Preoperative Short-Course Radiation Therapy With PROtons Compared to Photons In High-Risk RECTal Cancer (PRORECT)

This study is comparing two types of radiation therapy — proton therapy and standard photon radiation — for people with high-risk rectal cancer, to see if protons can deliver the same cancer-killing effect with fewer side effects to surrounding healthy tissue. **You may be eligible if...** - You have newly diagnosed rectal cancer confirmed by biopsy - The bottom of your tumor is less than 16 cm from the anal opening - Imaging shows high-risk features such as tumor involvement near important structures, or spread to nearby lymph nodes - You are being considered for preoperative (neoadjuvant) radiation as part of your treatment **You may NOT be eligible if...** - You have had prior pelvic radiation - You have widespread metastatic disease that makes local treatment unlikely to be beneficial - You have conditions that would make surgery or radiation unsafe Talk to your doctor to see if this trial is right for you.