Abstract S3-2: Chemotherapy prolongs survival for isolated local or regional recurrence of breast cancer: The CALOR trial (Chemotherapy as Adjuvant for Locally Recurrent breast cancer; IBCSG 27-02, NSABP B-37, BIG 1-02)

Introduction Patients with isolated local and regional recurrences (ILRR) of breast cancer (BC) have a high risk of developing distant metastasis and dying from BC. We investigated the impact of chemotherapy (C) on disease-free survival (DFS) and overall survival (OS) after ILRR. Methods Patients with resected ILRR were stratified according to prior chemotherapy (yes vs. no), ER and/or PgR status of the recurrent tumor (both negative vs. either positive), and location of recurrence (breast vs. scar/chest wall vs. lymph nodes). Radiation, hormone and HER2 directed therapies were delineated in the protocol. Participants were randomly assigned to receive C or none. Multidrug C for at least 4 courses was recommended. Drug selection was at the discretion of the investigator. Slow accrual led to premature closure of the trial before achieving the planned sample size of 265. Results The trial accrued 162 patients (C, 85; control, 77) from 2002–2010. The groups were balanced in regard to the characteristics listed in the table below. At a median follow up of 4.9 years, there were 24 (28%) DFS events and 9 (11%) deaths in the C group compared with 34 (44%) DFS events and 21 (27%) deaths in the control group, corresponding to a 5-year DFS of 69% vs. 57%, [DFS HR (C/control) = 0.59, 95% CI (0.35, 0.99)], p =0.046] and a 5-year OS of 88% vs. 76%, [OS HR (C/control) = 0.41, 95% CI (0.19, 0.89)], p =0.02]. The results remained significant for both DFS and OS in multivariable Cox proportional hazards modeling controlling for ILRR location, disease-free interval, ER status and prior adjuvant chemotherapy. Adjuvant C was particularly effective for women with ER-negative ILRR: 5-year DFS 67% vs. 35%, [DFS HR (C/control) = 0.32, 95% CI (0.14, 0.73)], p =0.007] and OS 79% vs. 69%, [OS HR (C/control) = 0.43, 95% CI (0.15, 1.24)], p =0.12]. Results for the ER-positive ILRR cohort were: 5-year DFS 70% vs. 69%, [DFS HR (C/control) = 0.94, 95% CI (0.47, 1.89)], p =0.87] and OS 94% vs. 80%, [OS HR (C/control) = 0.40, 95% CI (0.12, 1.28)], p =0.12]. Conclusion Adjuvant chemotherapy should be recommended for patients with completely resected isolated loco-regional recurrences of breast cancer, in particular, if the recurrence is not sensitive to endocrine therapy. Funding NCI PHS grants U10-CA-37377, -69974, -12027, -69651, CA-75362. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S3-2.