Post-mastectomy radiation therapy (PMRT) for some patients with breast cancer can reduce their risk of recurrence by almost 30% and increase their 5-year overall survival by almost 50%, according to a study published in the June 1 issue of the International Journal of Radiation Oncology*Biology*Physics.
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 patients with breast cancer with larger tumours and 4 or more positive lymph nodes, the role of PMRT for smaller tumours with 1 to 3 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 aged younger than 40 years, T2 stage, high nuclear grade, had negative oestrogen receptor status, and had presence of lymphovascular invasion from 40% to 12.5%.
Radiation therapy increased the overall survival of patients with T1-2 N1 breast cancer with negative oestrogen receptor status and presence of lymphovascular invasion from 43.7% to 87.1%.
"Even though the study sample size was small, we feel that the results are compelling," said lead author Po Sheng Yang, MD, Sun Yat-Sen Cancer Center Department of Surgery, Taipei, Taiwan. "Based on this study, we strongly suggest that radiation therapy be used after mastectomy for this particular group of breast cancer patients."