Breast cancer patients who are treated with radiation after mastectomy have a reduced risk of recurrence, according to a study published in the International Journal of Radiation Oncology Biology Physics (2010 June 1;77(2):516-522).

Background information provided in the paper indicated that while past studies have explored the use of postmastectomy radiation therapy for larger tumors, its role for smaller tumors with one to three positive lymph nodes (T1-2 N1) is not known.

The new study, led by Po Sheng Yang, MD, a physician in the Sun Yat-Sen Cancer Center Department of Surgery in Taipei, Taiwan, included 544 patients with T1-2 N1 invasive breast cancer who were treated with modified radical mastectomy between April 1991 and December 2005. Among the participants, 383 were not treated with radiation therapy and 161 were treated with radiation therapy.

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The results of the study revealed that radiation reduced the risk of recurrence from 40% to 12.5% in patients who were younger than 40 years and had cancers with the following attributes: T2 stage, high nuclear grade, negative estrogen receptor status, and presence of lymphovascular invasion. In addition, radiation therapy was shown to increase the overall survival of these patients from 43.7% to 87.1%.

“Even though the study sample size was small, we feel that the results are compelling,” said Dr. Yang. “Based on this study, we strongly suggest that radiation therapy be used after mastectomy for this particular group of breast cancer patients.”