Most experts believe that regular breast cancer screening for women 40 and older means more breast cancer is diagnosed earlier, when it's more treatable. This means lives are saved. Still, doctors continue to discuss and study the effect screening for breast cancer has on public health, as well as the best time to start screening.
In the study reviewed here, researchers question the value of regular screening mammograms because routine mammography seems to have had little effect on reducing the number of women who die from aggressive forms of breast cancer. The researchers also question the value of routine prostate cancer screening (the PSA test) in men.
The researchers analyzed the results of seven earlier studies that evaluated the effect routine screening mammograms had on the diagnosis and outcomes of breast cancer. After accounting for changes in breast cancer treatments (hormonal therapy, for example), the researchers found that regular mammograms:
Based on these results, it might seem reasonable to conclude that current breast cancer screening recommendations make sense. But the researchers also said:
The researchers think that regular screening mammograms detect more early-stage breast cancers that won't become aggressive, advanced-stage disease. But regular screening mammograms aren't translating into better detection of aggressive, advanced-stage breast cancers. The researchers also suggest that some of the very early-stage breast cancers detected by screening mammograms may never grow, and so are over-treated because they've shown up on a mammogram.
Many women have had breast cancer diagnosed early and undergone successful treatment because of screening mammograms. So it might be hard to understand how experts could question the value of regular screening. It helps to look at the issue from both a large, public health viewpoint and a smaller, individual health viewpoint.
Looking at breast cancer screening from a public health perspective means looking at the effect that screening has on the entire population, including weighing the outcomes brought about by the screening against the cost. Public health experts also look at whether the money spent on screening could be used in other ways that might offer more benefits. From a public health perspective, the hope is that increasing early-stage breast cancer diagnoses through regular mammograms would decrease diagnoses of aggressive, advanced-stage breast cancer. This study suggests this hasn't happened. So it's reasonable to ask if routine screening as currently recommended makes sense.
From an individual health perspective, if you or someone you know had early-stage breast cancer diagnosed and treated because a screening mammogram detected an area of concern, it's likely that you consider regular mammograms extremely valuable. Questioning the value of screening mammograms may seem senseless to you.
Based on all of the evidence available today, Breastcancer.org continues to believe that current standards recommending routine screening mammograms for women age 40 and older with an average risk of breast cancer make sense. We also believe that the debate sparked by this research is healthy and makes doctors and health policy experts look critically at what's being done to improve the health of all people -- and ask whether it could be done more effectively.
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 told the New York Times, that the benefits of screening have been exaggerated.
In the JAMA paper, Esserman wrote that the screening push seemed like a logical way to reduce cancer mortality. For both breast and prostate cancer "there are remarkable differences between outcomes of localized versus advanced disease (breast cancer: five-year relative survival rates of 98.1% versus 27.1%; prostate cancer: 100% versus 31.7%)."
And the penetration of the screening has been significant (MedPage Today) -- 70% of women 40 or older say they have had a recent mammogram and 50% of at-risk men have routine PSA testing.
But 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."
Esserman suggested that the problem may be that early detection "may not be the solution for aggressive cancers because many may not be detected early enough for a cure."
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."
The article "grew out of collaboration initiated within the Early Detection Research Network and was supported by grants U01CA111234 and U01CA086402."
Esserman and colleagues reported no financial disclosures.
Primary source: Journal of the American Medical Association Source reference: Esserman L et al "Rethinking Screening for Breast Cancer and Prostate Cancer" JAMA 2009; 302: 1685-1692.
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