The Outcome of Reirradiation With Curative Intent: Analysis of 247 Patients in 6 Years

Abstract

In recent decades, the number of long-term cancer survivors has increased. This has caused increasing requests for the delivery of a second course of radiation to recurrent tumors that occurred in previous radiation therapy fields. Most radiation oncologists are reluctant to offer reirradiation due to a lack of experience and potential toxicity. We reviewed our experience during 6 years and analyzed the outcome, in terms of tumor response, survival rates, and toxicity. A total of 247 patients reirradiated with IMRT between 01/2008 and 06/2014 at Miyakojima iGRT Clinic were analyzed. The prescribed doses were corrected to the biologically effective dose (BED) using the linear-quadratic (LQ) formulation for intercomparison over a wide variety of fraction sizes. The median BED10 of the first radiation therapy was 60Gy (12-134Gy). The median interval between the first and second radiation therapy courses was 18 months (1-308 months). The median BED10 of reirradiation was 77Gy (20-107Gy). The median follow-up after reirradiation was 9 months (1–66 months). All patients completed the prescribed course of reirradiation and acute toxicity was limited. A total of 23 (9.3%) patients developed grade>3 late toxicity with the reirradiated sites including head and neck, chest, and abdomen/pelvis in 56.5%, 21.7%, and 21.7% of patients, respectively. Local recurrence was observed in 31 patients (12.6%). Median overall survival and 2-year overall survival rate after reirradiation were 18.5 months and 45.0% (95% CI, 37.1-52.5%). The low toxicity of reirradiation by using modern techniques should allow the delivery of higher doses and, as a consequence, lead to an improvement in the reirradiation outcome.