Evaluation of prognostic factors affecting re-irradiation outcomes in head and neck cancers

Re-irradiation in head neck cancers (HNCs) requires a delicate balance between adequate dose to recurrent tumor along with adequate sparing of surrounding normal tissues. Although there are several studies on re-radiation, issues pertaining to factors affecting outcomes are under evaluated. The primary aim was to evaluate survival outcomes and factors affecting it in re-irradiated HNCs treated with intensity modulated radiotherapy at our center.

Patient and disease factors affecting survival were collected and evaluated for 65 re-irradiation cases of HNCs in this study. SPSS was used for statistics.

Median follow-up was 40 months. Fifteen cases had acute grade 3 mucositis, while nine patients had acute grade 3 dysphagia. Late grade 3 toxicities were observed as follows: 2 - Osteoradionecrosis, 6 - subcutaneous fibrosis, 4 - dysphagia, 5 - xerostomia, respectively. No acute or late grade ≥4 toxicity was seen. Thirty-four cases underwent salvage surgery. The 3-year progression free survival (PFS) and overall survival (OS) were 42.5 and 54.8, respectively. 46/65 (71%) of the cases were loco-regionally recurrent (LRR). The 3-yr PFS and OS for tumors with LRR versus those second primary, were 38.3 vs 46.8% (P = 0.032), and 49.9 vs 65.9% (P = 0.075), respectively. The 3-yr PFS for stage I/II vs III/IV tumors was 49.1 vs 28.9% (P = 0.152). 2-yr PFS for multi-institution re-irradiation (MIRI) recursive partitioning analysis (RPA) Class I/II vs III was 56.8 vs 16.5%, P = 0.297. There were 28 local failures and 12 distant failures. Five patients died due non-malignant causes.

LRR cancers tend to perform poorly in terms of outcomes compared to those needing reirradiation for a second primary (SP) tumor of head neck region.