Radical external beam re‐irradiation in the treatment of recurrent head and neck cancer: Critical review

Abstract Management of patients with recurrent head and neck cancer remains a challenge for the surgeon as well as the treating radiation oncologist. Even in the era of modern radiotherapy, the rate of severe toxicity remains high with unsatisfactory treatment results. Intensity‐modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT), and heavy‐ion irradiation have all emerged as highly conformal and precise techniques that offer many radiobiological advantages in various clinical situations. Although re‐irradiation is now widespread in clinical practice, little is known about the differences in treatment response and toxicity using diverse re‐irradiation techniques. In this review, we provide a comprehensive overview of the role of radiation therapy in recurrent or second primary head and neck cancer including patient selection, therapeutic outcome, and risk using different re‐irradiation techniques. Critical review of published evidence on IMRT, SBRT, and heavy‐ion full‐dose re‐irradiation is presented including data on locoregional control, overall survival, and toxicity.