Local Control and Toxicity of External Beam Reirradiation with Pulsed Low-Dose-Rate Technique

Publication date: Available online 23 December 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Charles T. Lee, Yanqun Dong, Tianyu Li, Samuel Freedman, Jordan Anaokar, Thomas J. Galloway, Mark A. Hallman, Stephanie E. Weiss, Shelly B. Hayes, Robert A. Price, C-M Charlie Ma, Joshua E. Meyer
PurposeTo evaluate the efficacy and toxicity of external beam reirradiation using pulsed low-dose-rate (PLDR) technique.Methods/MaterialsWe evaluated patients treated with PLDR reirradiation between 2009-2016 at a single institution. Toxicity was graded based on CTCAE4.0 and local control was assessed using RECIST1.1. In the univariate analysis (UVA), Chi-square, and Fisher's Exact test were used to assess toxicity outcomes; competing risk analysis via cumulative incidence function estimates were used to assess local progression.ResultsThirty-nine patients were treated to 41 disease sites with PLDR reirradiation, with a median follow-up of 8.8 months (range 0.5-64.7 months). Targets were thoracic, abdominal and pelvic, including 36 symptomatic sites. The median time between the first radiation course and reirradiation was 26.2 months; the median doses of the first and second courses of radiation were 50.4 Gy and 50 Gy, respectively. Five patients (13%) received concurrent systemic therapy.Out of 39 patients, 9 (23%) developed grade 2+ acute toxicity, most commonly radiation dermatitis (5/9). None developed grade 4+ acute/subacute toxicity. The only grade 2+ late toxicity was 1 patient with grade 2 late skin toxicity. In UVA, toxicity was not significantly associated with dose of the first course of radiation or reirradiation, time interval to reirradiation, or reirradiation site.Of the 41 disease sites treated with PLDR, 32 had pre and post-PLDR scans to evaluate for local control. Local progression was 16.5% at 6 months and 23.8% at 12 months, and was not associated with the dose of reirradiation, reirradiation site, or concurrent systemic therapy in UVA. Of 36 symptomatic disease sites, 25 (69%) sites achieved symptomatic response after PLDR, including 6 (17%) with complete symptomatic relief.ConclusionReirradiation with PLDR is effective and well-tolerated. Risk of late toxicity and durability of local control was limited by the relatively short follow up in this cohort.



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