Why Medical Lessons?

By |December 31st, 2009

One of the things I liked best about practicing medicine is that I was constantly learning.

Making rounds at seven in the morning on an oncology floor would be a chore if you didn’t get to examine and think and figure out what’s happening to a man with leukemia whose platelets are dangerously low, or whose lymphoma is responding to treatment but can’t take anymore medicine because of an intense, burn-like rash. You’d have to look stuff up, sort among clues and discuss the case with the team and other physicians.

And then you’d get to talk to the patients and their families. In the teaching hospital where I worked as a clinical oncologist, you’d encounter a mix of folks from my east side neighborhood, Russian and Chinese and Spanish-speaking immigrants with homes in all parts of New York City, and a spectrum of visitors from countries like Cambodia, Pakistan and Ecuador. Each case offered a window into another family’s values and concerns.

Being a patient is an entirely different sort of experience except that, like being a doctor, it involves learning about medicine, problem-solving and meeting all kinds of individuals.

As a child with scoliosis – a curved spine – I discovered early that some therapies don’t work as you might hope or expect. I wore a back brace for 4 years, 23 hours each day, and it didn’t do the job. Then, my parents took me to consult with most of a dozen male orthopedists. Their crassness, frankness and sometimes kindness impressed me. I realized that like any other humans – whether they’re dictators or shopkeepers – doctors vary in their personalities.

Today I recall one young doctor who helped me, a resident at the Hospital for Joint Diseases. He came by my room early in the evening of December 31, 1974 because I needed a new intravenous (IV) catheter. By then I’d been in the hospital for weeks after spine surgery; there was hardly a vein left for heparin, a blood-thinner. It turned out the resident came from a town on Long Island not far from where I lived. He spoke openly, about his experiences in high school, as he calmly and patiently patted down my arms and hands and legs and feet until he found a spot for the IV. He got the line in, and I got my medication.

Just before midnight, Dick Clark was on TV for a “New Year’s Rockin’ Eve.” The resident, whose name I don’t recall, came by to see how I was doing. He stayed for perhaps 15 minutes, for what seemed like no reason other than to keep me company. We counted the seconds and watched the ball drop on a small black-and-white TV suspended by a hinged-metal arm over my hospital bed.

He was compassionate, and that made me feel better. What a difference he, one essentially unnamable young physician, made in my experience of that New Year’s eve in the hospital, and in my life and work.

Today, December 31, I think of him as I navigate my path as a patient and as a doctor. I’m still learning about medicine, every day in each new year.

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Looking Ahead on Breast Cancer Screening

By |December 31st, 2009

My plan is to move on after this post – too much is happening in medicine to dwell on the mammography issue longer, or at least for the time being.

So I’ll close on the 2009 screening controversy with a few comments and considerations for the future.

Breast cancer, along with lymphoma and a few other tumors, is one of the few malignancies that oncologists can treat effectively in the majority of cases – well enough that most women with the disease now live for an essentially normal lifespan. About the risks and costs of breast cancer screening, I think they’re exaggerated and misrepresented in the recent news.

My concerns are chiefly three – as outlined elsewhere and previously here:

1. The Task Force analyzed data that are decades old;

2. The updated recommendations don’t apply to digital mammography (a fact rarely mentioned in the press coverage);

3. Radiologists vary in training and skill.

My conclusion is that rather than ditching a life-saving procedure that’s imperfect, we should make sure that all doctors and radiology facilities are up to snuff.
——–
On the reputed risks of mammography, harms and costs stemming false positive test results –

The risks of mammography should be minimal if the FDA does its job regulating the procedure. Among women in their forties and fifties, the number of false positives in Category I (as outlined in my proposed classification) can be reduced by digital technology supplemented with sonograms, an inexpensive and safe procedure.

Clerical-type errors shouldn’t happen, as in all of healthcare. Put simply, the system needs be scrupulous.

