Don’t Blur the Message on Cancer Screening

I hope this week’s headlines and editorials don’t add to the blurriness of the public’s perception of cancer screening – that people might begin to think it’s a bad thing all around. The details matter….screening 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.

New Studies on Colon Cancer Screening by Colonoscopy and Fecal Blood Testing

My take is that periodic colonoscopy has the potential to halve the number of deaths from colon cancer in the general population…As to how colonoscopy relates to fecal blood testing as a screening method at the population level, and the optimal start and frequency of either test, those remain uncertain.

Stepping Back, and Thinking Forward to October

A question central to today’s discussion – which does at least acknowledge the decline in breast cancer mortality – is the extent to which mammography is responsible for this trend, as opposed to other factors such as increased awareness about cancer, better cancer treatments and other variables.

Another Erroneous Report on Breast Cancer Screening by Mammography

What the authors tried to do was analyze trends in breast cancer mortality in relation to mammography’s availability in distinct regions of Denmark over several decades. Using Poisson regression, a form of statistical analysis, they looked for a correlation and found none. They concluded that they couldn’t detect a benefit of screening mammograms among Danish women who might benefit (see below).

Here’s what I think are the two most serious flaws in this observational study:

Peter Sings Colonoscopy

Am I pro- or con- colonoscopy for routine screening, you might wonder. Well, that depends.

Am I pro- or con- famous singers and other celebrities extolling the benefits of particular medical interventions? Well, that depends, too.

But I’m sure I prefer “Puff the Magic Dragon.” Also “Leaving on a Jet Plane” fills me with imperfect memories of 6th grade.

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

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.

I’ll answer as might a physician and board-certified oncologist who happens to be a BC survivor in her 40s: we need establish how often false positives lead, in current practice, to additional procedures and inappropriate treatment…These numbers matter. They’re essential to the claim that the risks of breast cancer screening outweigh the benefits.

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

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.
2. Mammography is well-regulated by the Food and Drug Administration (FDA) and other agencies. The Mammography Quality Standards Act (MQSA) requires…
3. Women who undergo screening mammograms can control when and where they get this procedure. Screening mammograms are elective by nature..

On Juno and Screening Test Stats

“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.

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

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

(see clip from Juno the movie*)

Think of how a statistician might consider Juno’s predicament…

Getting the Math on Mammograms

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?

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…

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