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…
|
|||||
|
A seemingly slight adjustment in a statistic, for teaching purposes, can significantly change a test’s calculated value.… See more A Closer Look at the Details on Mammography, in Between the Lines The new findings have no bearing on whether or not cancer screening is cost-effective or life-saving. What the study does suggest is that med school math requirements should be upped and rigorous, counter to the trend See more What Does it Mean if Primary Care Doctors Get the Answers Wrong About Screening Stats? 
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. See more New Studies on Colon Cancer Screening by Colonoscopy and Fecal Blood Testing 
The latest issue of the Annals of Internal Medicine contains 2 noteworthy papers on cervical cancer screening. The first, a systematic review of studies commissioned by the USPSTF, looked at 3 methods for evaluating abnormalities in women over 30 years: high-grade cervical cell dysplasia (Dr. E. Uthman, Wikimedia Commons) 1. Conventional cytology (as in a Pap smear; the cervix is scraped and cells splayed onto a microscope slide for examination); 2. Liquid-based cytology (for LBC, the NHS explains: the sample is taken as for a Pap test, but the tip of the collection spatula is inserted into fluid rather than applied to slides. The fluid is sent to the path lab for analysis); 3. Testing for high-risk HPV (human papillomavirus). Currently 3 tests have been approved by the FDA in women with atypical cervical cells or for cervical cancer risk assessment in women over the age of 30: Digene See more Cervical Cancer Screening Update: on Pap Smears, Liquid-based Cytology and HPV Days ago, the USPSTF issued a new draft for its recommendations on routine PSA measurements in asymptomatic men. The panel’s report is published in the Annals of Internal Medicine. The main findings are two: first, the absence of evidence that routine PSA testing prolongs men’s lives, and second, that PSA evaluation may, on balance, cause more harm than good. Not surprisingly, there’s been considerable coverage of this by the media, and some controversy. For decades, many men have had their PSA checked, knowingly or not, by their physicians. The PSA test measures the level of Prostate Specific Antigen, a protein produced and sometimes secreted by prostate cells, normal, inflamed or malignant, into the bloodstream. As an oncologist, I don’t find the panel’s recommendations surprising. There’s never been strong data to support the hypothesis that routine PSA testing reduces mortality for men in any age group. Prostate cancer is often indolent, See more 3 Differences between Prostate and Breast Cancer Screening Today’s cancer news is about screening for prostate cancer. The U.S. Preventive Services Task Force will advise that men should not be screened by a PSA (prostate specific antigen) blood test. The new recommendations will apply to asymptomatic men in all age groups. I happen to agree with the task force’s position on this, but the point I’d like to make is obvious but too-often missed by the press and others who consider cancer screening: Prostate cancer is not the same as breast cancer. Rather, each is a distinct set of related diseases with varied prognoses and treatment options. For any screening method, the potential benefit of detecting cancer early depends on the specific tumor type, the accuracy of the test, and the likelihood that treatment will be effective and confer a net benefit over risks. A key to understanding the screening debate(s) is not to conflate data for distinct 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. Among my hundred questions about this enterprise — notwithstanding the ethics of performing clinical trials in hospice patients, as is related in the Times article – is this: does the dye harm the kidneys? As for how much it costs, that’s not said either. Because Alzheimer’s is a fairly common disease and memory loss an even commoner condition, the potential demand for this marketable diagnostic method might be great. What are we thinking? See more The New Alzheimer’s Plaque Test (and early breast cancer detection) 
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: See more Another Erroneous Report on Breast Cancer Screening by Mammography 
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. See more Peter Sings Colonoscopy After a while my oncologist stepped out into the waiting area and guided me to the hall by her office. “The cells are low,” she said. “We’ll have to wait another week, that’s all.” I knew she was right. But a week seemed like a lifetime to me then.… See more A Visit With My Oncologist 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. 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.. See more Legitimate Concerns and Unfortunate Timing on Radiation from C.T. Scanning “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… See more On Juno and Screening Test Stats 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. …Women are ignoring the numbers, choosing reassurance over hard facts. Some say members of the pro-mammogram camp are irrational, even addicted… See more Stats in the News! 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. We need to set the bar higher for mammography… See more Another Take on Mammography 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? See more Getting the Math on Mammograms 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… See more To Screen is Human |
|
||||
|
Copyright © 2013 Medical Lessons - All Rights Reserved Powered by WordPress & Atahualpa newsletter software |
|||||
connections…