Phase II study of low-dose paclitaxel with timed thoracic radiotherapy followed by adjuvant gemcitabine and carboplatin in unresectable stage III non-small cell lung cancer

Objectives: The purpose of the proposed study is to evaluate the effectiveness and safety of low-dose paclitaxel with timed thoracic radiotherapy (TTR) for local control by inducing maximum radiosensitization through G2-M phase cell cycle arrest, followed by full dose adjuvant chemotherapy with gemcitabine and carboplatin for eradication of possible micrometastasis in unresectable stage III non-small cell lung cancer (NSCLC). Materials and methods: This is a single-center, non-randomized prospective phase II study. Patients with unresectable stage III NSCLC were treated with paclitaxel 15mg/m² IV, followed by TTR 6h later on Monday/Wednesday/Friday, and TTR only on Tuesday/Thursday mornings (total 55Gy). Full dose adjuvant chemotherapy consisted of intravenous carboplatin (AUC 5) on day 1, gemcitabine 1000mg/m² on days 1 and 8, every 21 days for 4 cycles. The primary endpoint was overall survival (OS). Secondary endpoints were overall response rate (ORR), and toxicities. Results: Twenty-seven patients were eligible for the study. Patient characteristics were: 19 males (70%); median age 67 years (range 39-82); 15 (56%) stage IIIB; 89% with ECOG performance status ≥1. Three-year OS was 16.7% in all patients, and 27.3% in patients received three or more cycles of adjuvant chemotherapy, respectively. ORR was 63%. Grade 3 toxicities during paclitaxel plus concurrent TTR phase were radiation esophagitis (11%) and radiation pneumonitis (4%), no grade 4 toxicities occurred. One grade 5 hemoptysis. Grade 3/4 toxicities during adjuvant gemcitabine/carboplatin were pneumonitis (22%), anemia (30%), neutropenia (22%), and thrombocytopenia (33%), one grade 5 neutropenic fever. Conclusion: Low-dose paclitaxel with concurrent TTR is an effective chemoradiotherapy regimen in unresectable stage III NSCLC. Improved survival benefit was observed in patients who have received three or more cycles of full dose adjuvant chemotherapy, yet, gemcitabine related radiation pneumonitis and hematological toxicities limited adjuvant chemotherapy delivery.