Ozawa Heita, Kotake Kenjiro, Ike Hideyuki, Sugihara Kenichi
Department of Surgery, Tochigi Cancer Center, Utsunomiya, Japan.
Department of Gastroenterological Surgery, Sano City Hospital, Sano, Japan.
J Anus Rectum Colon. 2020 Apr 28;4(2):59-66. doi: 10.23922/jarc.2019-013. eCollection 2020.
The necessary and sufficient length of the distal resection margin (l-DRM) for rectosigmoid cancer remains controversial. This study evaluated the validity of the 3-cm l-DRM rule for rectosigmoid cancer in the Japanese classification of colorectal cancer.
We retrospectively reviewed 1,443 patients with cT3 and cT4 rectosigmoid cancer who underwent R0 resection in Japanese institutions between 1995 and 2004. We identified the optimal cutoff point of the l-DRM affecting overall survival (OS) rate using a multivariate Cox regression analysis model. Using this cutoff point, the patients were divided into two groups after balancing the potential confounding factors of the l-DRM using propensity score matching, and the OS rates of the two groups were compared.
A multivariate Cox regression analysis model revealed that the l-DRM of 4 cm was the best cutoff point with the greatest impact on OS rate (hazard ratio [HR], 1.37; 95% confidence interval [CI], 1.00-1.84; P = 0.0452) and with the lowest Akaike information criterion value. In the matched cohort study, the OS rate of patients who had l-DRM of 4 cm or more was significantly higher than that of patients who had l-DRM < 4 cm (n = 402; 5-year OS rates, 87.6% vs. 80.3%, respectively; HR, 1.60; 95% CI, 1.09-2.31; P = 0.0136).
For cT3 and cT4 rectosigmoid cancer, l-DRM of 4 cm may be an appropriate landmark for a curative intent surgery, and we were unable to definitively confirm the validity of the Japanese 3-cm l-DRM rule.
乙状结肠癌远端切缘（l-DRM）的必要且足够长度仍存在争议。本研究评估了日本结直肠癌分类中乙状结肠癌3 cm l-DRM规则的有效性。
我们回顾性分析了1995年至2004年在日本机构接受R0切除的1443例cT3和cT4乙状结肠癌患者。我们使用多变量Cox回归分析模型确定影响总生存率（OS）的l-DRM最佳截断点。利用该截断点，通过倾向评分匹配平衡l-DRM的潜在混杂因素后将患者分为两组，并比较两组的OS率。
多变量Cox回归分析模型显示，4 cm的l-DRM是对OS率影响最大的最佳截断点（风险比[HR]，1.37；95%置信区间[CI]，1.00-1.84；P = 0.0452），且赤池信息准则值最低。在匹配队列研究中，l-DRM为4 cm或更长的患者的OS率显著高于l-DRM < 4 cm的患者（n = 402；5年OS率分别为87.6%和80.3%；HR，1.60；95% CI，1.09-2.31；P = 0.0136）。
对于cT3和cT4乙状结肠癌，4 cm的l-DRM可能是根治性手术的合适标志，且我们无法明确证实日本3 cm l-DRM规则的有效性。
