Supplementary Material for: Case Report Successful preoperative QUAD SHOT for bulky parotid carcinoma: Potential preopetative ultra-hypofractionated radiotherapy for conversion surgery

QUAD SHOT is an ultra-hypofractionated radiotherapy (RT) technique that prescribes 14.0–14.8 Gy over 2 days. Although this technique has already gained some status as an effective palliative treatment for inoperable head and neck cancer (HNC), its application in other situations has not been given much consideration. Herein, we report a case of a 62-year-old woman who received preoperative QUAD SHOT therapy for poorly differentiated parotid carcinoma. In this case, after two courses of QUAD SHOT plus a standard chemotherapy regimen with pembrolizumab, the patient’s inoperable bulky tumor shrank dramatically and became operable. Best of all, while adequate therapeutic effects were achieved, the patient’s time commitment and physical exertion were limited. RT during this period consisted of only eight fractions over four days. According to previous reports, the response rate for QUAD SHOT is sufficiently high, and the rate of serious adverse events is quite low. This case asks the question of whether the indications for QUAD SHOT irradiation can be expanded as one of the preoperative interventions undertaken by HNC surgeons to achieve conversion surgery.