Purpose: For the definitive treatment of stage III NSCLC, the optimal chemotherapy regimen to use with radiation is not clearly defined. Using a large cohort of patients treated across VHAs, we compare the outcome of patents treated with cisplatin and etoposide (EP) vs those treated with carboplatin and paclitaxel (CP).
Methods: Using the VA Central Cancer Registry, patients with stage III non-small cell lung cancer (NSCLC) diagnosed between 2001 and 2010 were identified. For analysis, patients were included if concurrent chemoradiotherapy was initiated within 4 months of diagnosis and excluded if treated with surgery or sequential chemoradiotherapy (ie, chemotherapy was not started within 7 days of the start of radiotherapy).
Results: Out of 17,010 patients identified, 1,856 patients were eligible for analysis of which 28% (n = 565) received EP. In multivariable analysis, the use of EP was not associated with any survival advantage (HR 0.88; 95% CI 0.79-0.99; P = .0254). In a propensity score analysis that matched 382 patients treated with EP with the same number of patients treated with CP, there was no survival advantage for EP (HR 0.96; 95% CI 0.83-1.11; P = .5572). Subsequently, a multivariate model weighted on the inverse propensity for being treated with EP was fitted and similarly showed no survival advantage for EP (HR 0.95; 95% CI, 0.84-1.08; P = .4525). Finally, an instrumental variable analysis was used to compare matched patients between 8 VHAs that were “EP-encouraged” (ie, > 50% received EP, mean 71.1%) with 11 VHAs that were “EP-discouraged” (ie, < 10% received EP, mean 2.8%). This analysis found no survival advantage for EP (HR 1.06; 95% CI, 0.90-1.26; P = .4766). When adverse events were compared with CP, patients treated with EP had increased hospitalization (2.4 vs 1.7, P < .01), outpatient visits (17.6 vs 12.6, P <.01), infectious complications (47.6% vs 39.6%, P < .0001), acute renal failure (30.3 vs 21.3%, P <.0001), and mucositis/esophagitis (18.7 vs 14.5%, P = 0.0251).
Conclusions: After accounting for various prognostic variables, matched cohorts, and regional differences, there were no differences in survival between patients treated with EP and CP; however, EP was associated with increased morbidity.
