Surgical management associates independently with improved survival among de novo stage IV breast cancer patients without liver or brain metastasis.

Abstract

e12106 Background: To examine the independent effect of surgical management of the primary tumor and axillary lymph node on survival in patients with de novo Stage IV breast cancer (BC) Methods: 113 patients with de novo stage BC between 2010 to 2013 were followed up to Oct. 1, 2016. Multivariable Cox proportional hazard models were constructed to assess the effect of mastectomy (MAS) and axillary lymph node dissection (ALND) on overall survival (OS) after univariate analyses and K-M curves. Non-treatment covariates included age, BMI, menopause, Stage T, Stage N, ER, PR, HER2, Ki67>14% status, and metastasis sites (lung, liver, bone, brain and others). Chemotherapy, hormonal, target treatement and radiotherapy before the disease progression were others. Results: Mean age 52 (24 - 84) years old, metastasis site by bone 53% (60), lung 32% (36), liver 32% (36), brain 2% (2), and other 23% (23). Median survival 21.4 months. All 42% (48) surgical patients had simultaneous MAS and ALND. Younger (mean 49 vs. 54) and fewer post-menopause (42% vs. 62%) were significantly noticed in surgical patients with median survival 37.8 vs. 14.2 months of others. Multivariable analysis showed OS favorable HRs 0.53 (95% CI 0.24 - 1.17, p=0.12) of surgery and HR 0.48 (0.22 - 1.04, p=0.06) of hormonal drug, and significant HR 0.10, (0.02 - 0.52, p<0.01) of target therapy, insignificant effects of chemotherapy HR 0.60(0.26 - 1.42, p=0.25) and radiotherapy HR 0.70 (0.33 - 1.50, p =0.36). Unfavorable metastasis sites were identified as brain and liver at multivariable model for subgroup analysis. K-M curves estimated median survival 29.3 vs. 14.4 months (favorable vs. unfavorable patients). Both univariate and multivariate analyses showed the significant effect of surgery in favorable subgroup (N=76) with HR 0.30 (0.16 - 0.56, p <0.01) and 0.33 (0.11 - 0.98, p=0.05) on OS, respectively. In unfavorable subgroup (N=37), the results were insignificant effect of surgery on OS with HR 0.75 (0.37 - 1.55, p=0.54) and 1.60 (0.33 - 7.81, p=0.56). Conclusions: Surgical management associated independently with improved survival among de novo stage IV BC patients without liver or brain metastasis.