Screening Mammography Still Saves Lives!

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With recent articles fueling the debate about the effectiveness of screening mammography, it is important for physicians and patients to understand that there is abundant sound scientific evidence demonstrating that screening mammography saves lives.  The American Cancer Society’s recommendation for annual screening mammography starting at age 40, supported by UCSF Radiology, is based on randomized, controlled trials and large observational studies.  For about 50 years prior to 1990, death rates from breast cancer were unchanged.  With the advent of screening mammography in the U.S. (around 1985), the breast cancer diagnosis death rate has declined more than 30% since 1990.

Recent guidelines issued by the United Preventive Services Task Force (USPSTF) suggested women screen beginning at age 50 and only every other year. Using the same models employed by the Task Force, Hendrick and Helvie* calculated that following USPSTF guidelines of screening every other year beginning at age 50 would sacrifice almost 100,000 lives to breast cancer among women currently aged 30-39.  Hence, UCSF Radiology continues to support annual screening mammography starting at age 40.

Anxiety related to false positives is a real phenomenon.  However, at UCSF, we choose to find ways to minimize anxiety through prompt diagnostic work up and prompt communication with our patients. According to Hubbard et al, breast cancer screening every other year results in fewer false positives.  That is expected.  Taken to the extreme, not screening at all will result in no false positives. Attitudinal surveys have shown that the majority of American women are tolerant of many false positive mammography exams if associated with a benefit of early breast cancer detection and breast cancer mortality reduction.

In most cases, a woman who is “recalled” from screening mammography will return for a few additional mammographic images and/or a breast ultrasound and will be reassured that everything is fine as soon as the exam is completed.  Only 1-2% of screened women are recommended to have a biopsy (usually a needle biopsy under local anesthesia as an outpatient).  However, of these women who undergo biopsy, about 20-30% will be found to have breast cancer.  In comparison, there are actually more false positives (lower cancer yield) when breast lumps discovered on physical exam are biopsied.

Like all screening tests, mammography has false positives, but it also has been proven to reduce mortality from breast cancer.  Women need to understand that if they choose to screen less frequently or forgo mammography altogether, they are also forgoing some or all of the potentially life-saving benefit.

For more information on Women’s Imaging at UCSF, please see here.

*Hendrick RE, Helvie MA. United States preventive services task force screening mammography recommendations: science ignored. AJR Am J Roentgenol. 2011Feb;196(2):W112-6. PubMed PMID: 21257850.