Re-irradiation Using Intensity-modulated Radiotherapy for Recurrent and Second Primary Head and Neck Cancer

Information on re-irradiation (re-RT) for recurrent and second primary head and neck cancer is limited. Herein, a description of our long-term experience of re-RT for previously irradiated head and neck cancer is provided.

A retrospective review was performed for 73 consecutive patients re-irradiated for head and neck cancer between 2006 and 2015. Re-RT targets encompassed only the recurrent gross tumor and had tight margins (5-10 mm).

Salvage surgery was performed on 28 (38%) patients before re-RT and 53 (73%) patients received chemotherapy concurrent with re-RT. The median interval between initial and re-RT was 31 months and the median cumulative dose of the two irradiations was 126 Gy (biologically equivalent to 2 Gy fractionation). With a median survival of 33 months, locoregional recurrence after re-RT developed in 37 patients (51%; 25 infield, 12 outfield). In multivariate analysis, higher re-RT dose (≥66 Gy), longer time interval (>2 years), and use of concurrent chemotherapy were associated with improved locoregional recurrence-free survival (all p<0.05). Additionally, performance status, additional surgical resection, and longer interval were associated with better overall survival (p=0.006, 0.021, 0.004, respectively). Clinically significant acute and late toxicities occurred in 14% and 22% of evaluable patients, but no grade 5 toxicity was observed.

Moderate safety and acceptable toxicity was found after re-RT using tight margins, sufficient radiation dose, and daily image guidance. Encouraging local control and survival were obtained, similar to historical data using 1-2 cm margins.