For many, particularly men, the shocking pink on the field at many NFL games is a vivid reminder that October is Breast Cancer Awareness Month. For women, however, the message about breast cancer is perhaps a bit less vivid.

Women who have kept up with the mammogram debate in the last few years may be ready to tear their hair out, and understandably so. Two of the major advising organizations — the American Cancer Society (ACS) and the U.S. Preventative Services Task Force (USPSTF) — have been at odds about how to advise women on when to begin routine breast cancer screening. The ACS says that women in their 40s should have them; the USPSTF says it’s better to wait until the 50s.

Now there's new information. A study that looked backward in time, comparing breast cancer diagnoses to women’s mammogram history, suggests that women do indeed benefit greatly from screening in their 40s. Not to screen during these years, the authors conclude, is simply too risky, since cancers in this age range can be the most dangerous.

A study that looked backward in time, comparing breast cancer diagnoses to women’s mammogram history, suggests that women do indeed benefit greatly from screening in their 40s.

The researchers followed all the women who were diagnosed with invasive breast cancer from 1990 through 1999 at Partners HealthCare Hospitals, and tracked them through 2007. Of the 609 women who developed breast cancer, 71% of the women had not had screening, while the other 29% had. Exactly half of the deaths from breast cancer occurred in women under 50 years old.

“The biological nature of breast cancer in young women is more aggressive, while breast cancer in older women tends to be[slower],” said study author Blake Cady in a statement. “This suggests that less frequent screening in older women, but more frequent screening in younger women, may be more biologically based, practical, and cost effective.”

The study also documented encouraging news about breast cancer treatment over the years. In 1969, about 50% of the women diagnosed with breast cancer died in the next 12.5 years. But of the group of women in the current research, fewer than 10% died by 2007. “This is a remarkable achievement, and the fact that 71 percent of the women who died were women who were not participating in screening clearly supports the importance of early detection,” said co-author Daniel Kopans.

Some researchers have argued that routine mammograms may lead to over-diagnosis and unnecessary treatments, since the screening may pick up masses that aren’t actually cancerous.

Kopans says the design of many of these studies is faulty, since they don’t directly compare a woman’s risk of death with her own medical history. “None of these papers has actually looked at individual women but have used registry data, and this has led to false conclusions…This present paper examines each woman as an individual with direct data on who was screened and which women died of breast cancer. It addresses the question from a different and unique perspective.”

The authors conclude that screening in a woman’s 40s is important and potentially life-saving. If you’re confused about when to begin, it’s still important to talk with your doctor who can give you advice based on the newest research and your own medical and family history. Whether this new study is enough to sway the USPSTF to align their recommendations more closely with those of the ACS is not clear — but it looks like the research is leading us in that direction.

The study is published in the journal Cancer.