Radiotherapy Dose and Induction Chemotherapy Cycles Are Associated With Prognosis and Toxicity Risk: A Retrospective Study of 227 Patients With Unresectable Stage III Non-Small-Cell Lung Cancer

OBJECTIVE: Concurrent chemoradiation (cCHRT) has been confirmed as the standard treatment for local advanced non-small-cell lung cancer (NSCLC). This study is to assess the appropriate timing of radiotherapy and cycles of induction chemotherapy for those patients. METHODS: 227 inoperable stage III NSCLC patients were selected, we analyzed the potential prognostic factors and the influence of induction chemotherapy was evaluated. RESULTS: The median survival time was 20.7 months; only 25 patients chose chemotherapy alone (11.0%), 137 patients underwent sequential chemoradiation (sCHRT, 60.4%), and 65 patients received cCHRT (28.6%). Multivariate analyses showed radiation therapy (P = 0.001), the Eastern Cooperative Oncology Group (ECOG) score (P = 0.000) and the lymph node stage (P = 0.001) were independent prognostic factors. cCHRT was not found to be superior (P = 0.330). We selected patients received 60-66 Gy and found the cCHRT groups achieved a relatively better outcome, with a median Overall Survival (OS) of 25.2 months vs 20.1 months in the sCHRT group (P = 0.019). We also found cycles of induction chemotherapy did not compromise survival; however, ≥3 cycles resulted in more grade 3-4 hematology toxicities, with a proportion of 18/99 compared with 53/103 among patients who underwent ≤3 cycles. In addition, higher grade hematology toxicities and poor ECOG were also the most common reasons for abandoning cCHRT. CONCLUSIONS: For inoperable stage III NSCLC, cCHRT showed its superiority only when the radiotherapy dose was 60-66 Gy. Cycles of induction chemotherapy did not interfere with survival; however, ≥3 cycles resulted in more grade 3-4 hematology toxicities, leading to the cessation of cCHRT.