False positives due to misunderstanding of results, as in Category 2, can be resolved by better education and more effective communication.

Regarding the costs of follow-up testing by sonograms, MRIs, and biopsies – the medical risks and financial costs can be minimized through more careful, besides current, evaluation of each method. Just this month, an article in the Annals of Internal Medicine described the value of core needle biopsy (by any of several methods) in evaluating breast lesions. This technology, in widespread use over the ten years, renders open biopsy – a procedure done in an operating room – obsolete; there’s no reason to consider operating room costs in assessing breast biopsies in 2010.

As for the risk of over-treatment, I think doctors and patients have a lot learn and discuss, carefully. My take on the news of the past season is that somehow there’s been a blurring of facts for different cancer types.

For decades, oncologists including me have recommended a “watchful waiting” approach for some elderly men who have prostate cancer. This sort of treatment, while often appropriate for a 75 or 85-year old man with a small prostate tumor, is irrelevant to the decisions facing a 45 year old woman with breast cancer, another disease entirely.

Going back to my definition of a false positive in mammography screening –

We need to distinguish between errors in the measurement (cancer or not) and errors in decisions that we – patients and doctors – make after upon detecting a premalignant or early-stage malignancy in a woman’s breast.

A finding of either DCIS or LCIS upon biopsy does not constitute a false positive result. Rather, it’s good medicine to identify these conditions, especially for a middle-aged woman who anticipates a meaningful half-life ahead. What goes wrong after the diagnosis, such as a rushed or ill-informed decision to treat only subtle pathology, is not a mistake from mammography.

Errors in over-treating small tumors, and all the physical and financial costs associated, should be attributed instead to a lack of knowledge regarding DCIS and LCIS. Our understanding of these conditions – the molecular and cellular pathology, the course over time if left untreated, and the effects of medication, surgery and other therapies – lags far behind what we know about most forms of breast cancer.

What I hope we can learn, through clinical trials over the next decade, is how best to treat low-grade conditions such as DCIS and LCIS. That way, the costs of over-treating those will not, come 2020, cloud what should be straightforward decisions on the diagnosis and treatment of breast cancer in relatively young women.

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Proposed Model for Evaluating False Positives in Screening Mammography

By |December 30th, 2009

First, a definition* –

False positives happen in screening mammography when the images suggest the presence of a malignancy in a woman who doesn’t have cancer in her breast.

Here’s my proposed model –

Categories of False Positives in Screening Mammograms

False positives can arise during any of three conceptual segments of the testing process:

1. False positives occur during the test itself.

This happens when a radiologist inspects a film or digital image and labels the result as abnormal, but no cancer is present. This sort of problem is interpretive.

A common scenario goes like this – a spot in a mammography image suggests the presence of a possible tumor and the radiologist correctly notes that abnormality; later on, a doctor determines by sonogram, biopsy or another method that there is no malignancy in the breast.

(Other, uncommon problems in this category would include faulty equipment that reduce image quality, mislabeling or accidental switching of films; in principle, these kinds of errors should be non-events.)

2. False positives stem from miscommunication or misunderstanding of test results.

If a clerk accidentally phones the wrong patient and tells her she needs another procedure because the results of her mammogram are abnormal, that call might instigate an untoward, false positive result. If the error is corrected early on, so that affected woman worries only for a period of hours and has difficulty sleeping for one night, she might experience some psychological and/or small financial cost from the matter. But if the mistake isn’t caught until after she’s had a sonogram or MRI, and consulted with a surgeon or another physician, the costs grow.

False positives also arise if a patient misunderstands a test result. An essentially normal mammography report, for example, might mention the appearance of benign calcifications. Upon reading that result, a woman or her husband might become upset, somehow thinking that “benign” means “malignant.” This type of false positive error, based in poor communication and lack of knowledge, can indeed generate extra doctors’ visits, additional imaging tests and, rarely, biopsies to relieve misguided fears.

