A prospective analysis of surgery and survival in stage IV breast cancer (TBCRC 013).

1006 Background: TBCRC 013 is a multicenter prospective registry study evaluating the role of surgery for the primary tumor in de novo Stage IV disease. Methods: From 7/09-4/12, 127 pts from 14 sites were enrolled in 2 cohorts (A: Stage IV with intact primary (n = 112); B: metastases within 3 mos of primary surgery (n = 15)). All patients received 1st-line systemic therapy per treating physician. In Cohort A, patients classified as responders to 1st-line therapy (partial, complete, or stable distant disease) were referred to discuss elective surgery. Patient and tumor characteristics, response to systemic therapy and surgery of the primary tumor were correlated with 3yr overall survival (OS) using log rank, Kaplan Meier and Cox regression. Results: Among 112 pts in Cohort A, median pt age was 51yrs (21-77), median primary tumor size 3.2cm (0.8-15cm), median follow-up 54 mos (range 34-78). Subtypes were ER+HER2-, 71 (63%); ER+HER2+, 24 (21%); ER-HER2+, 9 (8%); ER-HER2-, 8 (7%). 3yr OS was 70% (95%CI, 63-79). 94 (85%) patients were classified as responders; 3 yr OS responders vs. non-responders, 78% (95%CI,70-87) vs 24% (95%CI,10-55), p < 0.001. Among responders, 39 (41%) chose surgery with no impact on 3y OS (77% with vs 76% without surgery, Table). Patients who chose surgery had larger tumors (3.8cm vs 3.2cm, p = 0.01), were more likely to have single organ metastatic disease (77% vs 41%, p = 0.001) and to have received 1st-line chemotherapy (39% vs 17%, p = 0.002). Among responders, surgery was not associated with improved survival for any subtype (ER+HER2-, p = 0.37; ER+HER2+, p = 0.07; ER-HER2+, p = 0.51; ER-HER2-, sample too small). Conclusions: In this prospective registry study of de novo Stage IV breast cancer, 3yr OS is 70%. The majority of patients responded to 1st-line therapy and 3yr OS was far superior among responders than non-responders. Among responders, surgery did not impact OS irrespective of tumor subtype. These data suggest caution in selecting patients for local therapy outside of clinical trials. Clinical trial information: NCT00941759.Responders Surgery N Median Survival, mos (95%CI) 3yr OS (95%CI) p All N 51 71 (56-NR) 76 (66-89) 0.85 Y 39 77 (52-NR) 77 (65-91) ER+ N 46 71 (56-NR) 78 (67–91) 0.47 Y 34 77 (53-NR) 79 (67-94) HER2+ N 12 NR (NR-NR) 83 (65-100) 0.39 Y 15 77 (77-NR) 100 (100-100)