship training in breast imaging (92%). Time spent in breast imaging varied, with 26% of radiologists working less than 20% and 33% working 80%–100% of their time in breast imaging. Most (61%) interpreted 1000–2999 mammograms annually, with 9% interpreting 5000 or more mammograms.

So they’re looking at a diverse bunch of radiologists reading mammograms, as young as 37 and as old as 74, most with no extra training in the subspecialty. The fraction of work effort spent on breast imaging –presumably mammography, sonos and MRIs – ranged from a quarter of the group (26%) who spend less than a fifth of their time on it and a third (33%) who spend almost all of their time on breast imaging studies.

The investigators summarize their findings in the abstract:

The mean false-positive rate was 9.1% (95% CI: 8.1%, 10.1%), with rates significantly higher for radiologists who had the lowest total (P = .008) and screening (P = .015) volumes. Radiologists with low diagnostic volume (P = .004 and P = .008) and a greater screening focus (P = .003 and P = .002) had significantly lower false-positive and cancer detection rates, respectively. Median invasive tumor size and proportion of cancers detected at early stages did not vary by volume.

This means is that radiologists who review more mammograms are better at reading them correctly. The main difference is that they are less likely to call a false positive. Their work is otherwise comparable, mainly in terms of cancers identified.**

Why this matters is because the costs of false positives – emotional (which I have argued shouldn’t matter so much), physical (surgery, complications of surgery, scars) and financial (costs of biopsies and surgery) are said to be the main problem with breast cancer screening by mammography. If we can reduce the false positive rate, BC screening becomes more efficient and safer.

Time provides the only major press coverage I found on this study, and suggests the findings may be counter-intuitive. I guess the notion is that radiologists might tire of reading so many films, or that a higher volume of work is inherently detrimental.

But I wasn’t at all surprised, nor do I find the results counter-intuitive: the more time a medical specialist spends doing the same sort of work – say examining blood cells under the microscope, as I used to do, routinely – the more likely that doctor will know the difference between a benign variant and a likely sign of malignancy.

Finally, the authors point to the potential problem of inaccessibility of specialized radiologists – an argument against greater requirements, in terms of the number of mammograms a radiologist needs to read per year to be deemed qualified by the FDA and MQSA. The point is that in some rural areas, women wouldn’t have access to mammography if there’s more stringency on radiologists’ volume. But I don’t see this accessibility problem as a valid issue. If the images were all digital, the doctor’s location shouldn’t matter at all.


*The work, put forth by the Group Health Research Institute and involving a broad range or investigators including biostatisticians, public health specialists, radiologists from institutions across the U.S., received significant funding from the ACS,  the Longaberger Company’s Horizon of Hope Campaign, the Breast Cancer Stamp Fund, the Agency for Healthcare Research and Quality (AHRQ) and the NCI.

**I recommend a read of the full paper and in particular the discussion section, if you can access it through a library or elsewhere. It’s fairly long, and includes some nuanced findings I could not fully cover here.

New Numbers Should Factor Into the Mammography Equation

On Friday the New York Times reported that surgeons are performing far too many open breast biopsies to evaluate abnormal mammogram results. A new American Journal of Surgery article analyzed data for 172,342 outpatient breast biopsies in the state of Florida. The main finding is that between 2003 and 2008, surgeons performed open biopsies in an operating room – as opposed to less invasive, safer biopsies with needles – in 30 percent of women with abnormal breast images.

I was truly surprised by this should-be outdated statistic, which further tips the mammography math equation in favor or screening. These numbers matter, and should be based in modern medical practice.

When the Annals of Internal Medicine published the since-adjusted recommendations for breast cancer screening by mammography in November 2009, the stated considerations were not about dollars and cents – which were incalculable – but about the number of women needed to be screened to save one life, and the incidence of false positives which cause harm – worrying, needless biopsies, complications of procedures, overtreatment, etc.

In the context of the health care reform discussion, and considering our country’s out-of-the-sky-and-rising medical bills, some (hopefully) well-intentioned economists heard about those trumped-up mammography papers and concluded that we shouldn’t screen women under 50 for breast cancer because it’s harmful and, what’s more, we can’t keep paying for this sort of care because it’s not evidence-based.

