Smoking History as a Predictor of Pemetrexed Monotherapy in Patients with Non-Squamous Non-Small Cell Lung Cancer.

BACKGROUND

Pemetrexed monotherapy has come to be recognized as the standard of care for second-line therapy of non-squamous non-small cell lung cancer (NSCLC). Thymidylate synthase (TS) expression is recognized as a potential predictor of the response to pemetrexed-based chemotherapy in patients with advanced NSCLC. The purpose of this study was to identify useful predictors of the response to pemetrexed other than TS expression.

METHODS

The records of non-squamous NSCLC patients without driver mutations who received pemetrexed monotherapy as a second or later line of chemotherapy at Kitasato University Hospital between March 2009 and October 2015 were retrospectively reviewed, and the treatment outcomes were evaluated.

RESULTS

In the 116 patients with non-squamous NSCLC, the overall response rate and progression-free survival (PFS) were 10.3% and 2.1 months, respectively. The disease control rate and PFS differed significantly among current smokers and never-smokers/former light smokers (44.9 vs. 65.8%, and 1.8 vs. 4.0 months, respectively). Furthermore, multivariate analysis identified Eastern Cooperative Oncology Group Performance Status and smoking status as independent predictors of the PFS.

CONCLUSION

The clinical data obtained in this study may provide a valuable basis for the use of smoking status as a predictor of pemetrexed monotherapy in wild-type NSCLC patients.