Radiation dose and survival of patients with stage IV non-small cell lung cancer undergoing concurrent chemotherapy and thoracic three-dimensional radiotherapy: reanalysis of the findings of a single-center prospective study

BACKGROUND: The objective of this study was to evaluate the radiation dose and response in terms of local-regional progression-free survival (LRPFS) and overall survival (OS) of patients with stage IV non-small cell lung cancer (NSCLC) undergoing concurrent chemotherapy and thoracic three-dimensional radiotherapy. METHODS: In all, we enrolled 201 patients with stage IV NSCLC in this study and analyzed OS in 159 patients and LRPFS in 120. RESULTS: The 1-, 2-, 3-, and 5-year OS rates were 46.2%, 19.5%, 11.7%, and 5.8%, respectively, the median survival time being 12 months. The median survival times in differential treatment response of primary tumors were 19 of complete response, 13 of partial response, 8 of stable disease, and 6 months of progressive disease, respectively (P = 0.000). The 1-, 2-, 3-, and 5-year LRPFS rates of patients undergoing four to five cycles with doses ≥63 Gy and <63 Gy were 77.4% and 32.6%, 36.2% and 21.7%, 27.2% and 0, and 15.9% and 0, respectively (P = 0.002). According to multivariate analyses, four to five cycles of chemotherapy, gross tumor volume <175.00 cm(3) and post-treatment Karnofsky Performance Status score stable or increased by at least 10 units were independent prognostic factors for better OS (P = 0.035, P = 0.008, and P = 0.000, respectively). Radiation dose to the primary tumor ≥63 Gy resulted in better OS (P = 0.057) and LRPFS (P = 0.051), both findings being of borderline significance. CONCLUSIONS: Treatment of IV NSCLC with joint administration of four to five cycles of chemotherapy and three-dimensional radiotherapy may prolong survival, particularly in patients receiving ≥63 Gy radiotherapy, with gross tumor volume <175.00 cm(3) and post-treatment Karnofsky Performance Status score not lower than pretreatment values.