Impact of clinical and pathological variables on stage I non-small cell lung cancer outcomes.

Abstract

e21071 Background: Stage I patients (pts) have 5-year survival ranging 50-75% suggesting heterogeneity within. While American Joint Committee on Cancer 8th edition upstages tumors with visceral pleural invasion (VPI) to IB, other histological features namely lymphovascular invasion (LVI), micropapillary pattern (MIP), spread through airspace (STAS) & neuroendocrine differentiation (NE) may also affect prognosis. This retrospective single institution study evaluated influence of these factors along with pt variables age, gender, smoking, Charleston comorbidity index (CCI) & chemotherapy (CT) on recurrence & mortality. Methods: 351 resected stage I cases from 2015-2019 were included. Data was summarized as means (standard deviation/SD) or percentages. Association between variables & outcomes (measured from diagnosis till event or last visit if no event) were investigated using Univariate & Multiple Cox proportional hazards models. Survival curves were compared using the Log-Rank test when the assumption for the proportional hazards was not satisfied. All predictors were included in the multiple Cox regression models based on their clinical importance. P < 0.05 was considered statistically significant. SAS 9.4 (SAS Institute, Cary, NC) was used for the analysis. Results: Mean age was 69.62 years (9.83). Majority were female (57.3%), smokers (76.9%), & had adenocarcinoma (AC) (78.6%). 39% had COPD & mean CCI was 6.3 (1.74). 193 (55%) pts had lobectomy or larger procedure while 158 (45%) had sub-lobar resection. 45 (12.8%) pts received CT. Recurrence & death occurred in 33 (9.4%) & 15 (4.3%) pts respectively. Univariate models indicated higher recurrence risk with NE (HR = 4.18 95% CI 1.47-11.9, p = 0.0075), LVI (HR = 2.68, 95% CI 1.03-6.94, p = 0.0423), COPD (HR = 3.28 95% CI 1.56-6.9, p = 0.0017), age (HR = 1.05 95% CI 1.01-1.09, p = 0.0212), & CCI (HR = 1.57 95% CI 1.35-1.83, p < .0001). CT was also associated with increased recurrence risk (HR = 8.61, 95% CI 4.28-17.33, p < .0001). Multivariable model for recurrence retained significance for CT & CCI. Age (HR = 1.07 95% CI 1.01-1.14, p = 0.0312), CCI (HR = 1.27 95 % CI 1.02-1.59, p = 0.0347) were associated with mortality in univariate models. Multivariate analysis for mortality wasn’t feasible due to few events. Conclusions: Histological features other than VPI may be associated with recurrence. Pts who received CT had increased recurrence but they possibly had multiple risk factors or other adverse features not assessed here. Limitations included retrospective nature, limited sample size & small number of events.