There is no clear cut-off age at which breast cancer screening should be stopped, a study conducted in the US has found.

The findings of what is said to be “the largest-ever study on screening mammography outcomes“ were presented at the annual meeting of the Radiological Society of North America, which is being held this week.

A mammogram is an X-ray picture of the breast. Doctors use a mammogram to look for early signs of breast cancer, and needs to be followed up by additional tests, such as biopsy, to detect cancer.

Contentious issue

The press release on the study said that the age at which to stop mammography screenings has been a controversial and confusing issue. So far, there was not enough clarity on whether or not women older than 70 or so should get mammographies done, as the pain of this followed by other gruelling check-ups may outweigh the benefits.

In 2009, the United States Preventive Services Task Force released guidelines that said that there was not enough evidence to access the benefits and harms of screening mammography in women who are 75 years of age and older.

For the recently presented study, researchers from the University of California, San Francisco, used the National Mammography Database and looked at more than 5.6 million mammograms in 150 facilities across the US, performed over seven years till December 2014. The research team also looked at patient demographics, screening mammography results and the biopsy results.

“This research adds support for guidelines that encourage screening decisions based on individual patients and their health status,” the press release issued by the Radiological Society said.

“All prior randomised, controlled trials excluded women older than 75, limiting available data to small observational studies,” said Dr Cindy S Lee, from the University of California in the press release.

The study led by Dr Lee found continuing increase in the cancer detection rate and positive predictive value (for those women for who a biopsy was recommended or performed) in women between the ages of 75 and 90.

The other collaborators of the study, apart from Dr Lee include Dr Debapriya Sengupta, Mythreyi Bhargaven-Chatfield, Dr Edward Sickles, Dr Elizabeth Burnside, Judy Burleson, and Dr Margarita Zuley.