Survival Benefit of Perioperative Systemic Chemotherapy for Patients With N0 to N1 NSCLC Having Synchronous Brain Metastasis

Introduction: In stage IV NSCLC with solitary or oligometastatic brain metastasis, surgical resection of the primary and definitive management of the brain metastasis is an accepted standard. However, the effect of systemic chemotherapy after surgical resection on overall survival is not well-established. Methods: We used the National Cancer Database to retrospectively identify individuals with NSCLC as the primary tumor along with synchronous brain metastases who underwent thoracic resection with or without adjuvant chemotherapy. Chi-square and Wilcoxon rank sum tests were performed to compare categorical and continuous variables, respectively, across the treatment groups. Kaplan-Meier and Cox proportional modeling were done to determine the survival benefit. Results: A total of 310 (71.9%) of the cohort received perioperative chemotherapy, most of whom (79.4%) received it in the adjuvant setting. Patients receiving chemotherapy were likely to be younger (p = 0.002), privately insured (p = 0.01), and receive radiation (p < 0.001). Perioperative chemotherapy was significantly associated with survival on both univariate (hazard ratio = 0.71[0.52 – 0.99]) and multivariable (hazard ratio = 0.66 [0.47 – 0.92]) in addition to age (p = 0.03), Charlson-Deyo score (p = 0.02), pathologic N stage (p = 0.02), and adenocarcinoma histology (p = 0.02). Kaplan-Meier analysis confirmed this result with a significantly better survival with perioperative chemotherapy (p = 0.02). Further subgroup analysis using pathologic N stage revealed similar effect in pN1 (p = 0.001), but not pN0 (p = 0.2) patients. Conclusions: Perioperative chemotherapy for pN0-1 NSCLC with synchronous brain metastasis is associated with improved OS in this analysis.