Women whose breast cancer is detected by screening mammography are more likely to be treated with breast conservation and without chemotherapy compared with women whose cancer is detected during a physical exam, a study shows.

“If you are unlucky enough to develop breast cancer, it would be best if you could be treated with effective therapy that is minimally toxic,” Dr. Richard J. Barth, Jr. from Dartmouth Medical School and the Norris Cotton Cancer Center, Lebanon, New Hampshire told AMN Health.

“Annual mammography increases the chances that women in all age groups who develop breast cancer will be able to be treated with minimally toxic therapy,” he said.

Among 992 women with invasive breast cancer, 532 had their cancer detected by physical examination and 460 by screening mammography.

Tumors detected by screening mammography were half the size and less than half as likely to be node-positive, meaning the cancer has spread to the lymph nodes, as tumors detected by physical examination, the authors report in the American Journal of Radiology.

Only 7 percent of the tumors detected by physical examination were smaller than those for which chemotherapy is recommended, compared with one third of those detected by screening mammography.

Only 28 percent of women whose breast cancer was detected by screening mammography received chemotherapy, the report indicates, compared with 56 percent of women whose breast cancer was detected by physical examination.

Women whose cancer was detected by screening mammography were almost twice as likely to be treated with breast-conserving therapy, which involves limited surgery and radiation, versus mastectomy as women whose cancer was detected by physical examination, according to the study.

The study also shows that women whose tumors were detected by physical examination were nearly 3 times as likely to be treated with chemotherapy and 2.5 times as likely to be treated with mastectomy rather than breast conservation, compared with women whose tumors were detected by screening mammography.

“Screening mammography for the detection of invasive breast cancer allows tumors to be diagnosed at an earlier stage, thereby allowing patients who have developed breast cancer to be treated adequately with less-toxic therapy,” the authors conclude.

“I think it is very important that internists and family physicians hear about these research findings, because they are the ones who are ordering [treatments and] counseling patients about this,” Barth told Reuters Health.

SOURCE: American Journal of Radiology, January 2005.