Based on the above considerations, our team maintains that it is currently imperative to conduct a prospective multicenter registry study. This study would involve sectioning and submitting fresh surgical specimens from the ileum mesentery of patients undergoing radical resection for cecal cancer and proximal ascending colon cancer (right-sided colon cancer). The objectives are to: Clarify the distribution range of metastatic lymph nodes within the ileum mesentery; Conduct survival follow-up on enrolled patients; Provide reliable evidence-based medical evidence for the individualized determination of ileal resection margins.

Inclusion Criteria:

Age 18-80 years; ECOG performance status 0-2; Histologically confirmed colon adenocarcinoma; Surgical specimen confirming tumor location at: ileocecal valve orifice (cecal cancer), OR proximal ascending colon cancer with tumor ≤5 cm from ileocecal valve; Clinical stage: cT2-4aN0M0, OR cTanyN+M0; Patient and family members fully understand the study and voluntarily participate by signing informed consent

Exclusion Criteria:

Synchronous or metachronous multiple primary colon cancers (Note: Synchronous: diagnosed within 6 months; Metachronous: diagnosed >6 months apart); Preoperative neoadjuvant therapy (chemotherapy, immunotherapy, or radiotherapy) that may cause tumor regression or downstaging; Patients undergoing salvage radical surgery after endoscopic resection.

Patient with cecal cancer and proximal ascending colon cancer