Value of TTF‑1 expression in non‑squamous non‑small‑cell lung cancer for assessing docetaxel monotherapy after chemotherapy failure

Docetaxel is one of the standard second/third-line treatments for non-small-cell lung cancer (NSCLC) following a failed response to prior cytotoxic chemotherapy. The predictive biomarker for the effectiveness of docetaxel therapy remains undetermined. However, thyroid transcription factor-1 (TTF-1) is known to be a good prognostic factor for a variety of chemotherapies. To investigate the association between TTF-1 expression and docetaxel monotherapy outcome, 82 patients with non-squamous NSCLC who received second/third-line docetaxel monotherapy were retrospectively screened. All backgrounds were well-balanced whether or not tumor TTF-1 was expressed, and the present clinical outcomes were similar to those reported by previous clinical studies. A better clinical outcome was indicated in TTF-1 positive compared with TTF-1 negative patients, with disease control rates of 69% vs. 42%, respectively (P=0.03) and median overall survival of 393 days vs. 221.5 days, respectively (P<0.01). Furthermore, progression free survival tended to be longer in TTF-1 positive compared with TTF-1 negative patients (median, 100 days vs. 67 days; P=0.09). Multivariate analysis revealed that TTF-1 positivity was a unique significant predictor for assessing overall survival after docetaxel monotherapy. TTF-1 positivity may be useful for predicting survival outcome in patients who received docetaxel monotherapy after failure of prior chemotherapy.