3. False positives derive from errors or misinterpretation of results upon follow-up testing.

This category of false positives in screening mammography is by far the biggest, hardest to define and most difficult to assess. It includes a range of errors and confusion that can arise after breast sonograms, MRIs and breast biopsies.

3a. false positives in subsequent breast imaging studies such as sonograms and MRIs:

Many women in their forties and early fifties are premenopausal; their estrogen-stimulated breasts tend to be denser than those of older women. Reading their mammograms may be less accurate than for postmenopausal women. For this reason, a doctor may recommend a sonogram or MRI to further evaluate or supplement the mammography images.

These two radiology procedures – sonograms and MRIs – differ and, for the most part, are beyond the scope of this discussion except that they, too, can generate false positive results. A sonogram, for instance, may reveal a worrisome lump that warrants biopsy. MRIs are more expensive and sensitive; these tend to pick up subtle breast irregularities including a relatively high proportion of benign breast lesions.

3b. false positives in breast biopsy:

A breast biopsy is an invasive procedure by which a piece of the gland is removed for examination under the microscope. Sometimes pathologists use newer instruments to evaluate the genetic, protein and other molecular features of cells in the biopsy specimen. Years ago, surgeons did the majority of breast biopsies. Now, skilled radiologists routinely do a smaller procedure, a core needle biopsy, using a local anesthetic and a small albeit sharp instrument that’s inserted through the skin into the breast. Some doctors do a simpler procedure, fine-needle aspiration, by which they remove cells or fluid from the breast using a small needle attached to a syringe.

In principle, a false positive biopsy result would occur only when a pathologist, a physician trained to examine tumors at the cellular and molecular levels, misreads a case, meaning that he or she reports that the cells appear cancerous when they’re not. Fortunately, this is not a frequent issue in breast cancer diagnosis and management.

The real issue about false positives – and what may be the heart of the issue in mammography screening – has to do with how pathologists describe and define some premalignant conditions and low-grade breast tumors. This concern extends well beyond the scope of this tentative outline, but a few key terms should facilitate future discussion:

Lobular Carcinoma in Situ (LCIS) is not considered a malignancy by most oncologists, but rather an abnormality of breast glands that can develop into breast cancer.

Ductal Carcinoma in Situ (DCIS) is a Stage 0 breast tumor – a tiny cancer of breast cells that have not penetrated through the cells lining the ducts of the breast gland.

Indolent or “slow” tumors – The idea is that some breast cancers grow so slowly there’s no need to find or treat these.**

——

*This definition warrants some discussion, to follow in a separate post.

**As a physician and trained oncologist, I am uncomfortable with the published notion of some breast tumors being “so slow” that they needn’t be found or evaluated. I include these tumors only for the sake of completeness regarding theoretical types of false positive results upon screening mammography, as there’s been considerable discussion of these indolent tumors in recent news.

Slow-growing breast tumors are quite rare in young women. In my view, their consideration has no bearing on the screening controversy at it pertains to women in their forties and fifties.

——

As outlined above, the first two categories of false positives seem relatively minor, in that they should be amenable to improvements in quality of mammography facilities and technology; the third category is huge and where lies the money, so to speak.

Clearly there’s more work ahead –

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A Bit More on False Positives, Dec 2009, Part 1

By |December 29th, 2009

The question of false positives in breast cancer screening – why and how these happen, how often these occur, and how much these cost, in physical, psychological and financial terms – remains a puzzle.

A few weeks ago the New York Times Magazine featured a piece on “Mammogram Math” under the heading “The Way We Live Now.” The author, a mathematics professor, argues that the risks and costs of mammography, though incalculable, outweigh the benefits. The paper printed the article along with a subtitle, “Why evidence-based medicine is actually right and scary” and later published three letters including one truncated response by me.

