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PURPOSE: Few studies have investigated the impact of the surgical proximal and distal margins on colon cancer recurrence. We conducted this study to investigate the effect of resection margins on the prognosis of resectable colon cancer. METHODS: We analyzed data on 1458 patients who underwent colorectal resection in our institute between January, 2004 and March, 2020, including 579 patients with resectable colon cancer. The association between the resection margin and recurrence for each oncological status was assessed and the value of the resection length that influenced recurrence was analyzed. RESULTS: Patients who had pT4 colon cancer with margins of more than 7 cm had a trend of fewer recurrences and longer relapse-free survival (RFS) than those with colon cancer of other stages (P = 0.033; hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.20-0.89). Multivariate analysis identified a margin of < 7 cm as an independent risk factor for RFS in patients with pT4 colon cancer (P = 0.023; HR, 2.65; 95% CI 1.013-6.17). No correlation was found between resection margins and recurrence, depending on the extent of lymph node metastasis and tumor location. CONCLUSION: A resection margin of at least 7 cm should be maintained for patients with pT4 colon cancer.
RESUMEN
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.