Study on the No.253 Lymph Node Metastasis Patterns in Left-Sided Colon and Rectal Cancer

This observational study examines patterns of lymph node spread to a specific area (the No. 253 node, which sits near a major abdominal artery) in patients undergoing surgery for left-sided colon or rectal cancer. Understanding this spread pattern may help surgeons decide whether these nodes need to be routinely removed during cancer surgery. **You may be eligible if...** - You are 18 to 75 years old - You underwent laparoscopic colon or rectal cancer surgery (left hemicolectomy, sigmoid colectomy, or rectal resection) - Your post-surgical pathology confirmed adenocarcinoma - There is no evidence of distant spread (metastasis) **You may NOT be eligible if...** - You have had a previous colorectal cancer - You have had multiple prior abdominal surgeries - Your surgery was done as an emergency (due to obstruction, perforation, or bleeding) - The surgery did not achieve full removal of the cancer (R0 resection) - You have multiple primary colorectal cancers or another concurrent cancer Talk to your doctor to see if this trial is right for you.