More than half the women aged 40 to 49 diagnosed with breast cancer on screening mammography reported no family history of the disease, supporting the benefit of yearly screening mammography for women in their 40s, according to a study presented May 3 at the annual meeting of the American Roentgen Ray Society in Vancouver.

The study, conducted by Stamatia Destounis, MD, and colleagues at Elizabeth Wende Breast Care in Rochester, N.Y., was a retrospective review of all breast cancers diagnosed at the group practice between 2000 and 2010. “We decided to look at our patients diagnosed with breast cancer in the 40 to 49 age group in lieu of recent proposed changes with mammography screening guidelines and the scrutiny over screening mammography," said Destounis in a statement.

Of all the cancers in women 40 to 49 years old, 373 were diagnosed from the screening population. Out of these cancers, 228 (61 percent) were found in women with no family history of breast cancer.

After excluding 17 who had a prior personal history of cancer or abnormal cells, the study cohort became 211 women. Patients were an average age of 45 at presentation, and 63.9 percent had cases of invasive disease; 15.6 percent had positive lymph nodes.

Ninety-one patients opted for treatment with lumpectomy and 43 opted for mastectomy. Of those treated with lumpectomy, eight proceeded to mastectomy after initial lumpectomy revealed residual disease or close borders. One patient with metastatic disease did not have surgery. Follow-up imaging revealed all but five are doing well, according to Destounis, but those five have been diagnosed with new or recurrent cancer.

"We weren't surprised by the results of the study, but the data do confirm that women in their 40s benefit from screening mammography yearly," said Destounis.