Effect of primary tumor surgery on prognosis of female patients with advanced triple negative breast cancer: a retrospective study based on SEER database

Abstract

Objective To analyze the effect of primary tumor surgery on the survival of female patients with advanced triple-negative breast cancer (TNBC) and related prognostic factors. Methods Totally 1 770 female patients primarily diagnosed with advanced TNBC from 2010 to 2016 were identified in the Surveillance, Epidemiology and End Results (SEER) database of U. S. National Cancer Institute for a retrospective study. Among them, 795 patients received primary tumor surgery and 975 patients underwent no surgery. Using propensity score matching (PSM) to balance confounding factors, Kaplan-Meier curve was used to calculate the overall survival (OS) and the disease-specific survival (DSS); Log-rank test and Cox regression analysis were used to evaluate the effect of different clinicopathological factors on the prognosis of female patients with advanced TNBC. Using R×64 3.5.2 software, the survival curve was drawn. Results All 1 770 patients with advanced TNBC were followed up for median 10 months (range: 0-83 months), with median overall survival of 13 months. The 2-year OS was 25.3% and the 3-year OS was 15.4%. The median OS was 18 months in operation group and 9 months in non-operation group, indicating a significant difference (χ2=181.380, P<0.001). The median DSS was 18 months in operation group and 10 months in non-operation group, indicating a significant difference (χ2=163.674, P<0.001). There was only N stage presented a significant statistic difference after PSM (χ2=22.712, P<0.001). Cox regression analysis showed that primary tumor surgery (OS: HR=0.544, 95%CI: 0.478-0.620, P<0.001; DSS: HR=0.560, 95%CI: 0.490-0.640, P<0.001), T-stage (OS: HR=1.166, 95%CI: 1.095-1.241, P<0.001; DSS: HR =1.177, 95%CI: 1.103-1.256, P<0.001), bone metastasis (OS: HR=0.802, 95%CI: 0.702-0.916, P=0.001; DSS: HR =0.788, 95%CI: 0.687-0.904, P<0.001), brain metastasis (OS: HR=0.593, 95%CI: 0.468-0.752, P<0.001; DSS: HR=0.571, 95%CI: 0.449-0.726, P<0.001), liver metastasis (OS: HR=0.590, 95%CI: 0.511-0.682, P<0.001; DSS: HR=0.587, 95%CI: 0.506-681, P<0.001) and chemotherapy (OS: HR=0.377, 95%CI: 0.322-0.443, P<0.001; DSS: HR=0.395, 95%CI: 0.334-0.467, P<0.001) were independent prognostic factors for the OS and DSS in advanced TNBC patients. Age was an independent prognostic factor for the OS(OS: HR=1.141, 95%CI: 1.039-1.254, P=0.006). Survival curve showed that operation group had more significant survival benefit compared with non-operation group before PSM (OS: χ2=181.380, P<0.001; DSS: χ2=163.674, P<0.001) and after PSM (OS: χ2=69.234, P<0.001; DSS: χ2=59.906, P<0.001). Conclusion The primary tumor surgery can improve the OS and DSS in female patients with advanced TNBC, which may provide some references for their clinical treatment. Key words: Breast neoplasms; Neoplasm metastasis; Mastectomy; Prognosis; Risk factors; SEER program