BACKGROUND AND PURPOSE: Postoperative radiation therapy (RT) has been the subject of discussion, especially in patients with one to three positive lymph nodes (< or = 3 pN+) in the axillary dissection. The authors investigated whether postoperative RT provides a survival benefit for pT1-2 pN+ breast cancer patients. PATIENTS AND METHODS: Patients included were selected from the SEER database (NCI--Surveillance, Epidemiology and End Results, release 2000; n = 24,410) and the UZ Brussel database (1984-2002; n = 1,011) according to the following criteria: women aged 25-95, no previous cancer, unilateral pT1-pT2 breast tumors, total mastectomy (ME) or breast-conserving surgery (BCS), postoperative RT, and an axillary dissection showing at least one pathologic lymph node. RESULTS: The overall survival (OS) of patients in the SEER and UZ Brussel databases who received postoperative RT was identical. However, patients in the SEER database who did not receive RT had a significantly worse outcome (p < 0.0001). After ME or BCS, all patients (SEER and UZ Brussel) who had > or = 4 pN+ and received RT had comparable outcomes after 15 years. The 15-year OS in the subgroup with ME and < or = 3 pN+ nodes was 57.0% and 46.6% (p = 0.0004) with RT (UZ Brussel) and without RT (SEER), respectively. For BCS and < or = 3 pN+, the same significant difference in OS at 15 years was seen: 63.8% after RT (UZ Brussel) and 60.4% without RT (SEER; p = 0.0029). CONCLUSION: RT provides a survival benefit in patients with < or = 3 or > or = 4 pN+; the indication for postoperative RT should therefore be adapted in future consensus meetings.
