The American Cancer Society has revised its guidelines on mammograms, suggesting that women be screened later and, at some point, not as often.

There is some flexibility in the report, which is published in the Journal of the American Medical Association, that women have options about when to begin screening, and how often to be screened. It said women who are 40-44 should have the option to begin screening before age 45, and women age 55 and older should be able to continue with annual screenings.

“I think we’ve given average-risk women a roadmap that is tailored to their risks and personal preference,” said Dr. Robert A. Smith, vice president of cancer screenings for the American Cancer Society. “Our message is that you can start at 40. It’s your decision if you want that additional insurance. Regular mammograms are like insurance. Most women will not develop breast cancer in their lifetimes, but regular mammograms are a good preventive measure.”

Previously, the recommended age to begin screenings was 40. He said about 6 percent of breast cancers are diagnosed from ages 40-44; 10 pehttp://www.cancer.org/rcent, ages 45-49; and 12 percent, ages 50-54.

He said they have not heard much criticism, but some people were unhappy.

“I think it’s crazy,” said Melissa Miller, a nurse and mother of two who was diagnosed with stage 3 breast cancer at age 38. “It makes no sense.”