Those conclusions were flawed, though, because the data in those papers were old, as I’ve written previously, and didn’t include studies of digital mammography – which is better for detecting cancer in younger women who tend to have denser breast tissue. In December 2009, I noted that it was unreasonable to consider the costs of open needle biopsies in O.R.’s in any calculation of the harms of mammography, as had the Annals authors, because those kinds of procedures are outdated, or so I thought they were.

It turns out I’ve been living, still, in an academic medical enclave. According to the Timescoverage by Denise Grady:

The reason for the overuse of open biopsies is not known. Researchers say the problem may occur because not all doctors keep up with medical advances and guidelines. But they also say that some surgeons keep doing open biopsies because needle biopsies are usually performed by radiologists. The surgeon would have to refer the patient to a radiologist, and lose the biopsy fee…

The Times article suggests this pattern of over-doing open-biopsies, as documented in Florida, likely reflects national tendencies, including variation among different types of practices – academic, hospital-based, etc.

According to the article published in the American Journal of Surgery, the costs of a core needle biopsy using imaging guidance is around $5,000, or – if a vacuum biopsy device is used, around $6,000; the costs of an open procedure in the O.R. run in the range of $11,000 or more. The Times article indicates that doctors’ fees for a needle procedure range from $750 to $1500, and for an open, surgical biopsy from $1,500 to $2,500. For a ballpark estimate of the cost difference, say a core needle procedure is $5,500 + $1,000 for the doctor’s fees – that’s ~$6,500; a surgical procedure is $11,000 + $2,000 for the surgeon’s fees – that’s $13,000, an easy double.

So let’s say, for the sake of future calculations on mammography, that 10 percent of breast biopsies really do need to take place in the O.R. (which is a generous over-estimate, I think it should be 5 percent or fewer). But if 10 percent need be in the O.R.: then 20 percent of breast biopsies in the U.S. each year – said in the surgery paper to be 1.6 million per year in the U.S. – are being performed through an unnecessary, costlier technique.

An extra $6,500 x 20 percent of 1.6 million procedures = $2.08 billion additional costs, per year.

Let’s call it an even $2.1 billion, or $2 billion, we should shave off the collective amount we spend on mammography and appropriate follow-up. The last digit doesn’t matter; these are huge numbers. No wonder the Times put this story on the front page.

These results should be factored into any proper calculation of costs in breast cancer screening. Now add (or better, subtract) the implications of the findings of two weeks ago – that full lymph node dissection is usually not necessary in women, even if the sentinel node is found to be positive at the time of definitive surgery for what turns out to be a cancer.

What needs be reassessed by public health specialists and economists who weigh in on these issues – and please help me out here, Task Force members and Dartmouth friends, if you would, because your input affects public thinking and, ultimately, policy – are the legitimate costs of screening (every other year, as opposed to annually), doing needle biopsy procedures (instead of open biopsies) and reducing the costs and long-term complications of surgery by eliminating routine lymph node dissection from the equation.

And then we should assess those numbers relative to the costs of treating a woman with metastatic breast cancer, which still has not yet been determined.

Five Ways to Improve the Quality and Success of Breast Cancer Screening by Mammography

Here are some ideas on how we might reduce the incidence of metastatic breast cancer, by making high-quality mammography available to all women:

1. Modernize all breast imaging facilities. All should comply with the Mammography Quality Standards Act and Program (MQSAP) of 1992.

2. Ensure that radiologists, technicians and other BC screening workers are up to date: requirements for continuing medical education in an academic, unbiased (non-pharma or biotech setting), should be strict. We depend on practitioners’ current knowledge of breast imaging methods, breast biopsy techniques, hygiene, information technology (IT) and patient privacy laws.

3. Implement digital mammography in all screening facilities; Digital images allow radiologists to adjust the contrast, magnify or otherwise highlight areas of concern, to better analyze potential lesions without subjecting patients to extra x-rays.

