Multicenter phase 2 trial of postoperative SBRT efficacy and late toxic effects in early-stage oropharyngeal and oral cavity cancers

Postoperative radiotherapy, mainly fractionated intensity-modulated radiotherapy, is indicated after surgery for early-stage oral cavity squmaous cell carcinoma (OCSCC) and oropharyngeal squamous cell carcinome (OPSCC) in the presence of high-risk margins. Postoperative brachytherapy may be an option but is not always feasible. Stereotactic body radiotherapy (SBRT) may offer a noninvasive alternative. The phase 2 STEREOPOSTOP-GORTEC 2017-03 trial, at 18 centers in France, evaluated postoperative SBRT to the primary tumor bed among patients with early-stage OCSCC or OPSCC and high-risk resection margins. In this nonrandomized clinical trial including 90 patients, the incidence of severe late toxic effects at 2 years was 2.2% and the 2-year local control rate was 92.0%. The trial met both predefined efficacy and safety targets. The authors conclude that postoperative SBRT to the primary tumor bed appeared to be a safe and effective treatment option in this specific population.