After a hiatus, I’ve rescanned the literature – just to be sure the question hasn’t been resolved in the past few weeks by a much-needed interdisciplinary team of health care policy experts, economists,  statisticians, surgeons, radiologists, oncologists, nurses and for good measure, perhaps a few breast cancer patients and survivors.

There’s little published progress to report, aside from more hype and theoretical numbers such as I offered in a November essay. So I’ve decided to take the analysis a step further by outlining a tentative framework for thinking about false positives in breast cancer screening.

In a separate post, I will outline a proposed outline for categorizing false positives as they relate to mammography. Why bother, you might ask – wouldn’t it be easier to drop the subject?

Make it go away,” sang Sheryl Crow on her radiation sessions.

Instead, I’ll answer as might a physician and board-certified oncologist who happens to be a BC survivor in her 40s:

To determine the damage done to women by screening mammography (as some claim and refer as evidence) we need establish how often false positives lead, in current practice, to additional procedures such as sonograms (fairly often, but the costs are relatively small), MRIs (less standard and more expensive), breast biopsies (scarier, slightly risky and more valued – how else can a pathologist determine if a woman with a breast lesion has cancer and, in the future, what type of therapy is best) or frankly inappropriate treatments such as chemotherapy for a non-cancerous condition (very damaging and the most costly of all putative false positive outcomes).

These numbers matter. They’re essential to the claim that the risks of breast cancer screening outweigh the benefits.

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Information Overload

By |December 21st, 2009

Americans are consuming unprecedented amounts of information. Some small fraction of that – what we read, hear and see on TV – relates to health and illness. Today’s sources might include a story on cell phones and cancer, an NPR feature on autism or a commercial in which Sally Fields recommends Boniva, a drug for osteoporosis.

Does knowing more help us lead better, healthier lives?

In Bits, a NY Times blog on business, innovation, technology and society, Nick Bilton recently described our voracious appetite for enlightenment: 34 Gigabytes or, depending on how you count, nearly 12 hours’ worth of data-gleaning per day from diverse channels like television, radio, the Web, text messages and video games.

The Bits piece links to the Global Information Industry Center‘s “How Much Information?” (HMI?) project that issued a December 2009 paper. The research center, based at the University of California in San Diego, dates to 1960, when the Internet was, if anything, theoretical, and the concept of sharing computer-based data a matter of defense.

As best I can tell, the topics of “health” and “cancer” don’t figure prominently in the recent analysis. Maybe we don’t want to know much more on these subjects than we find in our doctors’ offices. But long runs of TV shows like “Marcus Welby, M.D.,” “ER” and “Scrubs” suggest otherwise. Indeed, many tune in regularly for a peek into the medical world, at least when fed in bits and pieces by idealized or heart-throb fictitious physicians with complex, warm and sometimes hot personal lives.

Nearly two-thirds of U.S. adults seek health-related information on the Web, says Susannah Fox of the Pew Research Center’s Internet & American Life Project. The agency tracks how North Americans use the Internet for medical purposes and published an update, “The Social Life of Health Information” earlier this year.

Dr. Kevin Pho touched on the issue in a December 16 post on KevinMD:

To be sure, doctors and other health professionals don’t get everything right. But anyone can find information on the web, which can be of dubious accuracy.

Knowing what to do with that data can only come with experience and training.

Fox, of the Pew Research Center, commented:

…one of our key findings is that most people use on-line health resources to supplement advice they get from doctors and other health professionals. After 10 years of researching this field, we have no evidence that the internet is replacing traditional sources of medical advice. Yes, many people are gathering and sharing health information online, but they are also discussing it with friends, family, and health professionals.

I was considering the matter last week, it happens, when I received an email from a former patient. He has hemochromatosis, an inherited disposition to iron overload. His body is programmed to take in excessive amounts of iron, which then might deposit in the liver, glands, heart and skin. He offered holiday greetings and mentioned “some amazing videos on hematology and hemochromatosis and genetics” he’d discovered on YouTube.

