Impact of Histologic Subtyping on Outcome in Lobar vs Sublobar Resections for Lung Cancer A Pilot Study

OBJECTIVE: The 2011 International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) classification of pulmonary adenocarcinomas introduces adenocarcinoma in situ and minimally invasive carcinoma and categorizes adenocarcinoma with more extensive invasion by the predominant subtype. Data have shown that wedge or segmentectomy (W/S) may be appropriate for in situ and minimally invasive adenocarcinoma, but whether sublobar resection is appropriate for tumors with more extensive invasion is unclear. The aim of this pilot study is to evaluate whether there are any trends regarding the impact of invasion and subtypes of carcinoma regarding survival in lobectomy vs W/S procedures using a comprehensive histologic evaluation. METHODS: Eighty-five surgical specimens (59 lobectomies, 26 W/Ss) were reviewed. Histologic type, size, pleural, lymphovascular invasion, and necrosis were recorded. Adenocarcinomas were classified by 2011 IASLC/ATS/ERS guidelines with each histologic pattern recorded as a percentage of the total tumor. Statistical analysis was performed using SAS, version 9.2. Proportional hazards regression analysis was used to evaluate survival according to resection type (lobectomy or W/S) adjusting for tumor size and the predominant histology. RESULTS: Multivariate analysis did not show a statistically significant difference in survival between lobectomy and W/S specimens adjusting for tumor size, regardless of histologic subtype or other negative predictors of prognosis (P = .7704). CONCLUSIONS: Our findings corroborate the prognostic significance of the 2011 adenocarcinoma subtyping classification and additionally suggest that lobectomy does not off er an overall survival advantage over W/S regardless of histologic subtype. Therefore, this finding suggests that limited resection may be appropriate for small size tumors, particularly those <= 2 cm with invasive histology.