Patients with early-stage (T1-2N0) adenosquamous lung cancer have worse long-term survival compared to patients with early-stage lung adenocarcinoma or squamous cell histology.

Abstract

8550 Background: Survival outcomes for patients with adenosquamous carcinoma of the lung are not well understood by virtue of reduced prevalence. The objective of this study is to compare the long-term survival among patients with adenocarcinoma, squamous cell carcinoma and adenosquamous carcinoma of the lung. Methods: Overall survival of all patients with adenosquamous carcinoma, squamous cell carcinoma, and adenocarcinoma who received guideline-concordant treatment for T1-2N0M0 from 2004-2017 in the National Cancer Data Base was assessed using Kaplan-Meier analysis, multivariable Cox proportional hazard analysis, and propensity score-matched analysis. Results: Among patients who met study criteria (N = 88,983), there were 2,469 (2.77%) patients with adenosquamous, 60,148 (67.59%) with adenocarcinoma and 26,366 (29.63%) with squamous cell carcinoma histology. In patients who had T1-T2 N0 M0 disease, adenosquamous carcinoma was associated with significantly worse 5-year overall survival (58.9% [95%CI:56.6%-61.1%]) when compared with adenocarcinoma (72.4% [95% CI:72.0%-72.8%]) and squamous cell carcinoma (62.6% [95% CI:61.9%-63.3%]). In multivariable Cox proportional hazards analysis, adenocarcinoma (HR 0.81 [95% CI:0.76-0.87], p < 0.001) and squamous cell carcinoma (HR 0.86 [95% CI:0.80-0.92], p < 0.001) continued to be associated with significantly better survival when compared to adenosquamous carcinoma histology. A propensity score-matched analysis of 1,854 adenocarcinoma and 1,854 adenosquamous patients who were well matched by 17 common prognostic covariates (including tumor size and comorbidities) found that adenosquamous histology (57.2% [95% CI:54.7%-59.6%]) was associated with worse survival when compared to adenocarcinoma (63.0% [95% CI:60.6%-65.4%]). An additional propensity score-matched analysis of 1,852 squamous cell carcinoma and 1,852 adenosquamous patients matched by the same covariates demonstrated that adenosquamous carcinoma (57.1% [95%CI:54.6%-59.6%]) was associated with worse survival when compared with squamous cell carcinoma (64.0% [95% CI:61.5%-66.4%]). Conclusions: Early stage adenosquamous carcinoma of the lung is associated with worse overall survival compared to its individual histologic components of adenocarcinoma or squamous cell carcinoma. These observations in both the unmatched and propensity matched patient cohorts invoke consideration of multimodality therapy for these early tumors.