Cessation of screening mammography should not be based on age but on patient preferences and health status, researchers suggest.
Dr. Cindy Lee of NYU Langone Medical Center in Garden City, New York, told Reuters Health that as a breast imager, she is often asked if patients aged 75 years and older should continue to be screened.
“There is not enough evidence out there to determine how breast cancer screening benefits women older than 75,” she told Reuters Health.
“In fact, all previous randomized trials of screening mammography excluded people older than 75 years,” she said by email. “Unfortunately, age is the biggest risk factor for breast cancer, so as patients get older, they have higher risks of developing breast cancer. It is therefore important to know how well screening mammography works in these patients.”
To investigate, Dr. Lee and colleagues analyzed clinical data on screening mammographies done between 2008 to 2014 on more than 2.5 million women (3.5% with a personal history of breast cancer) at 150 mammography facilities across the U.S. The data included patient demographics, clinical findings, screening mammography interpretation and biopsy results.
Patients were grouped by age in five-year intervals, starting at age 40.
“We relied on four measurements to evaluate how well screening works,” Dr. Lee explained. The first was recall rate - how many women were called back for additional imaging - which is directly proportional to the rate of false positives.
The second was the cancer detection rate - the number of cancers found per 1,000 screening exams. The third and fourth measures were the positive predictive values (PPVs) for biopsy recommended (PPV2) and for biopsy performed (PPV3)“A good screening exam should have a low recall rate and a high cancer detection rate and PPVs,” she noted.
As reported in JAMA Oncology, online April 20, overall, the mean recall rate was 9.6%, with a statistically significant decrease from 14.5% in women 40 to 44 to 6.1% in those 90 and older.
The mean cancer detection rate per 1,000 screens was 3.74 overall, with a statistically significant increase from 1.72 in women 40 to 44 to 6.58 in those 90 and older.
PPV2 and PPV3 also increased significantly with age. PPV2 rose from 8% in women 40 to 44, to 38% in those 90 and older. Similarly, PPV3 rose from 11% in those 40 to 44 to 69% in those 90 and older. According to the authors, these trends persisted in a longitudinal trend analysis.
“We were surprised by how well screening works in older people,” Dr. Lee said. “Knowing before we started that this is a disease that affects older patients, we expected to see more screening-detected cancers in older women.”
“But,” she continued, “what was surprising was the recall rate and the number of false positives both decreased in older women.”
“The difference is statistically significant and shows us that screening should not stop cold at age 75. Our results suggest that we should continue screening for as long as the patient can live for another seven to 10 years and the patient would desire treatment if cancer was found,” she concluded.
Dr. Ermelinda Bonaccio, Clinical Chief of Breast Imaging, Roswell Park Cancer Institute in Buffalo, New York, told Reuters Health the study “supports previous recommendations that there is no specific cutoff age when women should stop having routine mammograms.”
“The authors’ recommendation is that the decision to continue annual mammography should be based on ‘individual patient values, comorbidities, and health status.’ This is in alignment with American Cancer Society Guidelines published in 2015, which recommend that women should continue routine mammography as long as their health is good and they have a life expectancy of greater than 10 years,” she concluded.