Posts Tagged ‘5-year cancer survival rate misleading’

What MDs don’t know about cancer screening

The majority of primary care physicians support cancer screening. In fact, a key component of their practice is sending symptom-free individuals in for routine exams. However, whether you’re a patient just following instructions or a clinician ordering tests, having a thorough understanding of cancer screening statistics is essential for making well-informed decisions. The majority of primary care physicians in the United States, according to a recent survey, believe that screening is effective despite false numbers.

The online poll, which was created by a German and American research team with experience in attempting to improve public and professional comprehension of health statistics, was completed by 412 doctors. Researchers from the Max Planck Institute for Human Development in Berlin, Germany, under the direction of Odette Wegwarth, PhD, discovered that “most clinicians wrongly attributed greater survival and early discovery as proof of lives saved.” “Few correctly grasped that the only evidence of the value of screening is reduced mortality in a randomized trial.” The poll’s findings were released this week in Annals of Internal Medicine.

The survey gave doctors two ways to explain a hypothetical screening test’s effects: in one, it improved 5-year survival and enhanced early detection, while in the other, it cut cancer mortality and increased incidence. The hypothetical test situations were based on actual data from the European prostate-cancer screening randomized trial, despite the fact that the type of cancer was not specified. Additionally, the percentage of stage I prostate cancers and 5-year survival rates were derived from the 1975 U.S. cancer statistics database. That year was picked out of caution because it was before the implementation of any formalized prostate cancer screening program.

The authors of the survey found that doctors were more impressed by “irrelevant evidence,” such as a test with a high 5-year survival rate. Here’s why it doesn’t matter: Our bodies develop more malignancies as we age, many of which may never be life-threatening. For instance, the vast majority of times, prostate cancer is a slow-moving or non-progressive malignancy.

Because most men will die of other causes, the 5-year survival rate for prostate cancer will appear to be a strong argument in favor of early cancer detection. Six years after being diagnosed, somebody could pass away and still be considered a “survivor”. Furthermore, screening frequently advances the time between diagnosis and treatment without advancing the period between death and diagnosis. (By the way, we can thank the American Cancer Society for using this incredibly deceptive method of calculating the value of a cancer screening test for such a long time. In the not-so-distant past, the American Cancer Society actually used the terms “cure” and “5-year survival” interchangeably, leading generations of cancer patients to believe that reaching that milestone signified something.)

Now for the second concerning finding: The physicians who participated in the poll were less pleased by a test that was said to have “reduced mortality.” And a test that detects a lot of cancer made them more impressed. But compared to persons who seek medical assistance only when symptoms arise, screening for cancer will almost always result in more cancer cases being discovered. This is because screening inaccurately inflates the apparent value of a screening test by finding many more tumors that do not advance (a phenomenon that the survey authors describe as overdiagnosis). For this reason, cautious researchers will assess the total death rates of both the screened and unscreened groups after many years of follow-up. It is the only way to distinguish between individuals who had unnecessary treatment for a cancer they didn’t need to be aware of and those who genuinely benefited in a way that saved their lives.

Researchers can also calculate the “cost” of screening in terms of damages using this comparison. What the European prostate cancer screening trial discovered was as follows: For each death from prostate cancer that is prevented in the PSA screened Guys, 48 men, experienced serious side effects as a result of needless therapy for a non-progressive cancer.

What to do

Before undergoing any cancer screening test, educate yourself at the National Cancer Institute’s website.  And be sure to use the “health professional” version which, compared to the patient version, is more open and thorough. Plan on frequent visits to this website for fact-checking the media if you primarily obtain your medical information from ( See its recent excellent critique criticizing the media’s interpretation of the most recent data on colon cancer screening, notably The New York Times’ inaccurate portrayal of it as unquestionable evidence that colonoscopy is the best screening approach. Click here

Maryann Napoli, Center for Medical Consumers©