Shortening Radiation Course Duration Using Simultaneous Integrated Boost With Lower Intensity Elective Nodal Dosing and Concurrent Chemotherapy for High-Risk Anal Squamous Cell Carcinoma

This phase 2 single-arm study will evaluate whether a shortened course of mildly hypofractionated radiation therapy given with standard concurrent chemotherapy (mitomycin C and capecitabine) can provide acceptable tumor control in patients with high-risk non-metastatic anal squamous cell carcinoma. Standard chemoradiation for anal cancer typically requires approximately 5.5 to 6 weeks of daily radiation, which can create substantial logistical burden for patients and caregivers, particularly those in rural settings. The investigational approach uses a 23-fraction radiation regimen designed to shorten treatment duration while maintaining biologically equivalent tumor-directed dosing compared with standard treatment. The primary question is whether this shorter chemoradiation regimen can achieve an acceptable 6-month complete clinical response rate while maintaining manageable toxicity.