Over the past few years, I've been invited to speak twice at Lancaster General Hospital (PA) about studies of the effects of screening for colorectal and prostate cancer. Recognizing the need to further explore the controversies surrounding the evidence for these tests, Dr. Larry Bonchek kindly asked me to write a scientific commentary about these topics for the Journal of Lancaster General Hospital, which he edits. The result was the article "Challenging the Conventional Wisdom on Colorectal and Prostate Cancer Screening," just published in the journal's Fall 2010 issue. You are more than welcome to read the full article online, but here are my bottom-line conclusions for clinicians and patients:
The decision to perform screening for colorectal or prostate cancer can be complex, and should take in account evidence-based recommendations, the implications of recent studies, and patient preferences. In order to give patients accurate information on the benefits and limitations of cancer screening tests, physicians should discard “conventional wisdom” that has not been supported by scientific evidence. To briefly review:
1) Collecting a fecal occult blood sample for screening during the digital rectal examination is not “better than nothing at all.”
2) FOBT and flexible sigmoidoscopy have comparable benefits and fewer harms than screening colonoscopy.
3) Benefits of PSA screening on mortality are likely small to none.
4) Overdiagnosis and overtreatment of PSA-detected prostate cancers cause substantial harms.