"The basic assumption that screening programs that find and treat early stage disease will then prevent late-stage disease, or prevent cancer from spreading, may not always be correct," added Thompson. "If a tumor is aggressive, finding it early may not prevent death."

Thompson is professor and chairman of the Department of Urology and holds the Glenda and Gary Woods Distinguished Chair in Genitourinary Oncology at the Cancer Therapy & Research Center at the UT Health Science Center at San Antonio and the Henry B. and the Edna Smith Dielmann Memorial Chair in Urologic Science at the UT Health Science Center. He led the Prostate Cancer Prevention Trial, a study of 18,882 men from around the U.S. that demonstrated that the drug finasteride reduces a man's risk of prostate cancer by 24.8 percent.

In contrast to breast and prostate cancer, screening for cervical and colon cancer -- and the removal of abnormal tissue - has led to a significant drop in invasive cancer. Screening is "most successful when pre-malignant lesions can be detected and eliminated" such as during colonoscopies, said the authors.

The authors suggest that to improve screening, "a new focus is recommended for research and care to identify markers that discriminate minimal-risk from high-risk disease (and) identify less aggressive interventions for minimal-risk disease to reduce treatment burden for patients and society."

The authors list four recommendations in their call to action for early detection and prevention:

Develop tests to distinguish between cancers that are lethal and those that are low-risk. Reduce treatment for low-risk disease. Diagnosing cancers that don't kill the patient has led to treatment that may do more harm than good. Develop tools for physicians and patients to help them make informed decisions about prevention, screening, biopsy and treatment. Offer treatments individually tailored to a patient's tumor. Work to identify the people at highest risk for cancer and use proven preventive interventions.

"Over the years we have worked hard to find new treatments and new ways of finding disease and many of these interventions when appropriately assessed have saved lives," said Otis W. Brawley, MD, chief medical officer of the American Cancer Society, and professor of hematology, oncology and epidemiology at Emory University.

"It is very appropriate that we occasionally step back, assess and reflect on what we in medicine are doing," he added. "In the case of some screening for some cancers, modern medicine has overpromised. Some of our successes are not as significant as first thought. Cancer is a complicated disease and too often we have tried to simplify it and simplify messages about it, to the point that we do harm to those we want to help."

Yiwey Shieh, a medical student at the UCSF Medical School and former research assistant with Esserman, is also a co-author of the article.

Source: University of California - San Francisco