Radical Accelerated Hypofractionated Three-Dimensional Conformal Radiation Therapy (AHRT) for NSCLC

Abstract

Increasing the radiation therapy dose can result in improved local control for non-small cell lung cancer (NSCLC) and can thereby improve survival. This can be compromised by accelerated repopulation of tumor cells during radiation therapy. Accelerated hypofractionated radiation therapy (AHRT) can expose tumors to a high-dose of radiation in a short period of time. We have employed this approach in two groups of NSCLC: 1) early-stage NSCLC patients who cannot tolerate the SABR treatment process (for example, extended periods in the treatment position) or who cannot travel to a center with SABR and 2) stage III NSCLC unfit for concurrent chemotherapy. This study was performed to evaluate the feasibility of utilizing AHRT for these patients. Seventy-three patients (44 stage I–II and 29 local advanced NSCLC) were included. All patients had FDG-PET scan. Only the primary tumor and the positive mediastinal areas on the pretreatment FDG-PET scan were irradiated. Mean age was 78.2 ± 7.9 years. The performance status (PS) was >2 in 49% of cases. The radiation therapy was delivered in 2.75 Gy fractions, once daily to a total dose of 66 Gy (BED10: 84 Gy). Sequential chemotherapy (mainly platinum and vinorelbine) was administered in 95% of stage III patients. Acute/late toxicity was evaluated using the RTOG criteria After a mean follow-up of 2 years, the median overall survival (OS) and cause specific survival (CSS) were 23 and 54 months, respectively. Table shows OS and CSS rates according to the stage. On multivariate Cox regression analysis, PS >2 was an independent risk factor for OS (P < .0001) and CSS (P < .0001). The major acute adverse reactions were grade 2 dermatitis (18%), grade 2 esophagitis (10%) and grade 1 pneumonitis (30%). There were 32 patients with grade 1 late pneumonitis.Oral Scientific Abstracts 200; Table 1STAGE1 year(%)2 years(%)3 years(%)median(months)IOS77595143CSS969078------IIOS58392613CSS81654328IIIOS61392415CSS64443921 Open table in a new tab Accelerated hypofractionated RT is a reasonable alternative to conventional fractionated radiotherapy in stage I–II NSCLC without access to SABR and in stage III patients unfit for concurrent chemotherapy. In both groups, treatment was well tolerated without grade 3 or higher treatment-related toxicity. PS >2 was an independent risk factor for OS and CSS.