Breast Cancer Screening

Breast cancer screening should definitely not be stopped at a specific age, as there is no sufficient evidence to suggest screening should be stopped. The study was co-authored by Dr. Cindy Lee, assistant professor in residence at the University of California-San Francisco, and team. They presented their findings at the Radiological Society of North America (RSNA) annual meeting, held in Chicago, IL.

Breast cancer is the most common form of cancer among American women, following skin cancer. The American Cancer Society reports that 246,660 new cases of invasive breast cancer will be diagnosed in the U.S. this year, and more than 40,000 women will die from the disease. Even though these are grim statistics, breast cancer death rates have been falling in the U.S. since the late 1980’s. This is a trend that has been attributed party to earlier detection as a result of the screening.

The gold standard of breast cancer screening is mammography. The technique uses x-rays to identify early signs of breast cancer as calcifications or tumors in breast tissue. The U.S. Preventive Services Task Force (USPSTF) guidelines issued in 2009 recommended that women aged 40-49 and at average risk of breast cancer, should make an individual, informed decision as to whether they undergo mammography, but those aged 50-74 should undergo mammography every 2 years. For those women aged 75 and older there is insufficient evidence to assess the balance of benefits and harms of screening mammography according to the USPSTF. However, the American Cancer Society recommends that women aged 56 and older should undergo mammography every 2 years and screening should continue as long as a woman is in good health and expected to live 10 more years or longer.

There is a lot of controversy, debate and conversation regarding the different breast cancer screening guidelines among the major national organizations. Randomized and controlled trials assessing mammography outcomes have excluded women aged 75 and older and the data has been based on results of small, observational studies. More than 5.6 million screening programs that took place at 150 facilities across 31 U.S. states between January 2008 and December 2014 were assessed by researchers.

The researchers applied four standard performance measures: cancer detection rate, recall rate (% of mammograms that require follow-up testing), positive predictive value for biopsy recommended and biopsy performed. The team used data from more than 2.5 million women aged 40 and older, then they were divided into age groups by 5-year intervals up to the age of 90.

Positive predictive value represented the number of cancers identified through mammography that resulted in biopsy or recommended biopsy. Higher cancer detection rate, higher PPV2 and PPV3, and lower recall rate reflected an optimal mammography performance.

The team identified an overall mean cancer detection rate of 3.74, a 10% recall rate, a 20% PPV2 rate and a 29% PPV3 rate for every 1,000 patients. They also identified an increase in cancer detection rate and a gradual rise in PPV2 and PPV3 rates and fall in recall rates with increasing age. The evidence for age-based mammography cessation was not provided for ages 75 and 90.

It was concluded that their findings suggest it should be a woman’s individual choice as to whether she wants to cease or continue with the screening at age 75 and older. The benefits of screening after the age of 74 may outweigh the risks, but further investigation is needed.

–Dr Fredda Branyon