Prognostic Impact of Single and Multiple Descriptors in Pathologically Staged T3N0M0 NSCLC

T components of the current eighth edition of lung cancer American Joint Commission on Cancer (AJCC) staging assignment include size of primary tumor and others such as chest wall invasion. The role of the presence of multiple T3 descriptors in prognosis remains unknown.

Using the National Cancer Database and the AJCC seventh edition, pathologically staged (R0) N0M0 NSCLC cases diagnosed in 2010 to 2016 were analyzed. The selected cases had primary size larger than 5 cm or staged as T3 by the AJCC seventh edition despite the size of less than 5 cm. T3 descriptor status according to the eighth edition was defined as single descriptor ("T3-single") with primary size of 5 to 7 cm or size less than 5 cm and T3 based on the seventh edition ("T3-other") or multiple descriptor ("T3-multi") with presence of both descriptors. Survival analysis was performed with validation of multivariate analyses.

Of the 108,632 surgically resected pathologically staged N0M0R0 NSCLC cases, 9931 met the following criteria: 8955 as T3-single (4381 as T3-size, 4574 as T3-other) and 884 as T3-multi. Univariate and multivariate analyses revealed that T3-multi had significantly worse overall survival than T3-single with a median survival of 37.3 versus 69.3 months, respectively. Propensity score matching analysis validated the statistical significance. Exploratory analysis also revealed that the survival of the T3-multi group is similar to that of the T4 groups.

Our retrospective analysis using the National Cancer Database suggests that prognosis of patients with multiple T3 descriptors is substantially worse than those with single descriptors. Further research may be required to accurately define the prognosis of NSCLC for future staging update.