Various tumor characteristics might lead to inaccurate local MRI-defined stage of rectal cancer and the purpose of this study was to explore the clinicopathological factors that impact on the precision pre-treatment MRI-defined stage of rectal cancer. A retrospectively analysis was conducted in non-metastatic rectal cancer patients who received radical tumor resection without neoadjuvant treatment during 2007–2015 in the Sixth Affiliated Hospital of Sun Yat-sen University. Clinical T stage and N stage defined by pelvic enhanced MRI and pathological stage were compared and patients were subdivided into accurate-staging, over-staging and under-staging subgroups. Logistic regressions were used to explore risk factors for over-staging or under-staging. Five hundred fifty-one cases of patients were collected. Among them, 109 cases (19.4%) of patients were over-T-staged and 50 cases (8.9%) were under-T-staged, while 78 cases (13.9%) were over-N-staged and 75 cases (13.3%) were under-N-staged. Logistic regression suggested that pre-operative bowel obstruction was risk factor for over-T-staging (OR = 3.120, 95%CI: 1.662–5.857, P < 0.001) as well as over-N-staging (OR = 3.494, 95%CI: 1.797–6.794, P < 0.001), while mucinous adenocarcinoma was a risk factor for under-N-staging (OR = 4.049, 95%CI: 1.876–8.772, P < 0.001). Patients with larger tumor size were at lower risk for over-T-staging (OR = 0.837, 95%CI: 0.717–0.976, P = 0.024) and higher risk for over-N-staging (OR = 1.434, 95%CI: 1.223–1.680, P < 0.001). Bowel obstruction, mucinous adenocarcinoma and tumor size might have impact on the pre-operative MRI T staging or N staging of rectal cancer. Our results reminded clinicians to assess clinical stage individually in such rectal cancer patients.

中文翻译：

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直肠癌术前MRI分期不正确的危险因素分析

各种肿瘤特征可能导致直肠癌的MRI定义的局部分期不准确，本研究的目的是探讨影响直肠癌MRI精确定义的精确治疗前期的临床病理因素。中山大学附属第六医院于2007-2015年对未经新辅助治疗而接受根治性肿瘤切除的非转移性直肠癌患者进行了回顾性分析。比较骨盆增强MRI和病理分期定义的临床T期和N期，并将患者分为准确分期，过度分期和分期不足的亚组。Logistic回归用于探讨过度分期或分期不足的风险因素。收集了551例患者。其中109例（19。超过T分期的患者为4％，低于T分期的患者为50例（8.9％），超过N分期的患者为78例（13.9％），低于N分期的患者为75例（13.3％）上演。Logistic回归表明，术前肠梗阻是过度T分期（OR = 3.120，95％CI：1.662–5.857，P <0.001）以及过度N分期（OR = 3.494，95％）的危险因素。 CI：1.797–6.794，P <0.001），而黏液腺癌是N分期不足的危险因素（OR = 4.049，95％CI：1.876–8.772，P <0.001）。肿瘤较大的患者发生过度T分期的风险较低（OR = 0.837，95％CI：0.717–0.976，P = 0.024），而发生过度N分期的风险较高（OR = 1.434，95％CI： 1.223–1.680，P <0.001）。肠梗阻，粘液性腺癌和肿瘤大小可能会影响直肠癌的术前MRI T分期或N分期。