Effect of three-dimensional radiotherapy on the survival of patients with stage IV squamous cell lung cancer

Abstract

Objective To retrospectively analyze the effect of three-dimensional radiotherapy on the survival of patients with stage Ⅳ squamous cell lung cancer. Methods Of the 101 patients collected from two prospective phase Ⅱ studies, 88 were part of the per-protocol set. All patients received platinum-doublet chemotherapy with concurrent radiation to the primary tumor. Primary endpoints were overall survival (OS) and progression-free survival (PFS). Survival was calculated using the Kaplan-Meier estimator, and univariate and multivariate analyses were performed using the log-rank test and Cox model, respectively. Results The 1-, 2-, 3-, and 5-year OS rates of the 88 patients were 42.2%, 13.6%, 8.7%, and 3.1%, respectively, and the median survival time (MST) was 10 months. The 1-, 2-, 3-, and 5-year OS and MST at PTV dose ≥63 Gy were 45.7%, 25.7%, 17.1%, 7.1%, and 11 months, respectively, whereas the 1-, 2-, 3-, and 5-year OS and MST at PTV dose<63 Gy were 39.6%, 4.5%, 2.8%, 0%, and 10 months, respectively (P=0.007). The median PFS at ≥63 Gy and<63 Gy were 9 months and 7 months, respectively (P=0.032). The 1-, 2-, 3-, and 5-year OS and PFS of patients who received 4 cycles of chemotherapy at a PTV dose of ≥63 Gy were 51.9%, 29.6%, 18.5%, 9.9%, and 9 months, respectively (P=0.001 and P=0.012), which were significantly prolonged compared with other treatment modalities. Multivariate analysis showed that PTV ≥63 Gy may be influence the OS of patients (P=0.080). Conclusions Three-dimensional radiotherapy can prolong the survival of patients with stage ⅠV squamous cell lung cancer, as demonstrated by the gradual improvement in OS and PFS following the increase in the intensity of concurrent chemotherapy and radiation therapy. A PTV dose of ≥63 Gy may be influence the OS. Key words: Lung neoplasms/three-dimensional radiotherapy; Prognosis