Impact of institutional experience on survival outcome of patients undergoing combined chemoradiation therapy for inoperable non-small-cell lung cancer

Purpose: Clinical experience of both physicians and institutions has been shown to significantly influence the outcome of patients. We conducted this retrospective cohort study to examine its impact on the outcome of patients undergoing combined chemoradiation therapy for the treatment of locally advanced inoperable non-small-cell lung cancer. Methods and Materials: We compared the clinical data from 239 patients who were enrolled in two consecutive Radiation Therapy Oncology Group (RTOG) trials (RTOG 91-06, RTOG 92-04) according to the number of patients enrolled from each institution in either trial alone or the two trials combined.Results: Overall, patients treated at the institutions that enrolled ≥5 patients survived longer than those treated at the institutions that enrolled <5 patients (median survival 20.5 vs. 13.4 months, p = 0.0006) with a more than doubling of the 2- and 3-year survival rates (45% and 31% vs. 20% and 13%, respectively). Multivariate analyses confirmed that the number of patients enrolled from each institution was an important prognostic factor for the entire group (p = 0.001) and also for RTOG 91-06 (p = 0.05) and RTOG 92-04 (p = 0.004) when the data were analyzed separately. Conclusion: Institutional experience has a significant impact on the survival outcome of patients undergoing combined chemoradiation therapy for inoperable non-small cell lung cancer.