More than a third of breast cancer survivors gradually stop getting annual mammographies, according to a new study.

The results may indicate women grow complacent about medical screening once they get past the medical scare, said the study's lead author, Dr. Chyke Doubeni of the University of Massachusetts.

Others said it's more likely survivors avoid screenings because they dread a recurrence of the cancer and additional treatment.

"They're fearful something's going to be found," said Dr. Kathryn Edmiston, a Worcester, Mass., oncologist who specializes in breast cancer patients.

The study found just 63 percent of women were getting annual mammographies five years after breast cancer surgery. The findings are reported in Cancer, a medical journal published by the Atlanta-based American Cancer Society.

About 2.3 million U.S. women have been treated for breast cancer, and they are considered to be at three times the risk for tumors in the other, unaffected breast than women with no such medical history.

The American Cancer Society recommends all women 40 and older get an annual mammography, the procedure for taking an X-ray of the breast. But studies have shown only about 58 percent of women over 40 actually do.

Few studies have looked at how often breast cancer survivors get mammographies.

"The assumption has been that once women have had breast cancer, they're going to recognize the value of a mammography and get it done," Edmiston said.

In this study, researchers reviewed medical records for 797 women who were diagnosed with breast cancer in 1996 or 1997. All were 55 and older, though the average age was about 69 1/2. All received care from health systems in Detroit, Minneapolis, Oakland, Calif., or Worcester, Mass. More than 80 percent were white.

About 40 percent had one breast removed, and 55 percent had a lumpectomy or some other form of breast-conserving surgery. Women who'd had double mastectomies were not included.

About 80 percent of the women had mammographies within the first year after surgery, but the percentage dropped to 63 by the fifth year, the study found.

Older women, particularly those with other ailments, were less likely to get the tests as the years went by. Women who saw a doctor annually were more likely to get them.

Also, women who underwent breast-conserving treatment were more likely to get mammographies than women who'd had a mastectomy.

It's possible that both complacency and fear may be keeping some women from follow-up mammographies, said Robert Smith, the American Cancer Society's director of cancer screening.

Also, doctors may be failing to remind women to get the exams. "The recommendation and endorsement of physicians can overcome those issues" — fear and complacency, Smith said.