Abstract 4861: Chemotherapy improves overall survival in patients with T2N0M0 non-small cell lung cancer undergoing definitive radiation therapy: An analysis of the SEER database

Abstract

Abstract Objectives: Despite relatively routine practice and recommendations by clinical guidelines, an advantage of adding systemic chemotherapy to definitive radiation in patients with early stage non-small cell lung cancer (NSCLC) has never been demonstrated by randomized or large-scale studies. This study evaluates the role of chemotherapy in addition to thoracic radiation in T2N0M0 NSCLC patients who did not undergo surgical resection. Materials and Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database, we screened for patients with T2N0M0 NSCLC who received radiation therapy without surgical resection from 2004 to 2015. T-staging was defined according to the American Joint Committee on Cancer (AJCC) 6th (Year 2004+) and 7th(Year 2010+) versions. Kaplan-Meier curves and estimated overall survival according to chemotherapy status were determined by Log-rank test. Both univariate and multivariate analyses were conducted for the AJCC 6th (T2), 7th T2a, and 7th T2b groups. All the statistical analyses were performed using JMP software version 13 (SAS Institute, Cary, NC), and significance was achieved when P-value is below 0.05. Results: A total of 6,075 and 3,138 patients were identified for AJCC 6th (T2; 3cm -7cm) and 7th (T2a; 3 - 5cm, T2b; 5-7 cm) version, respectively. Administration of chemotherapy was associated with younger age, male sex, non-adenocarcinoma, and high pathologic grade. Kaplan-Meier estimates demonstrated that the chemotherapy group had a statistically significant longer five-year overall survival than the non-chemotherapy group in patients with AJCC 6th T2 (19.9% vs 15.8%, p=0.0023) and AJCC 7th T2b (5-7cm, 20.9% vs 13.6%, p=0.0046) but not those with AJCC 7th T2a (3-5cm, 24.3% vs 21.1%, p=0.4369). Multivariate analyses also revealed that the use of chemotherapy was an independent prognostic factor in AJCC 6th T2 and AJCC 7th T2b. Conclusions: This study strongly suggests that chemotherapy may benefit non-adenocarcinoma patients with primary tumor larger than 5cm (AJCC 8th T3) undergoing chest radiation. Citation Format: Takefumi Komiya, Gerard Chaaya, Emily Powell. Chemotherapy improves overall survival in patients with T2N0M0 non-small cell lung cancer undergoing definitive radiation therapy: An analysis of the SEER database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4861.