Salvage stereotactic re-irradiation with CyberKnife for locally recurrent head and neck cancer: a single center experience

Aims and background. We report the toxicity and preliminary clinical outcome in patients affected by locally recurrent head and neck cancer treated with stereotactic re-irradiation. Methods: Between February 2012 and August 2013, 17 patients were treated with CyberKnife as stereotactic re-irradiation for locally recurrent head and neck cancer. All patients had previously received a full dose radiation treatment with radical intent, with a median total dose of 66 Gy (range, 50-70) delivered with standard fractionation. The median interval between the primary radiotherapy and re-irradiation was 24 months (range, 10-168). Results. All patients completed the prescribed treatment, which was delivered in 5 fractions. The median tumor dose administered was 30 Gy (range, 25-35) prescribed to the 80% isodose line. Treatment sites were as follows: neck lymph nodes in 5 patients, paranasal sinuses in 5, oropharynx in 2, nasopharynx, and larynx, oral cavity, nasal fossa and parotid gland each in 1 patient. The median target volume treated was 58.7 cm(3) (range, 8.5-211.3). Sixteen patients (94%) were evaluated for response. At a median follow-up of 7.5 months (range, 2-17), 4 patients achieved complete response (25%), 5 had partial response (31%) and 7 showed stable disease (44%). No patient showed in-field progression after re-irradiation. Grade 3 acute toxicity was noted in one patient only; no late side effect was observed during the follow-up. Conclusions. Stereotactic re-irradiation with CyberKnife is an appealing non-surgical salvage treatment for selected patients with local-regionally recurrent head and neck cancer.