4. Supplement mammograms with sonograms of the breasts. These inexpensive tests can help radiologists discern cysts and other benign lesions from malignant tumors. In some situations, a radiologist inspecting a sonogram can spot a small solid abnormality that’s missed in a mammogram. In principle, this low-rad combo – of digital mammography and breast sonography – would increase sensitivity and specificity of breast cancer screening.

(5.) Consider transmitting digital images to breast screening centers, so that expert radiologists can review every woman’s films.

As Sue, a woman who’s had breast cancer told me last month: “You don’t want a radiologist who’s just looked at someone’s broken foot examining your mammogram.” She’s right: Expertise can make a huge difference in clinical outcomes.

Why It’s So Hard to Assess False Positives, and How We Might Reduce Them

It’s been nearly a year since we “learned” about the false positives issue, and still there’s hardly any data published on this much-maligned cost of breast cancer screening by mammography.

From the U.S. Preventive Services Task Force November 2009 paper in the Annals, on the lack of information on the incidence of  FP’s:

“Published data on false-positive and false-negative mammography results, additional imaging, and biopsies that reflect current practices in the United States are limited. The probability of a false-positive screening mammography result was estimated at 0.9% to 6.5% in a meta-analysis of studies of sensitivity and specificity of mammography published 10 years ago <ref. 38>. The cumulative risk for false-positive mammography results has been reported as 21% to 49% after 10 mammography examinations for women in general <39–41>, and up to 56% for women aged 40 to 49 years (41)

False positives happen in mammography when a woman has an abnormal result that looks like it might be breast cancer, but upon a further workup – which might involve another, more expert radiologist taking a look, or a sonogram, or an MRI, or even a breast biopsy, but in the end the problem turns out not to be breast cancer.

Why is it so hard to ascertain how often false positives occur?

1. The rate of false positive mammograms is, most likely, declining (i.e. the number is in flux).

Reduced errors would result from two factors: improved methods, such as by adaptation of digital mammography, and by more careful application of extant technology due to progressive compliance with the FDA’s Mammography Quality Standards Act and Program.

2. There’s no precise definition of what constitutes a false positive in mammography, and what isn’t. As I’ve suggested previously, finding a pre-malignant condition like LCIS or an early-stage malignancy like DCIS should not be “counted” as a false positive. If over-treatment occurs, that reflects an error in clinical decision-making rather than in mammography, per se.

3. The false positive rate varies among radiologists and medical centers. That’s because a radiologist who spends her days doing nothing but reading mammograms and breast sonograms will, overall, have a lower FP rate than a general radiologist who also handles hip fracture films and MRIs of the brain.

What are financial costs of false positives? I’m not aware of any new data on this.

How can we reduce the costs of false positives in mammography? My suggestions:

1. Radiologists should be well-trained and carefully-credentialed. As in surgery and other fields in medicine, the physician’s skills and experience affects the probable outcome.

2. Avoid doing breast biopsies in an operating room whenever possible. A fine needle aspirate or core needle biopsy, performed under local anesthesia, is almost always sufficient for diagnosis and less costly.

3. Thinking for the future: Maybe, one good application of Telemedicine would be in sharing digital mammography images, so that no matter where a woman lives, her test could be checked by a radiologist working in a central cancer center and who specializes in breast imaging.

4. Do the procedure every other year for women of average risk for breast cancer (rather than annually). Quite a few theoretical calculations of mammography costs “stack” the purported costs by assuming the procedure is done every year, but there’s no data to support such frequency.

In sum, there’s every reason to think the rate of false positives in screening mammography is falling and that costs from errors will diminish in the future.

Many, if not all, of the costs attributed to false positives will be reduced by advances in technology, better training of radiologists, and education of physicians (oncologists, surgeons, primary care physicians) who recommend the procedure and make decisions based on the results.

It’s Not About the Money

A recent NEJM article, Lessons from the Mammography Wars, opens with a quote from the 18th Century philosopher-economist Adam Smith:

People of the same trade seldom meet together . . . [without] the conversation end[ing] in a conspiracy against the public.

