Organ Preservation in Rectal Cancer: Contact X-ray Brachytherapy vs Extending the Waiting Interval and Local Excision

This trial is comparing two approaches for people with rectal cancer who respond well to radiation therapy — looking at whether the cancer can be treated without removing the rectum (called organ preservation). One approach uses a focused X-ray treatment directly on the tumor (contact X-ray brachytherapy); the other extends the waiting period after standard radiation before doing a smaller surgery to remove just the tumor. **You may be eligible if...** - You have confirmed rectal cancer (adenocarcinoma) that is within 10 cm of the anal opening - You received short-course or long-course radiation (chemoradiation) as part of your treatment plan - Your tumor shows signs of responding to radiation - You are being evaluated for possible organ-preserving treatment **You may NOT be eligible if...** - Your cancer has spread to distant organs - You are not a candidate for organ preservation based on your tumor's characteristics - You have certain health conditions that make local treatments unsafe Talk to your doctor to see if this trial is right for you.