This is the future of medicine, I realized. A patient accesses public databases, videos and other resources to learn about signs and symptoms of his illness, what foods to eat or best avoid, what medicines and treatments he might need and if his condition is likely to affect others in his family.

Whether physicians want their patients to search the Internet for medical advice is beside the point. We’re there already, whether or not it’s good for us and whether what we find there is true.

The current issue is not about limiting non-professionals’ access to facts or fiction. Rather, it’s about how we might sift through so much material – whether that’s a CNN segment we take in, passively, while running on a treadmill in the gym, or a detailed analysis of a new prostate cancer treatment provided straight from an oncologist – and digest it properly.

Perhaps information is a bit like iron, an essential nutrient that makes us stronger. To benefit from such a surplus, we’ve got to somehow identify, process and absorb what’s useful, what helps and doesn’t hurt.

Patients using internet health information without physician guidance

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Legitimate Concerns and Unfortunate Timing on Radiation from C.T. Scanning

By |December 15th, 2009

This week’s cancer news features a study in the current issue of the Archives of Internal Medicine, first reported by Reuters:

CHICAGO (Reuters) – Radiation from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 Americans, researchers said on Monday:

…The findings, published in the Archives of Internal Medicine, add to mounting evidence that Americans are overexposed to radiation from diagnostic tests, especially from a specialized kind of X-ray called a computed tomography, or CT, scan.

The risks of radiation from CT scanning will almost certainly add to the current confusion and concerns about the risks of breast cancer screening.

Mammography differs from CT scanning in several important ways:

1. Mammograms involve much less radiation exposure than CT scans.

According to the American Cancer Society, a typical mammogram uses between 0.1 to 0.2 mSV per image. So even if multiple images are taken of each breast, the total dose remains under 1 mSV.

Another source, the Health Physics Society, estimates a dose of 0.7 mSV per mammogram. So if a woman were to have a screening mammogram every other year between the ages of 40 and 49, she’d receive approximately 3.5 mSV in total from those procedures.

By contrast, a single CT scan involves over a 10-fold greater amount of radiation (such as 8 mSV for a CT of the chest, 10 mSV for a CT of the abdomen) according to the Health Physics Society fact sheet.

2. Mammography is well-regulated by the Food and Drug Administration (FDA) and other agencies.

The Mammography Quality Standards Act (MQSA) requires mammography facilities across the nation to meet uniform quality standards. The law, first passed in October, 1992, requires all mammography facilities to 1) be accredited by an FDA-approved accreditation body, 2) be certified by FDA, or its State, as meeting the standards, 3) undergo an annual MQSA inspection, and 4) prominently display the certificate issued by the agency.

3. Women who undergo screening mammograms can control when and where they get this procedure.

Screening mammograms are elective by nature; a woman can choose an accredited screening facility and, in advance, learn something about its reputation and screening methods. Most women between the ages of 40 and 50 are capable of tracking their mammograms, whether they choose to have those annually, biennially, or less often.

Many CT scans are ordered for patients who are in the hospital – a very different sort of circumstance. Many hospitalized patients don’t feel well, don’t understand what’s happening to them and/or lack the needed assertiveness or language skills to ask about a scan before it’s done.

Summary:

Mammography is a relatively safe and highly-regulated procedure in the U.S.  The recent news on risks from radiation in CT scanning should not confound the discussion of breast cancer screening.

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How Well Do You Really Want to Know the “Red Devil?”

By |December 11th, 2009

I know what it’s like to get the “red devil” in the veins.

