Prospectively Randomized Control Clinical Trial of FOLFOXIRI Preoperative Chemotherapy Alone on Rectal Cancer in Local Advance Comparing to Oral Capecitabine Combined With Long-term Radiation

This trial is comparing two treatment approaches for locally advanced rectal cancer close to or at the anus: a standard approach using long-course radiation with an oral chemotherapy pill (capecitabine) versus a newer approach using three chemotherapy drugs together (FOLFOXIRI) without radiation, to find out which works better before surgery. **You may be eligible if...** - You are between 18 and 75 years old - You have been diagnosed with rectal cancer (adenocarcinoma) confirmed by biopsy - Your tumor is in the lower rectum (close to the anal margin) and has grown through the bowel wall and/or involves lymph nodes, or is in a higher location but is still locally advanced - Your cancer has not spread to distant organs (no distant metastases) - You are considered able to have surgery to remove the cancer with clear margins (R0 resection) **You may NOT be eligible if...** - Your cancer has already spread to distant organs - You have had prior chemotherapy or radiation for rectal cancer - You have serious nerve damage or other conditions that make the drugs unsafe - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.