Stats in the News!

False positives have hit the headlines.

Check the New York Times, Wall Street Journal, CNN – they’re everywhere. Even the Ladies’ Home Journal skirts the subject.

The discussion on mammography runs something like this: studies show that cancer screening save few lives. Among women younger than 50 years, there’s a high rate of false positive results. Those misleading tests lead to more imaging procedures such as sonograms and MRIs, additional biopsies and, necessarily, higher screening costs.

Women are ignoring the numbers, choosing reassurance over hard facts. Some say members of the pro-mammogram camp are irrational, even addicted.

The best response is to look carefully at the research findings.

Two recent publications sparked the current controversy: one, a single paper in the Journal of the American Medical Association and the other, a cluster of articles in the most recent Annals of Internal Medicine. Using a variety of research tools, the authors in both journals examine the effectiveness of cancer screening. Here, the investigators consider the risks and benefits of mammography from a medical perspective; they don’t focus on monetary aspects of the issue.

The problem of false positives in mammography is most-fully addressed in the AnnalsScreening for Breast Cancer: An Update for the U.S. Preventive Services Task Force. The authors assess, among other newsworthy subjects (such as the value of breast self-examination) the potential risks and benefits of mammography. In the Results section, they delineate five sorts of mammography-associated harms (see “key question 2a”):

1. Radiation exposure – not a big deal, the exposure level’s low;

2. Pain during procedures – women don’t mind this, at least not too much;

3. Anxiety, distress and other psychological responses – the patronizing terms tell all;

4. False-positive and false-negative mammography results, additional imaging, and biopsies – the subject of this and tomorrow’s posts;

5. Over-diagnosis – this interesting and, in my view, exaggerated issue warrants further discussion.

For now, let’s approach the problem of false positives in mammography (as in #4, above).

What is a false positive?

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

How often do these occur?

To their credit, the Annals authors state clearly: “published data on false-positive and false-negative mammography results, additional imaging, and biopsies that reflect current practices in the United States are limited…”

Before we can establish or even estimate the costs of false positives in screening mammography, medical or economic, we need to better define those and, then, establish the frequency with which they occur.

Turns out, the calculation’s not so simple as you might think.

Related Posts:

A Note on False Positives

A colleague sent me an email about my math. You’re more or less right, he said, but you need to account for the false positives.

I agree with him. (It’s true.)

The problem is, among others, how to present those numbers in the press.

Statistics don’t sell; still, an explanation is due.

In my next full post I’ll consider the meaning of false positives  – their significance and costs –  in the cancer screening debate.

Related Posts:

Dinner with my Family

I come from a family of doctors. My dad is a retired physician. He’s a son of immigrants who attended med school on a scholarship. For decades he practiced internal medicine together with his younger brother, my closest uncle.  They cared for countless adults, gradually absorbing their patients’ spouses and siblings, children and grandchildren into their burgeoning practice.

Our dinners at home were punctuated by calls from the answering service about all sorts of emergencies. Every night at the end of the meal, my father would sit at the table sipping tea, returning patients’ calls to discuss their test results and concerns. Sitting in the next room, doing my homework, I heard about tumors, pain, headaches, heartburn and heart attacks. I learned about symptoms, blood tests and the concept of a differential diagnosis. You name it, pretty much any illness, and I might have answered a few questions. It was a bit like watching “House,” but on-stage, in my home.

Family gatherings centered on two things – food, and talk about medicine. We spoke of interesting cases (always nameless), challenging conditions and, even back then, the constraints of health care costs. My fiancé, now husband of over 20 years, couldn’t get over how debate over health care dominated our Rosh Hashanah and Thanksgiving feasts.

Now I’m getting to my point –

I grew up learning about medicine, and I understood the terms early on.  I’d been a patient, too, in and out of orthopedists’ offices and disfiguring braces in my adolescence, and then in the hospital with inexplicable fevers, blood clots and more.  All that, before becoming a physician, doing research and taking care of people facing the most serious of illnesses.

As a patient, I entered the doctor’s office armed with information. Seven years ago, when I learned I had breast cancer, I knew exactly what to do. The decisions, though difficult, were almost straightforward, buttressed by my knowledge and familiarity with the language of medicine.

Tomorrow, over dinner, I don’t want to talk about mammograms.  Or health care reform, or even the swine flu. But I do want to learn and exchange ideas.

People – patients and doctors both  – need to speak a common language. Just as at the dinner table, the conversation moves forward only if we keep our minds open, listen carefully and communicate with mutual respect.

Stay tuned!

Related Posts:

Another Take on Mammography

In my latest piece, Mammography: a Not-So-Fatalistic View, I outline reasons why the recent task force findings on mammography don’t hold.

