The method by which benign lumps are discovered may determine whether women will continue to do breast self-exams, according to a study by University of Michigan researchers.

The study of 655 women found that those who discover a benign breast lump themselves are three times more likely to stop doing self-exams than are women who have never found a lump.

By comparison, women whose benign breast lumps are first detected by health professionals "are twice as likely to begin doing monthly breast exams or to do them more often than women who have never had a lump," said Nancy K. Janz, assistant research scientist at the University of Michigan School of Public Health and a co-author of the study.

The findings suggest, she said, that when women discover lumps themselves they are more likely to stop doing self-exams because of the anxiety, cost and discomfort involved in undergoing a biopsy to find out if a lump is benign or cancerous.

Monthly breast self-exams, one of the best ways to detect cancer in its early stages, are recommended by the American Cancer Society and other health groups.

"Women who find the benign lump themselves sometimes feel that they triggered the unpleasantness by their own actions, so almost unconsciously some may decide not to chance such an experience again," Janz said.

Those who performed breast self-exams occasionally, but had failed to find a lump, were also more likely to stop doing the exams after a biopsy was performed. "They lost confidence in their ability to do it," Janz said.

By contrast, women whose lumps were discovered by someone else "don't feel responsible for what followed," she said, and were more likely to start doing exams on a regular basis.

Janz and her co-author Marshall H. Becker, professor of health behavior and education at the University of Michigan, recommend that physicians reinforce the need for self-examination at the time biopsy results are discussed. The study found that only about half of women were encouraged to continue the self-exams. "The percentages should be higher," she said.