Thyroid Transcription Factor-1 Expression in Advanced Non-Small Cell Lung Cancer: Impact on Survival Outcome

Background: The prognostic role of thyroid transcription factor-1 (TTF-1) expression in lung cancer has been assessed but with inconsistent results. The present study aimed to evaluate the prognostic value of TTF1 expression in advanced non-squamous non-small cell lung cancer (NSCLC). Materials and Methods: In this retrospective study, patients with stage IIIB-IV non-squamous NSCLC were enrolled. Progression free survival (PFS) and overall survival (OS) were assessed according to TTF1 expression status, age categories (${\leq}60$ vs >60 years), gender, performance status (PS) (0-2 vs 3-4), type of 1st line chemotherapy (pemetrexed containing vs others) and EGFR status. Results: A total of 120 patients were included. In univariate analysis, PFS was improved in patients with PS 0-2 (7.0 vs 2.0 months, p=0.002) and those who received pemetrexed-containing chemotherapy (9.2 vs 5.8 months, p=0.004). OS was improved in female patients (23.0 vs 8.7 months, p<0.0001), PS 0-2 (14.4 vs 2.0 months, p<0.0001), those with pemetrexed-containing chemotherapy (17.0 vs 11.0 months, p=0.019), TTF1-positive (12.8 vs 5.8 months, p=0.011) and EGFR- mutant patients (23.0 vs 11.7 months, p=0.006). In multivariate analysis, male gender (HR=2.34, p=0.025) and non-pemetrexed containing therapy (HR=2.24, p=0.022) were independent predictors of worse PFS. Wild EGFR status (HR=2.49, p=0.015) and male gender (HR=2.78, p=0.008) were predictors of worse OS. Conclusions: Pemetrexed-containing therapy significantly improved PFS while OS was improved in EGFR mutant patients. Female patients had better PFS and OS. TTF1 expression was not a prognostic marker in advanced non-squamous NSCLC.