MINNEAPOLIS — Susan G. Komen for the Cure, the largest breast-cancer advocacy group, was criticized by doctors for overstating the benefits of mammograms and failing to tell women about the risks in its last public advertising campaign.

The most recent Komen ads urged regular mammograms and implied that skipping them was harmful, Steven Woloshin and Lisa Schwartz, directors of the Center for Medicine and the Media at Dartmouth Medical School in Hanover, N.H., wrote Sunday in the British Medical Journal.

The advantages are much less clear, and women should be told the positive and negative to make an informed decision, they said.

Cancer-screening programs have been questioned in recent years as studies showed they can identify tumors that may never cause harm, though treating them has physical, emotional and financial implications.

The U.S. Preventive Service Task Force spurred controversy starting in 2009 with its recommendations to limit mammograms at younger ages for women and eliminate a standard prostate-cancer test for men.

"We think Komen can do a lot better by giving women the information they need to weigh the benefits and the harms," Woloshin said. "They aren't doing a good job. The ads are misleading and give false promises."

The ads emphasize that five-year survival for breast cancer is 98 percent when caught early and 23 percent when it's not.

Those percentages are apples and oranges, Woloshin said, and can't be directly compared. A tiny tumor, detectable only with advanced screening, may take more than five years to kill a woman, while one that can be felt by hand would be deadly faster, regardless of whether any treatment is used.

If the tumor is relatively harmless and destined to never cause any symptoms for the woman, identifying it early would lead to emotional turmoil, physical pain and side effects from fighting it and wasted expense, he said.

Breast cancer killed an estimated 40,000 women last year and is the second-leading cause of death among women, exceeded only by lung cancer, according to the Atlanta-based American Cancer Society. For every woman whose life is saved because of screening, two to 10 other women are diagnosed unnecessarily and treated with drugs that give them no benefit, Woloshin said.

The Komen group, battered by a controversy over its since-revoked decision to end about $680,000 in grants to Planned Parenthood, declined to comment directly on the criticisms about its ad programs. Instead, it emphasized the benefits of screening and its efforts to further cancer research.

"Everyone agrees that mammography isn't perfect, but it's the best widely available detection tool that we have today," said Chandini Portteus, Komen's vice president of research, evaluation and scientific programs. "The numbers are not in question. Early detection allows for early treatment, which gives women the best chance of surviving."