Ob-Gyn Group Recommends Annual Mammograms in 40s

July 20, 2011 -- Women in their 40s should have a mammogram every year just like older women, the nation's largest group of ob-gyns now says.

The American College of Obstetricians and Gynecologists (ACOG) had previously recommended mammograms every one to two years beginning at age 40, with annual screening recommended after age 50.

The policy change is being made to simplify the breast screening message to women in their 40s, and in recognition of the fact that breast cancers tend to grow more quickly in younger women, says breast cancer specialist Mary Gemignani, MD, of New York's Memorial Sloan-Kettering Cancer Center.

"We know that the earlier a breast cancer is detected, the greater the chance for cure," Gemignani tells WebMD. "While it is true that only a small percentage of women in their 40s develop breast cancer, it is also true that we may be risking the opportunity for early detection if we don't screen these women annually or do not screen at all."

Comparing Guidelines of Different Organizations

ACOG now joins the American Cancer Society, the American College of Radiology, and several other health groups in recommending annual mammogram screenings for women in their 40s.

A major exception is the government's health policy group, the U.S. Preventive Services Task Force (USPSTF), which now says women can wait until age 50, if they choose, to begin mammogram screening. The decision to start regular mammogram screening before age 50 should be an individual one, according to the USPSTF. The group also recommends screening every two years instead of annually.

A woman's lifetime risk of developing breast cancer is about 12%, but fewer than 2% of women in their 40s develop the disease.

American Cancer Society Director of Cancer Screening Robert Smith, PhD, says even though only about one woman in 69 will develop breast cancer in her 40s, delaying screening until age 50 and screening every two years means that some women will die needlessly.

"The problem is that we can't tell an individual woman in her 40s with any degree of certainty that she won't be the one woman in 69," Smith tells WebMD. "The good news is that mammography works pretty well. It is true that there is inconvenience and discomfort and overtreatment, but there is no doubt that screening has contributed to a significant reduction in breast cancer deaths."

Age Factor in Breast Cancer Detection

The time interval from when a breast cancer is detectable with mammography to when the cancer grows big enough to cause symptoms is referred to as the sojourn time.

Age is the biggest predictor of sojourn time, with women in their 40s having the shortest average interval of two to 2.4 years, compared to around four years for women in their early 70s.