Commencement of Hypofractionated Adjuvant Radiation Therapy in Intermediate-Risk Oral Cavity Cancer: A Phase 1 Study...

Oral squamous cell carcinoma (OSCC) contributes substantially to the cancer burden in India. The standard treatment involves surgical excision followed by adjuvant radiation therapy (RT) or chemo-RT, based on histopathological risk factors. Although conventionally fractionated RT remains the current standard, limited data exist on the role of hypofractionated RT (HFRT) in adjuvant setting. This trial aims to establish maximum tolerated dose and fractionation (MTDF) of adjuvant HFRT in OSCC. Secondary objectives include analyzing acute, consequential, and late toxicities associated with HFRT.

This paper describes an ongoing single-institute phase 1 trial conducted at a tertiary cancer center in India. Eligible patients with primary OSCC who have undergone radical surgery and require adjuvant RT alone will be enrolled. The study consists of 2 parts: part A (dose escalation) to determine the MTDF using a modified rolling 6 design at 3 escalating dose levels, followed by part B (dose expansion) to assess the additional toxicity profile by randomizing patients between the MTDF (n = 12) and the preceding dose level (MTDF-1) (n = 12). Randomization will be performed using a minimization technique, and stratification factors include age, primary tumor location, and nodal disease burden. The sample size for the trial is 42 (18 in part A and 24 in part B). Adjuvant HFRT doses will be optimized using a biologically effective dose model, and all treatments will be delivered with image guided RT. Predefined stopping rules will be applied for dose-limiting toxicities, which will be monitored by an independent adjunct committee.