The Pattern of Failure After Reirradiation of Recurrent Squamous Cell Head and Neck Cancer: Implications for Defining the Targets

Abstract

Purpose Re-irradiation (re-RT) of recurrent head and neck cancer (HNC) may achieve long term disease control in some patients, at the expense of high rates of late sequelae. Limiting the re-RT targets to the recurrent gross tumor volume (rGTV) would reduce the volumes of re-irradiated tissues, however, its effect on tumor recurrence pattern is unknown. Methods Retrospective review of 66 patients who underwent curative-intent re-RT for non-resectable recurrent or second primary mucosal squamous cell HNC. Treatment was delivered with 3-dimensional conformal (3D) RT or intensity modulated RT (IMRT). The targets in all patients consisted of the rGTVs with tight (0.5 cm) margins, with no intent to treat prophylactically lymph nodes or sub-clinical disease in the vicinity of the rGTVs. The sites of local-regional failures (LRFs) were determined using imaging at the time of failure, and were compared to the rGTVs. Results Median re-RT dose was 68 Gy. 47 patients (71%) received concomitant chemotherapy and 31 (47%) received hyperfractionated, accelerated RT. At a median follow up 42 month, 16 (23%) are alive and free of disease. Fifty patients (77%) had a third recurrence or persistent disease, including 47 LRFs. All LRFs occurred within the rGTVs except for two (4%) (95% C.I. 0; 11 %). Nineteen patients (29%) had grade ≥3 late complications, mostly dysphagia (12 patients). Conclusion Almost all LRFs occurred within the re-irradiated rGTVs despite avoiding prophylactic RT of tissue at risk of subclinical disease. These results support confining the re-RT targets to the rGTVs to reduce re-irradiated tissue volumes.

Proton Reirradiation of Recurrent Rectal Cancer: Dosimetric Comparison, Toxicities, and Preliminary Outcomes

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Safe and Curative Brachytherapy Reirradiation with Organ-Sparing Hyaluronate Gel Injection

“…Previously irradiated tissue tends to be more hypoxic and therefore frequently more radioresistant. Popovtzer et al reported 92% of the third recurrence was the in-field of the second irradiation (reirradiation), which occurred in 77% of median 68-Gy-reirradiated patients in 154 relapsed squamous head and neck cancer patients [Popovtzer, 2009]. This suggests much higher dose may be biologically required to overcome the reparability of recurrent tumor after initial radiotherapy.…”