You can learn about Adriamycin, a name brand chemotherapy, on WebMD. Or, if you prefer, you can check on doxorubicin, the generic term, using MedlinePlus, a comprehensive and relatively reliable public venture put forth by the National Library of Medicine and National Institutes of Health. If you’re into organic chemistry, you might want to review the structure of 14-hydroxydaunomycin, an antibiotic and cancer therapy first described 40 years ago in the journal Biotechnology and Bioengineering.

from the National Center for Biotechnology Information (NCBI) database, http://pubchem.ncbi.nlm.nih.gov, accessed 12/11/09.

from the National Center for Biotechnology Information (NCBI) database, http://pubchem.ncbi.nlm.nih.gov, accessed 12/11/09.

When I was a medical student, I studied some facts about doxorubicin hydrochloride, enough at least to answer a few questions during pharmacology exams. Later, as a resident in internal medicine, I knew the drug to be an anthracycline, a chemotherapy that intercalates into DNA, wreaking havoc in cells’ genetic material and reducing the replication potential.

As an oncology fellow, I prescribed and administered the clear, intense red fluid to patients with lymphoma and breast cancer. I learned to be careful: if the medicine slips from the intravenous catheter and enters the nearby, tender tissue below the skin, it can harm. The drug commonly causes hair loss and stomatitis; mouth sores can be so painful it hurts to eat, even when the nausea doesn’t squelch your hunger, or talk. Adriamycin affects the bone marrow, where blood cells are produced, and heart.

It’s not an easy drug; my patients knew this and so did I.

This month marks seven years since my first dose of Adriamycin, part of the “A/C” regimen that’s sometimes given to breast cancer patients. Was it worth going bald, getting anemia, sluggishness, mouth sores, chemo brain and all else that I experienced? Yes; I have no doubts. But I was lucky; my tumor was small and I needed only a few cycles.

I never knew Adriamycin as the red devil until a few years ago when a friend’s stepmother, undergoing treatment, used the term in an email.  She’s a woman who read lots of blogs and shared her experiences with other breast cancer patients on-line. I realized that despite working in an academic medical center and regularly communicating with physician-friends and oncologists at meetings, I still had a few things to learn.

Now that I’m writing about cancer, I wonder what sorts of information people really want or need to make informed decisions. I suppose some would like to know the chemical structure of doxorubicin before receiving such a potentially poisonous, possibly life-saving drug. Maybe a patient’s husband, or daughter, would seek details about the half-life, metabolism in the liver, side effects and more.

When I received my chemotherapy, I didn’t want to read about breast cancer or treatments. Rather, I chose an oncologist I trusted and liked. Then, for the most part, I followed her advice. But this sort of strategy’s not for everyone, particularly for patients who don’t know their doctors as I knew mine. Besides, most cancer patients aren’t already board-certified oncologists.

With so much available data at our fingertips, some patients will amass many resources about their condition. Others will be more passive, mainly listening to their physicians or perhaps, to friends and family members who do the research on their behalf. To a large extent, it’s a matter of personality –

Ultimately, you can’t know everything about Adriamycin until you’ve had it in your veins. Whether being familiar with the chemical structure makes a difference, is less certain.

What’s clear is this: with so much information at our disposal, there’s an opportunity for patients to help doctors make better decisions.

(all links accessed 12/11/09)

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Doctors Don’t Tweet

By |December 7th, 2009

I didn’t know much about social media until the summer of 2008. Then, I entered Columbia University’s Graduate School of Journalism as a new student and attended an optional lunch-time session on Facebook, Gmail and Twitter.

My kids used Facebook, so I knew about that. Still, I hesitated to sign on to something so un-private, so revealing, so exposed. I asked the dean of students if joining Facebook was essential to my participation in the graduate program.

“Not exactly,” he said. “But if you want to be a journalist, you probably should.”

So I did. Over the course of 10 tough academically dense months, I saw streams of status updates, invitations to parties, news flashes and pix. Finding Facebook friends is easy, I learned, if you’re spending your days amongst people half my age.

Still, I wasn’t entirely comfortable. Physicians are professionals, reserved and careful.

