Wednesday, October 21, 2009

Analysis questions prostate and breast cancer screening methods

Courtesy of the New York Times

Two decades after the explosion in cancer screening fueled by reimbursement for mammography and prostate specific antigen (PSA) testing, a new analysis suggests that it is time to rethink the push for early detection of these two cancers. There is no argument that more cancers are being detected and at a much earlier stage, but that increase has not resulted in a decrease in metastatic disease, according to Laura Esserman, MD, MBA, of the University of California, San Francisco, and colleagues, who made their case in a special communication published in the October 21 issue of the Journal of the American Medical Association.

In broad strokes they painted a picture of increased detection and costly treatment of cancers that pose minimal risk, without making a dent in killer cancers. The researchers touched a nerve with the commentary and the American Cancer Society has already gone on record saying that it is reconsidering its position on the risks and benefits of breast and prostate cancer screening. Otis Brawley, MD, chief medical officer of the society, said that the benefits of screening have been exaggerated.

When prostate cancer mortality in the U.S. was compared with the rate in United Kingdom -- where PSA screening is not recommended -- there was no difference, although the incidence of prostate cancer was dramatically higher in the U.S. For breast cancer, seven randomized trials found a relative reduction in mortality ranging from 20% to 30%, but the "observed decrease in mortality is attributable to both screening and adjuvant therapy, with an estimated decrease of 7% to 23%, and 12% to 21%, respectively."

What is an effective screening technique is the detection of premalignant lesions, which is exactly what occurs with both colonoscopy and pap smears, two screening strategies that have significantly decreased invasive colorectal and cervical cancers.

Esserman argued that it is time to develop new screening strategies -- possibly new biomarkers -- that will be able to differentiate between "significant- and minimal-risk cancers." At the same time, she recommended new strategies to "reduce treatment for minimal-risk disease" and calls for the development of "clinical and patient tools to support informed decisions about prevention, screening, biopsy, and treatment and offer treatments tailored to tumor biology."

Bonnie - I anticipate that there are many health professionals and patients out there who are a bit peeved with this report.

10/22/09 Note: The American Cancer Society says it is not currently rethinking its stance on cancer screening, as was widely reported. "We are not redoing or rethinking our guidelines at this time, nor are we going to restate our guidelines to emphasize the inadequacies of screening," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society.

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