Switching sides in one of the most contentious issues in medicine, the AMA voted for the change Thursday, the final day of its annual five-day policy making meeting.
The decision puts the AMA at odds with the government and the American College of Obstetricians and Gynecologists, which say an interval of one to two years is adequate. But the AMA now agrees with the American Cancer Society and the American College of Surgeons.
The issue has pitted those who argue that routine mammograms are not cost-effective in younger women against those who say that the tests are needed and that the insurance industry should be paying for them.
Dr. Debra R. Judelson of Beverly Hills, Calif., a representative of the American Medical Women's Association, which supports annual screening, said managed-care companies have refused to pay for mammograms at less than two-year intervals for women under 50.
"The science does show us that cancers in this age group grow more rapidly," she said. "We do want to identify the disease early. But I cannot get all of my patients getting a yearly mammogram if they wish it, because the companies will only cover every two years."
She said insurers always translate "every one or two years" as meaning they only have to pay for mammograms every two years in younger women.
The AMA had previously advocated the one-to-two-year timetable for women in their 40s.
"One in six breast cancer deaths in 1995 were attributable to women diagnosed with breast cancer during their 40s," Richard B. Reiling, a spokesman for the American College of Surgeons, argued before the AMA's 494 policymaking delegates voted in favor of the change.
On the other side of the issue was Dr. Scott R. Karlan of the American Society of General Surgeons, who noted a 10-year study of 25,000 Canadian women found no benefit to mammography for women in their 40s.
"Even the studies that have been in favor of mammography have pointed out that the incidence of breast cancer is so low, and the sensitivity of mammography is so low in women between the ages of 40 and 50, that you would have to screen more than 250,000 women to find, perhaps, one curable case of breast cancer," Karlan said.
Thursday's vote does not affect AMA guidelines for women over 50 (which call for annual mammograms) nor the recommendation that a manual breast exam by a doctor be part of any physical exam in either age group.
The AMA's Council on Scientific Affairs said the cost-effectiveness of screening younger women is in line with that of other diagnostic procedures.
But others argued that annual screening will drive up insurance and HMO costs without proven benefit.
"There is no one in this room who would object o women having proper care. The issue involves the interpretation of data," said Dr. David M. Rosenthal of San Jose, Calif., a delegate who opposed the change.
Written By Brenda C. Coleman