Three key issues have escaped the headlines:

1. The expert panel carried out a careful analysis using data that are, necessarily, old;

2. The recommendations don’t apply to digital mammography;

3. Mammograms are not all the same – the quality varies by the methods used and skills of the radiologists who read them.

We need to set the bar higher for mammography. If everyone could have a state-of-the-art mammogram, as I did some years ago, followed by a sonogram to better analyze the tiny abnormalities the radiologist noted (before rushing to biopsy), the stats on cancer screening would be incontrovertible; there would be no debate.

Related Posts:

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.

Related Posts:

Hello Readers!

Well, I went ahead and started this blog without a proper introduction. Why was I in such a hurry?

Because I think the media’s getting – and giving – the wrong message on breast cancer screening. When it comes to long, boring medical publications like those published this week in the Annals of Internal Medicine, perhaps it’s not the devil that’s in the details so much as are the facts.

More on that tomorrow –

I read somewhere that for a blog to be successful you have to let people know a bit about the author and her life.  Besides, if I obsess only about cancer and its treatments it’d be hard for readers to come back for more.

So I’ll start with this:  I live in Manhattan and am really glad to be alive.

Thanks everyone, for reading and sharing!

Related Posts:

To Screen is Human

Smack in the midst of October-is-breast-cancer-awareness-month, the Journal of the American Medical Association published a provocative article with a low-key title:  “Rethinking Screening for Breast Cancer and Prostate Cancer.”  The authors examined trends in screening, diagnosis and deaths from cancer over two decades, applied theoretical models to the data and found a seemingly disappointing result.

It turns out that standard cancer screening is imperfect.

The subject matters, especially to me.  I’m a medical oncologist and a breast cancer survivor, spared seven years ago from a small, infiltrating ductal carcinoma by one radiologist, an expert physician who noted an abnormality on my first screening mammogram.

The New York Times featured the new findings in a front-page article that elicited over 200 readers’ comments.  Quite a few cheered the frank, non-party line that mammography‘s not all it’s cracked up to be.  Same goes for measuring the prostate specific antigen in men’s blood, a test that sometimes marks for prostate cancer.

Some readers connected the dots between cancer screening, the pharmaceutical industry and physicians’ income.  Because doctors make money by interpreting scans, doing biopsies and giving chemotherapy, perhaps they can’t be trusted to make unbiased recommendations.  Like an aggressive tumor, the story spread everywhere – cable news, NPR, a host of blogs.

Fear, hassle, insurance forms (if you’re lucky), blood tests, anxiety, CAT scans, possibly a cancer diagnosis with attendant surgery, radiation, chemotherapy, nausea and who knows what else ensues.  Yuck.  The toll is huge, even apart from the finances.

The Food and Drug Administration estimates that radiologists perform some 37 million mammograms each year in the United States.  Women undergo 70 percent of those scans for routine screening purposes.  (Doctors order the other 30 percent to evaluate lumps or other signs of cancer that’s already evident.)  My math:  that’s 26 million screening mammograms at, roughly, $100 per scan, for a total cost of $2.6 billion annually.

Compounding the confusion, a few days later the Times ran a related piece highlighting reports that some tumors shrink or even disappear without treatment.  That’s wonderful news, if it’s true.  Perhaps you can skip the mammogram, not find the cancer, and it’ll just go away.

This represents a form of wishful thinking.  Reality check in three points:

1. Prostate cancer is not the same as breast cancer.  You can’t simply lump these together in a study and draw conclusions about testing or treatment for either condition.

2.  Breast cancer is a common and very real cause of death in North America, where each year there are nearly 200,000 new cases and more than 40,000 associated deaths.

3. Mammograms save lives by uncovering tumors when they’re still small enough for surgical removal.

In 2009, there is no known cure for metastatic breast cancer.  A woman’s chances of surviving for five years after she’s found to have a small, localized tumor lie in the 98 percent range; if she’s noted with metastatic disease, those odds hover around 25 percent.

So what’s a woman to do?

Sure, it’s discomfiting to know that screening doesn’t always work.  And for some, it’s disheartening that doctors, insurance companies and x-ray machine makers generate profits by detecting, evaluating and treating cancer.  In case you haven’t been following the health care reform debate, health care’s an imperfect business.

Many will continue to go for annual mammograms, especially in October, and their doctors will, emphatically, recommend that they get those.  And many men will request of their internists, or urologists, or whoever’s taking care of them, that they get a blood test for prostate cancer, “just to be sure.”  Likely, a few more skeptics will opt out of the screening process.

Screening for breast and prostate cancer could be better.  The same applies to pretty much everything in health care, as in any human enterprise.  But it’s the best that we’ve got, for the time being.

Related Posts:

newsletter software