P3.16-45 The Rates and Survival of Surgically-Resected Second Primary Lung Cancers in Patients Undergoing Resection of an Initial Primary Lung Cancer.

Abstract

The Lung Cancer Screening Trial demonstrated improved overall survival (OS) and lung cancer specific survival (LCSS), likely due to finding early-stage non-small cell lung cancer(NSCLC). Patients with a past history of lung cancer were excluded from this trial. The purpose of our investigation is to suggest whether long-term surveillance strategies (4 years after surgical resection of the initial lung cancer(1LC)) would be beneficial in NSCLC patients by assessing the rates of second lung cancers(2LC) and the OS/LCSS in 1LC as compared to 2LCs when treated surgically. The SEER13/18 database was retrospectively reviewed for years 1998-2013. The 1LC population(N=58,758) consisted of all patients with Stage I-III (AJCC 6th) NSCLC undergoing a definitive resection, while the 2LC population (N= 384) consisted of 1LC patients who developed a 2LC > 48 months after 1LC. Log-rank tests were used to determine the OS/LCSS differences between the 1LC and 2LC in the entire surgical group(EG) and in those having an early-stage tumors (ESR, tumors <4cm with no node involvement). Joinpoint analysis was used to assess changes in rates of 2LCs in comparison to all other second cancers after resection of a 1LC. Median follow-up in the 1LC and SLC populations was 76 and 46 months. The rate of 2LCs was significantly less than all other second cancers until 2001 when the incidence of 2LCs increased sharply and became significantly greater than all other second cancers in females starting in year 2005 and in men starting in year 2010. OS/LCSS, adjusted for propensity score by using inverse probability weighting, demonstrated similar OS, but worse LCSS for 2LCs in the EG, but similar OS/LCSSs in the ESR group. Unlike the 1LC group, OS in the 2LC group was not dependent upon T/N stage, age, resection type, and race. OS in the 1LC and 2LC decreased with divorce, positive nodes, and poor differentiation. Because the rate of 2LCs are increasing and because the OS/LCSS of the 1LC and 2LC are similar in early-stage lesions, we feel that continued surveillance of patients in order to find early-stage disease may be beneficial.