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.