Postmastectomy radiation therapy (PMRT) for some breast cancer patients can reduce their risk of recurrence by almost 30 percent and increase their five-year overall survival by almost 50 percent, according to a study in the June 1 issue of the International Journal of Radiation Oncology*Biology*Physics, the official journal of the American Society for Radiation Oncology (ASTRO).
Surgery and radiation are common methods for treating early-stage breast cancer and preventing recurrences. While several studies have been done on the routine use of PMRT in breast cancer patients with larger tumors and four or more positive lymph nodes, the role of PMRT for smaller tumors with one to three positive lymph nodes (T1-2 N1) is not known.
Researchers retroactively studied 544 patients with T1-2 N1 invasive breast cancer who were treated with modified radical mastectomy between April 1991 and December 2005. Of the patients, 383 did not receive radiation therapy and 161 did. Radiation therapy reduced the risk of recurrence in patients who were younger than 40 years old, T2 stage, high nuclear grade, had negative estrogen receptor status and had presence of lymphovascular invasion from 40 percent to 12.5 percent and increased the overall survival of T1 N1 breast cancer patients with negative estrogen receptor status and presence of lymphovascular invasion from 43.7 percent to 87.1 percent.
"Even though the study sample size was small, we feel that the results are compelling," Po Sheng Yang, M.D., a physician in the Sun Yat-Sen Cancer Center Department of Surgery in Taipei, Taiwan, and lead author of the study, said. "Based on this study, we strongly suggest that radiation therapy be used after mastectomy for this particular group of breast cancer patients."