Neoadjuvant Chemotherapy in Patients With T4b or Obstructive Colon Cancer: A Single Center Retrospective Cohort Study.

BACKGROUND/AIM:The efficacy of neoadjuvant chemotherapy (NAC) for colon cancer remains unestablished. This study aimed to investigate the outcomes of NAC in patients with locally advanced T4b or obstructive T4a colon cancers (LACC). PATIENTS AND METHODS:Data of patients with LACC who underwent colon surgery between 2010 and 2022 after NAC at our institution were retrospectively reviewed. Patient characteristics, surgical outcomes, tumor features, and prognosis were analyzed. RESULTS:Among 800 patients with LACC who underwent radical resection, 11 received NAC because of cT4b or cT4a with mechanical obstruction. NAC, administered as a doublet regimen, had a median duration of three months, without grade ≥3 adverse events. R0 resection was achieved in all patients and downstaging was observed in eight patients. One patient developed a postoperative abdominal abscess, and adjuvant chemotherapy was administered to eight patients. Four patients experienced recurrence: liver metastasis in two, and local recurrence in two. Among these, three patients underwent resection of recurrent tumors. Median follow-up was 30 months. CONCLUSION:NAC is feasible for T4b or obstructive T4a colon cancer and may be a treatment option for LACC. Further large-scale studies are required to confirm the efficacy of NAC in these patients.