Three-Dimensional Radiation Therapy to the Primary Tumor With Concurrent Chemotherapy in Patients With Stage IV Non-Small Cell Lung Cancer: Results of a Multicenter Phase 2 Study From PPRA-RTOG, China

Abstract

The aim of this prospective multi-institutional phase 2 study was to investigate disease control, survival outcomes, and toxicity after thoracic three-dimensional radiation therapy (3D-RT) with concurrent chemotherapy for newly diagnosed stage IV non-small cell lung cancer (NSCLC). Eligible patients were 18 to 80 years of age, had a Karnofsky performance status (KPS) score ≥70%, and newly diagnosed stage IV NSCLC with limited metastatic disease (defined as involving ≤3 organs). Patients received platinum-doublet chemotherapy with concurrent irradiation to the primary tumor. Primary endpoints were overall survival (OS) and acute toxicity. From May 2008 to May 2012, 198 eligible patients were enrolled from 7 cancer centers. Most patients died with distant metastasis; only 10% died with isolated primary recurrence. Median OS time was 13.0 months (95% confidence interval [CI]: 11.7-14.3); OS rates were 53.5% at 1 year, 15.8% at 2 years, and 9.2% at 3 years. Median progression-free survival (PFS) time was 9.0 months (95% CI: 7.7-10.3); corresponding PFS rates were 30.8%, 8.2%, and 6.1%. The 1-year, 2-year, and 3-year local (primary tumor) control rates were 78.8%, 57.7%, and 55.4%. Multivariate analysis showed that delivery of ≥63 Gy to the primary tumor (P=.014), having a primary tumor volume <134 cm(3) (P=.008), and having a stable or higher KPS score after treatment (P=.01) were independent predictors of better OS. The most common severe (grades 3-4) acute toxicities were hematologic: leukopenia (37.9%), thrombocytopenia (10.1%), and anemia (6.9%). No patients experienced grade 4 or 5 radiation-related toxicity; 2.5% had acute grade 3 pneumonitis, and 6.6% had acute grade 3 radiation esophagitis. Thoracic 3D-RT to the primary tumor with concurrent chemotherapy led to satisfactory survival outcomes with acceptable toxicity. Radiation dose, primary tumor volume, and PFS after treatment all predicted survival in these patients with limited-metastasis NSCLC.