Reirradiation using stereotactic body radiotherapy in the management of recurrent or second primary head and neck cancer: A meta-analysis and systematic review

Objectives: We conducted a meta-analysis and systematic review of stereotactic body radiotherapy (SBRT)-based reirradiation efficacy in patients with recurrent or second primary head and neck cancer (RSHNC). Methods: We systematically reviewed PubMed/MEDLINE, Embase, and Cochrane Library. The primary endpoint was 2-year overall survival (OS); secondary endpoints were grade> 3 complications and response rate. Results: We included 10 studies involving 575 patients (only 12% of whom underwent salvage surgery post-recurrence) with RSHNC who underwent SBRT; median SBRT reirradiation doses ranged from 24 to 44 Gy (median, 30 Gy) delivered with 3-6 fractions (median, 5 fractions). Median target volume of SBRT reirradiation was measured from 19 to 103 cm(3). The pooled event rate of 2-year OS following SBRT reirradiation for RSHNC was 30.0% (95% confidence interval [CI] 24.5-36.1). The pooled rates of late grade >= 3 and grade 5 toxicity were 9.6% (95% CI 5.0-17.6) and 4.6% (95% CI 2.4-8.6), respectively. Grade 5 toxicity was not observed in five studies (range: 0-10.7%). The pooled rates of clinical response and complete response were 61.7% (95% CI 51.1-71.3) and 31.3% (95% CI 23.3-40.5), respectively, and the 2-year local control rate was 47.3% (95% CI 3.1-62.1). Conclusions: SBRT with median 30 Gy in 5 fractions is a feasible therapy showing good responses for patients with RSHNC not suitable for salvage surgery. However, to improve OS, SBRT reirradiation strategy should be investigated in terms of dose escalation for sustained control and combined systemic therapy.