(USA TODAY) -- Many women view the monthly ritual of examining their breasts for lumps as a way of literally taking their health into their own hands.

They describe breast self-exams as empowering, as one of the few things they can do to protect themselves against the ravages of a dreaded and unpredictable disease.

After all, the American Cancer Society for years recommended that all women 20 and older perform monthly breast exams.

But no more.

In new screening guidelines released last week, the cancer society now calls self-exams optional. On its Web site, the group acknowledges "the shift is sure to be controversial, as there are various groups and individuals who believe breast self-exams are important to women's health."

One of the main reasons for the change is a lack of evidence that self-exams reduce women's risk of dying from breast cancer, says Debbie Saslow, director of breast and gynecologic cancer for the cancer society. By the time a lump can be felt, Saslow says, it probably has been there a long time, so it's more likely to have spread.

A study last year of more than 250,000 Shanghai women failed to show that self-exams saved lives. True, Chinese women generally don't have the same physiology or risk factors as U.S. women, Saslow says.

"What that study showed was not that BSE (breast self-exam) doesn't do anything, but if it does something in terms of saving lives, it's got to be a pretty small contribution," she says.

Meanwhile, Saslow says, self-exams can lead to anxiety and unnecessary biopsies because the majority of lumps women detect are benign.

Despite the guidelines shift, the Susan G. Komen Breast Cancer Foundation will continue to recommend monthly breast self-exams from age 20 on, president Susan Braun says.

Braun says a how-to video on self-exams is one of the most popular features of the Komen Web site. In addition, the foundation distributes instructions in multiple languages.

"To us, the idea of BSE is not exclusively to lower mortality," Braun says. "But it's for women to be in touch with their body, to understand changes in their own body."

Barbara Brenner, executive director of the San Francisco-based Breast Cancer Action, says that if patients were polled about how their tumors were picked up, about a third would say a self-exam revealed it.

Another third would say they or their partner accidentally found the lump, Brenner says, and only a third would credit mammography.

Though her group has never wholeheartedly endorsed self-exams because of questions about whether they save lives, Brenner says, they do help women become familiar with how their breasts normally feel.

"People who are terrified shouldn't do it, but to discourage people from knowing their bodies is a huge disservice," she says.

Self-exams serve another purpose, too, says Akua Jitahadi, a co-founder of Black Women for Wellness in Los Angeles.

"There's an audience of women that we lose if we don't keep breast self-exams," Jitahadi says. "It is a way to get many women to the next level of seeing a physician because they felt something."

Says Jitahadi: "It opens the door."

Copyright 2003 USA TODAY, a division of Gannett Co. Inc.