Histology as a potential clinical predictor of outcome in advanced non-small-cell lung cancer treated with vinorelbine and mitomycin combination chemotherapy.

Background: The importance of clinical predictors in the treatment of non-small-cell lung cancer (NSCLC) has increased during the last decade. This retrospective study analyzed the combined patient-level data from two phase II trials that investigated the efficacy and safety of combination chemotherapy with vinorelbine and mitomycin in patients with locally advanced or metastatic NSCLC. The aim of this analysis was to determine if patients' baseline and disease characteristics, including histology, gender, smoking history, and expression of TTF-1, might be potential predictors of outcome.
Methods: Response rates, unadjusted survival times, and Cox covariate-adjusted hazard ratios (HRs) were calculated. Results were reported separately for each subgroup in each individual trial and in the pooled data set.
Results: A total of 175 patients were included in this analysis. Adjusted HRs for both overall survival (OS) and progression free survival (PFS) favored the nonadenocarcinoma histology subgroup, achieving a statistical significance for OS in the pooled data (n = 175; HR 0.68; 95 % CI 0.49-0.94; p = 0.019). TTF-1-negative immunohistochemistry was associated with a significantly higher response rate (25 vs. 0 %; p = 0.04) and with a nonsignificant advantage in OS (n = 33; HR 1.23; 95 % CI 0.56-2.73; p = 0.608). Gender and smoking history were not strongly related to outcome.
Conclusions: The results of this analysis indicate that patients with nonadenocarcinoma histology might get superior benefit from combination chemotherapy with vinorelbine and mitomycin. These results should be confirmed in a prospective study.