Are mammography guidelines making breast cancer deadlier?

(CBS) The debate over mammography is heating up again.

A government panel sparked a controversy in late 2009 by issuing guidelines calling for routine mammography breast cancer screenings to start at age 50 for most women rather than age 40, as many doctors had long recommended. But new research seems to suggest that those guidelines are reducing women's odds of having breast cancer detected early, when treatment is more likely to be effective.

In one recent study, University of Colorado scientists saw a significant drop in mammograms in women in their 40s, according to a written statement issued in conjunction with the studies. In another, scientists at Case Medical Center in Clevand showed that breast tumors detected in women who underwent mammography in their forties tended to be at a much earlier stage than breast tumors detected in women who did not have screening mammograms.

"Seventy percent of women who are diagnosed with breast cancer don't have a family history of breast cancer," Dr. Donna Plecha, director of breast imaging at Case Medical Center, said in the statement. "It's very important that we continue to do all that we can to catch breast cancer in the earliest stages so that we can continue to save lives."

What does the American Cancer Society say? Its chief medical and scientific officer, Dr. Otis Brawley, told HealthDay that routine annual screening mammograms should begin at age 40.

Not so fast, said Dr. Virginia A. Moyer, the Baylor College of Medicine doctor who chairs the U.S. Preventive Services Task Force that issued the guidelines.

"The benefit in 40- to 49-year-old women is pretty small," Dr. Moyer said about annual mammography, according to CNN."There is a real but rather modest benefit. There are also risks."

Risks include false positives, indicating cancer when there is none. That can lead to anxiety and to needless biopsies.

About one in eight women will develop invasive breast cancer at some point. In 2007 - the most recent year for which numbers are available - 202,964 women in the U.S. were diagnosed with breast cancer, and 40,598 died of the disease, according to the Centers for Disease Control and Prevention.

The American Cancer Society has more on mammography and early detection of breast cancer. 

What do you think? Are the federal guidelines for mammography exposing women to needless risk?