OA06.03 PL1/2 Status is Associated With Worse Survival in T2 Non-Small Cell Lung Carcinoma: Is There A Need for a New Subgroup in the T Classification?

Abstract

In the current staging system visceral pleural invasion is well positioned as a T2 descriptor and confers a worse prognosis.Also, when the tumor diameter is between 3 and 5 cm it is staged as T2. Among T2 category, PL1 was defined as tumor invades beyond the elastic layer of the visceral pleura, whereas in PL2, tumor invades to the visceral pleura surface.Although those two subcategories represent same T2 grouping we aimed to analyze whether tumors with PL1 and PL2 involvement deserve another subgroup classification? Between 2003 and 2019, among 804 patients underwent resectional surgery for non-small cell lung cancer(NSCLC) and 203(25.2%) of the patients were considered to have T2 tumor. Among those PL1-2 reported in 132 patients (65.0%)(Group 1) and no pleural invasion(i.e.PL0) was disclosed in 71 patients(35.0) (Group 2). Patients were followed up at a mean of 38 months(1 to 164 months). Survival of patients were analyzed using Kaplan-Meier analysis, log-rank test and multivariate analysis was accomplished using Cox-analysis. The patients with PL1/PL2 T2 tumor had a mean of 122 months (95% Confidence Interval: 106 to 138 months) of survival time whereas it was 159 months (95% CI: 140 to 179 months) in those with PL0 T2 tumor (p=0,016)(Figure). N factor, and presence of PL1/PL2 were found to be independently associated with survival(p=0.04 and 0.03 respectively). PL1/PL2 involvement seems to be independently associated with worse survival and represents a different subgroup in patients with T2 NSCLC. It seems plausible to suggest that PL1-2 status could be considered as a new subgroup in T2 such as T2c.