Gradually a few of the moms I know from my kids’ school connected. Some of them are using Facebook for professional purposes, others maybe to assuage boredom. Some, I suspect, joined to monitor their teenagers’ lives. (I didn’t.) More recently, a bunch of my high school classmates reunited on-line. A few friends from college met up there, too.

But my physician friends – some 25 years’ worth since I entered med school – aren’t in sight.

The New England Journal of Medicine first approached this somewhat sensitive subject last summer in an article “Practicing Medicine in the Age of Facebook.”

I wonder when the Journal will talk on Twitter.

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A Note about Medical Lessons

By |December 4th, 2009

Dear Readers,

The idea of this blog is to consider how people – patients and doctors both – find and interpret medical information, communicate and make informed decisions.

There’s a lot to cover –

Some upcoming topics: health on-line, white coats, dealing with disability, opting for palliative care and more.

Thanks everyone, for your support and interest!

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On Juno and Screening Test Stats

By |December 3rd, 2009

——–
“Well, well” says the convenience store clerk. “Back for another test?”

“I think the first one was defective. The plus sign looks more like a division symbol, so I remain unconvinced,” states Juno the pregnant teenager.

“Third test today, mama-bear,” notes the clerk.

Juno recluses herself and uses a do-it-yourself pregnancy test in the restroom, on film.

“What’s the prognosis … minus or plus?” asks the clerk.

…”There it is. The little pink plus sign is so unholy,” Juno responds.

She’s pregnant, clearly, and she knows she is.

(from Juno the movie*)
——-

Juno\’s pregnancy test
——-
Think of how a statistician might consider Juno’s predicament – when a testing device is useful but sometimes gives an unclear or wrong signal.

Scientists use two terms – sensitivity and specificity – among others, to assess the accuracy of diagnostic tests. In general, these terms work best for tests that provide binary sorts of outcomes – “yes” or “no” type situations. Sensitivity refers to how well a screening tool detects a condition that’s really present (pregnancy, in the teenager’s case). Specificity, by contrast, measures how well a test reports results that are truly negative.**

Juno’s readout is relatively straightforward – a pink plus sign or, not; the possibilities regarding her true condition are few.

Still, even the simplest of diagnostic tests can go wrong. Errors can arise from mistakes in the procedure (a cluttered, dirty store is hardly an ideal lab environment), from flawed reagents (the package might be old, with paper that doesn’t turn vividly pink in case of pregnancy) or from misreading results (perhaps Juno needs glasses).

Why does this matter, now?

The medical and political news are dense with statistics on mammograms; getting a handle on the costs of cancer screening requires more information than most of us have at our disposal.

Of course, breast cancer is not like pregnancy. Among other distinguishing features, it’s not a binary condition; you can’t be a little bit pregnant.  (Both are complicated, I know.)

To get to the bottom of the screening issue, we’ll have to delve deeper, still.

——-
*Thanks Juno, Dwight and everyone else involved in the 2007 film; details listed on IMBD.

———

**I was surprised to find few accessible on-line resources on stats. For those who’d like to understand more on the matter of sensitivity and specificity, I recommend starting with a 2003 article by Tze-Wey Loong in the British Medical Journal. This journal, with a stated mission to “help doctors to make better decisions” provides open, free access to anyone who registers on-line.

I’ll offer an example here, too:

To measure the accuracy of Juno’s kit, a statistician might visit a community of 100 possibly pregnant women who used the same type of device. If 20 of the women are indeed pregnant (as confirmed by another test, like a sonogram), but only 16 of those see the pink plus sign, the sensitivity of the test would be 16/20, or 80 percent. And if, among the 80 women who aren’t due, 76 get negative results, the specificity would be 76/80, or 95 percent.

False negatives: among the 20 pregnant women 4 find negative results; the false negative rate (FN) is 4/20, or 20 percent.

False positives: among the 80 women who aren’t pregnant 4 see misleading traces of pink; the false positive (FP) rate is 4/80, or 5 percent.

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