There's no evidence that women 75 and older should discontinue regular mammography screening, according to a study presented at RSNA 2016 in Chicago. In fact, researchers from the University of California, San Francisco (UCSF) found that women between the ages of 75 and 90 continue to benefit from screening.
"The continuing increase of cancer detection rate and positive predictive values in women between the ages of 75 and 90 does not provide evidence for age-based mammography cessation," said study lead Dr. Cindy Lee in a statement released by the RSNA.
Exactly when women should start and stop regular mammography screening has been under heated debate. Current guidelines from the U.S. Preventive Services Task Force (USPSTF) state that there isn't enough evidence of benefit to recommend screening in women 75 and older. However, the research used to set this guidance hasn't included older women, according to Lee.
"All prior randomized, controlled trials excluded women older than 75, limiting available data to small observational studies," she said.
Lee's group used data from the National Mammography Database, evaluating more than 5.6 million screening mammograms performed between January 2008 and December 2014. The exams were done at 150 facilities across 31 U.S. states. Lee and colleagues analyzed patient demographics, screening mammography results, and biopsy results; they also sorted the exams into five-year patient age increments.
The researchers calculated screening mammography performance using the following metrics: cancer detection rate, recall rate, positive predictive value for biopsy (PPV2), and biopsy performed (PPV3). They found a mean cancer detection rate of 3.74 per 1,000 patients, a recall rate of 10%, a PPV2 rate of 20%, and a PPV3 rate of 29%. In addition, all of these performance metrics gradually improved as women aged.
The findings support the argument that deciding when to stop breast cancer screening should involve each woman's personal health history and preferences, according to Lee.
"We know that the risk of breast cancer increases with age," she said. "With the uncertainty and controversy about what age to stop breast cancer screening, we want to address this gap in knowledge using a large national database."