Prognosis after ipsilateral breast tumor recurrence and locoregional recurrences in five national surgical adjuvant breast and bowel project node-positive adjuvant breast cancer trials

Purpose Locoregional failure after breast-conserving surgery is associated with increased risk of distant disease and death. The magnitude of this risk in patients receiving chemotherapy has not been adequately characterized. Patients and Methods Our study population included 2,669 women randomly assigned onto five National Surgical Adjuvant Breast and Bowel Project node-positive protocols (B-15, B-16, B-18, B-22, and B-25), who were treated with lumpectomy, whole-breast irradiation, and adjuvant systemic therapy. Cumulative incidences of ipsilateral breast tumor recurrence (IBTR) and other locoregional recurrence (oLRR) were calculated. Kaplan-Meier curves were used to estimate distant-disease-free survival (DDFS) and overall survival (OS) after IBTR or oLRR. Cox models were used to model survival using clinical and pathologic factors jointly with IBTR or oLRR as time-varying predictors. Results Four hundred twenty-four patients (15.9%) experienced locoregional failure; 259 (9.7%) experienced IBTR, and 165 (6.2%) experienced oLRR. The 10-year cumulative incidence of IBTR and oLRR was 8.7% and 6.0%, respectively. Most locoregional failures occurred within 5 years (62.2% for IBTR and 80.6% for oLRR). Age, tumor size, and estrogen receptor status were significantly associated with IBTR. Nodal status and estrogen and progesterone receptor status were significantly associated with oLRR. The 5-year DDFS rates after IBTR and oLRR were 51.4% and 18.8%, respectively. The 5-year OS rates after IBTR and oLRR were 59.9% and 24.1%, respectively. Hazard ratios for mortality associated with IBTR and oLRR were 2.58 (95% CI, 2.11 to 3.15) and 5.85 (95% CI, 4.80 to 7.13), respectively. Conclusion Node-positive breast cancer patients who developed IBTR or oLRR had significantly poorer prognoses than patients who did not experience these events.