Patterns of Failure for Recurrent Head and Neck Squamous Cell Carcinoma Treated with Salvage Surgery and Postoperative IMRT Reirradiation

Purpose/ObjectivesDetermining the optimal postoperative reirradiation volume following salvage surgery for recurrent head and neck squamous cell cancer (HNSCC) is critical given the significant risk of severe reirradiation toxicity and need to provide durable local control. The purpose of this study was to evaluate patterns of locoregional recurrence (LRR) after surgical salvage and adjuvant reirradiation with IMRT.Materials/MethodsPatterns of LRR for 61 patients treated consecutively between 2003-2014 who received post-operative IMRT reirradiation to ≥60 Gy for recurrent HNSCC were determined by 2 methods: 1) physician classification via visual comparison of post-radiotherapy imaging to reirradiation plans; and 2) using deformable image registration (DIR). Those without evaluable CT planning image data were excluded. All recurrences were verified by biopsy or radiological progression. Failures were defined as in-field, marginal, or out-of-field. Logistic regression analyses were performed to identify predictors for LRR.ResultsA total of 55 patients were eligible for analysis and 23 (42%) had documented LRR after reirradiation. Location of recurrent disease prior to salvage surgery (lymphatic vs. mucosal) was the only significant predictor of LRR after post-operative reirradiation (p = 0.037). Physician classification of LRR yielded 14 (61%) in-field failures, 3 (13%) marginal failures, and 6 (26%) out-of-field failures, while DIR yielded 10 (44%) in-field failures, 4 (17%) marginal failures, and 9 (39%) out-of-field failures. Most failures (57%) occurred within the original site of recurrence or first echelon lymphatic drainage. Of patients who had a free flap placed during salvage surgery, 56% of failures occurred within 1 cm of the surgical flap.ConclusionThe majority of locoregional recurrences after surgical salvage and adjuvant reirradiation for recurrent HNSCC occurred marginally or in-field, often in or near the anastomotic site.