The American Cancer Society has revised its guidelines for when and how often women should receive screenings for breast cancer.

The group suggests women start yearly breast scans at age 45 instead of 40 and for healthy women to have scans every other year at ages 55-74.

Historically there has been much disagreement over the right time and frequency for mammograms.

New suggestions are more aligned with those of a US government panel.

Announced on Tuesday, the advice is aimed toward women at “average” risk for breast cancer, and doctors suggest more screening for women at higher risk.

Higher risk factors include certain genetic mutations and family history of cancer.

“The most important message of all is that a mammogram is the most effective thing that a woman can do to reduce her chance of dying from breast cancer,” said Dr Richard Wender of the American Cancer Society.

Breast cancer is uncommon for women under 40 and starting mammograms too early may result in “false alarms”, he said.

The group also advises doctors to stop doing routine physical breast exams, due to a lack of evidence of them being effective at saving lives.

The Susan G Komen foundation, a major US breast cancer research and advocacy organisation, disagrees with the guidelines and has said in a statement that women and their doctors should decide on the right time for screening based on individual risk.

“Ultimately, women must have better and more accurate information about their individual risk for breast cancer so that they and their providers can make informed decisions about the screening schedule that is right for them. Knowledge is power,” said Dr Judy Salerno, president of the organisation.

About 40,000 women in the US die from breast cancer each year, with 200,000 being diagnosed per year.

The guidelines were published in the Journal of the American Medical Association.