Understanding clinical practice and survival outcomes in patients with unresectable stage III non-small-cell lung cancer in a single centre in Quebec

Methods A retrospective cohort study considered patients 18 or more years of age diagnosed between January 2007 and May 2018 with unresectable stage iii non-small-cell lung cancer (NsCLC) who received combined chemoradiation (CRT). Survival was analyzed using the Kaplan-Meier method to determine median overall (OS) and progression-free survival (PFS) and the associated 95% confidence intervals (CIS). Cox regression analysis was performed to identify factors prognostic for survival, including age, sex, smoking status, Eastern Cooperative Oncology Group performance status (ECOG PS), histology, treatment type, tumour size, and nodal status. Results Of 226 patients diagnosed with unresectable stage iii disease, 134 (59%) received combined CRT. Mean age was 63 years; most patients were white, were current smokers, had an ECOG PS of 0 or 1, and had nonsquamous histology. Median PFS was 7.03 months (95% CI: 5.6 months to 8.5 months), and os for the cohort was 18.7 months (95% CI: 12.4 months to 24.8 months). Of those patients, 78% would have been eligible for durvalumab consolidation therapy. Univariate analysis demonstrated a significant os benefit (p = 0.010) for concurrent CRT (CCRT) compared with sequential CRT (SORT). Disease-specific survival remained significantly better in the ccRT group (p = 0.004). No difference in PFS was found between the ccRT and scRT groups. In addition, tumour size and nodal involvement were significant discriminating factors for survival (p < 0.05). In this patient cohort, 64% of patients progressed and received subsequent therapy. Based on multivariate analysis, tumour size and nodal station were the only factors predictive of survival in patients with unresectable stage III NSCLC treated with CRT. Conclusions Combined CRT has been the standard treatment for unresectable stage III NSCLC. In our study, a trend of better survival was seen for CCRT compared with sCRT. Factors predictive of survival in patients with stage III disease treated with CRT were tumour size and nodal station. Most patients with stage III disease would potentially be eligible for durvalumab maintenance therapy based on the eligibility criteria from the PACIFIC trial. The use and effectiveness of novel treatments will have to be further studied in our real-world patient population and similar populations elsewhere.