The Wealth of Nations (1776)

The opinion piece, published on Sept. 8, considers the controversy that surrounded last year’s U.S. Preventive Service Task Force recommendations for screening mammography in the context of broader issues. It contains some serious accusations:

“Advocates of breast-cancer screening, particularly breast radiologists, immediately took action, denouncing the panel’s statements as government rationing, suggesting that the panel members had ignored the medical evidence…

Ultimately, what’s incriminated is the self-interest of doctors:

“…Although it is true that individual medical providers care deeply about their patients, the guild of health care professionals — including their specialty societies — has a primary responsibility to promote its members’ interests. Now, self-interest is not in itself a bad thing; indeed, it is a force for productivity and efficiency in a well-functioning market. But it is a fool’s dream to expect the guild…to compete on true value when the opportunity to inflate perceived value is readily available.

OK, readers, so how do I recommend we resolve this thorny issue?

Physicians should be on salaries, set in such a way that their earnings aren’t based on the procedures they order or perform. For example, I don’t think a surgeon should earn more money if he or she performs a greater number of biopsies or mastectomies, as opposed to spending time examining and speaking with patients who are contemplating those procedures. I don’t think an oncologist should earn more money by ordering or administering more infusions of chemotherapy, as opposed to recommending a “wait and watch” type approach, palliative care, or giving pills that are effective in some malignancies.

If physicians’ potential profit motive clouds the mammography debate, as the authors contend, that doesn’t mean that mammography is ineffective. Rather it signifies that doctors and scientists should analyze data and make clinical decisions in the absence of financial or other conflicts of interest.

If patients could know that their doctors don’t have a vested interest in mammograms, or any other test or procedure they might prescribe, they’d trust them more. It’s for this reason, above all, that we should disconnect doctors’ decisions from economic gain.


Getting the Math on Mammograms

The latest news’ focus on the breast cancer screening madness is about money.

So let’s do the math:

First, for argument’s sake, let’s say the U.S. Preventive Services Task Force is right – that to save the life of one woman between the ages of 40 and 49, on average, you’d have to screen some 1903 additional women every year or so for a period of 10 years.

This is, admittedly, a huge assumption; the panel analyzed two decades’ worth of data, some unpublished, involving complex models applied to millions of data points (humans) amassed in imperfectly-collected data sets that vary in size, scope and accuracy.

Next, let’s say the cost of a mammogram is $150, around what Medicare pays (yet another assumption, but we need to keep this simple or we’ll never get a sense of what’s really at stake here).

So if 2000 women (I’m rounding up) undergo annual screening for 10 years, the bill would come to $300 thousand per year, for a total cost of $3 million over a decade.  If those same middle-aged women were to get their mammograms biannually (every other year), the cost would be roughly $1.5 million per life saved.

This, the so-called cost of screening mammography for women between the ages of 40 and 49 (let’s call it “X”), is all over the news in various calculations, some that get closer to the right answer than others.

But what’s the cost of caring for one 45 year old woman with metastatic breast cancer?

Let’s call that amount “Y.”

Even the heartless among us would admit that we need to subtract, X-Y, to determine the financial cost of breast cancer screening to save one middle-aged woman’s life.

An insurance executive might say it’s in the range of $400 thousand, or a million dollars, or maybe even two million, if the woman lives long enough to go in and out of the hospital over the course of five years, undergo multiple surgical procedures, have semi-permanent intravenous catheters inserted and removed, suffer infections from those requiring at-home multi-week courses of intravenous antibiotics, all of this besides, of course, receiving chemotherapy, radiation, hormone treatments, incalculably expensive antibody infusions and newer, targeted therapies, followed by hospice (hopefully) or ICU care in the end.

Quick answer: maybe it’s cost-effective, or nearly so, to do screening mammograms on asymptomatic women in their forties.

But consider –  if the expert panel’s numbers are off just a bit, by as little as one or two more lives saved per 1904 women screened, the insurers could make a profit!

By my calculation, if one additional woman at a cost of, say, $1 million, is saved among the screening group, the provider might break even.  And if three women in the group are saved by the procedure, the decision gets easier…

Now, imagine the technology has advanced, ever so slightly, that another four or five women are saved among the screening lot.

How could anyone, even with a profit motive, elect not to screen those 2000 women?

The truest answer, of course, is that the value of any one person’s life is inconceivably huge.  And that doesn’t even enter into the equation.

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