[Photo/Xinhua]

Women who were not known to be at increased risk of breast cancer should start biennial mammography screening at age 50 and continue through age 74, according to a final recommendation issued by an influential US panel Tuesday.

For women in their 40s, breast cancer screening every two years can also be effective but the decision to start screening should be an individual one, taking into account a woman's health history, preferences, and how she values the potential benefits and harms, the U.S. Preventive Services Task Force said.

Women in their 40s who have a mother, sister, or daughter with breast cancer may benefit more than average-risk women by beginning screening before age 50, it said.

"Our findings support a range of choices available to women -- from beginning regular mammograms in their 40s, to waiting until age 50 to begin screening, when the likelihood of benefit is greater," said the Task Force's Vice Chair Kirsten Bibbins-Domingo. "Women deserve to understand what the science says about mammography screening, so that they can make the best decision for themselves, in partnership with their doctor."

For women age 75 and older, the Task Force said it's unable to make a recommendation as none of the studies of breast cancer screening included women in this age group.

The Task Force also concluded that evidence is insufficient to determine the balance of benefits and harms in two additional areas: screening women with dense breasts; and the effectiveness of 3D mammography for the detection of breast cancer.

The Task Force is an independent, volunteer panel of US experts who regularly review the scientific evidence and make recommendations about clinical preventive services such as screenings, counseling services, and preventive medications.

Questions about when and how often women should get breast cancer screening have been a hot debate for years, as multiple organizations have issued mixed recommendations regarding mammogram screening, resulting in confusion for women.

In October 2015, another influential organization, the American Cancer Society, issued a largely similar guideline, suggesting most women should start getting annual screening at age 45 instead of 40 and then convert to biennial screening at age 55.

"The Task Force, the American Cancer Society, and many others have all affirmed that mammography is an important tool to reduce the risk of dying from breast cancer, and that the benefits of mammography increase with age," said Albert Siu, chair of the Task Force. "We hope this growing convergence among distinct organizations gives women and their health care providers confidence in the science that supports mammography screening."