[A Phase I/II Study of Chemotherapy Concurrent with Twice-daily Radiotherapy Schedules by Intensity Modulated Radiation Therapy Using Simultaneous Integrated Boost for Limited-stage Small Cell Lung Cancer].

BACKGROUND: Twice-daily radiation concurrent with chemotherapy is one of the standard methods for limited-stage small cell lung cancer. The study was to evaluate the feasibility of chemotherapy concurrent with dose-escalating twice-daily radiotherapy by simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) approach in patients with limited-stage small cell lung cancer.

METHODS: Patients with limited-stage small cell lung cancer were included, treated with twice-daily radiotherapy by SIB-IMRT concurrent with chemotherapy of etoposide plus cisplatin. Dose escalation was conducted by "classical" 3+3 methods with three patients enrolled in each dose level. The therapeutic gross tumor volume (GTV) was treated according to three consecutive dose levels i.e., 45 Gy at 1.5 Gy twice daily, 50 Gy at 1.67 Gy twice daily and 54 Gy at 1.8 Gy twice daily. The planning target volume (PTV) received a dose of 45 Gy delivered in 30 fractions of 1.5 Gy. The primary endpoints were acute toxicities. The secondary endpoints included overall survival (OS), progression-free survival (PFS) and loco-regional failure-free survival (LRFFS) at 1-year of follow-up.

RESULTS: Twenty men and six women were included. The median age was 52 (30-68) months. 12 patients experienced grade 2 acute esophagitis, and 1 patient developed grade 3 acute esophagitis. Only 3 patients developed Grade 2 pneumonitis. Grade 3 or higher radiation-related pneumonia was not observed. None died of treatment-related causes. With median follow-up of 11.2 months (3.2-36.2 months), 1-year OS, PFS and LRFFS were 89.0%, 51.0% and 85.0%, respectively.

CONCLUSIONS: Dose escalation for twice-daily radiation concurrent with chemotherapy in LS-SCLC has been safely achieved up to 54 Gy for GTV using SIB-IMRT technique.