Objective: To explore the predictive factors of pathological complete response (pCR) after neoadjuvant chemoradiotherapy for middle-low rectal cancer. Methods: A case-control study was conducted. The inclusion criteria were as follows: (1) colonoscopy, digital examination or magnetic resonance imaging (MRI) showed a distance from the lower edge of the tumor to the dentate line of no more than 10 cm; (2) complete clinicopathological data were available; (3) preoperative biopsy revealed adenocarcinoma; (4) preoperative pelvic MRI or endorectal ultrasonography was performed; (5) no distant metastasis was found. Exclusion criteria: (1) preoperative radiotherapy and chemotherapy were not administrated according to the standard; (2) simultaneous multiple primary cancer and familial adenomatous polyposis were observed. According to the above criteria, clinicopathological data of 245 patients with middle-low rectal cancer undergoing preoperative neoadjuvant chemoradiotherapy in Changhai Hospital of Navy Medical University from January 2012 to December 2019 were retrospectively collected. Univariate analysis and multivariate logistic analysis were used to identify the clinical factors predicting pCR. pCR is defined as complete disappearance of cancer cells under the microscope in cancer specimens (including lymph nodes) after neoadjuvant chemoradiotherapy. Results: A total of 72 patients with pCR were enrolled in this study. Univariate analysis showed that preoperative T stage, tumor circumference, tumor morphology, carbohydrate antigen (CA) 19-9, interval between the end of neoadjuvant therapy and operation were associated with pCR (all P<0.05). The above 5 variables were included in multivariate logistic analysis and the results revealed that the T stage (OR=5.743, 95% CI: 2.416-13.648, P<0.001), tumor circumference (OR=7.754, 95% CI: 3.822-15.733, P<0.001), tumor morphology (OR=0.264, 95% CI: 0.089-0.786, P=0.017) and the interval between the end of neoadjuvant therapy and operation (OR=0.303, 95% CI: 0.147-0.625, P=0.001) were independent predictive factors of pCR, while CA 19-9 level was not an independent factor (OR=1.873, 95% CI:0.372-9.436, P=0.447). Conclusion: By knowing the clinical features of preoperative T stage, tumor circumference, tumor morphology and the interval between neoadjuvant chemoradiotherapy and operation, patients with higher likelyhood of pCR after neoadjuvant chemoradiotherapy may be identified.
目的： 探讨影响中低位直肠癌新辅助放化疗后病理完全缓解（pCR）的影响因素。 方法： 采用病例对照研究的方法。病例纳入标准：（1）结肠镜或指检或磁共振（MRI）检查提示肿瘤下缘距离齿状线10 cm以内；（2）有完整的临床病理资料；（3）术前活检结果为直肠腺癌；（4）术前行盆腔MRI或直肠腔内超声检查；（5）未发现有远处转移。病例排除标准：（1）术前放化疗未按标准执行；（2）同时性多原发癌及家族性腺瘤性息肉病患者。根据上述标准，回顾性收集2012年1月至2019年12月期间，海军军医大学附属长海医院收治的245例接受术前新辅助放化疗的中低位直肠癌临床病理资料。采用单因素分析及logistic多因素分析影响新辅助治疗术后pCR的临床因素。pCR定义为直肠癌新辅助放化疗后手术切除的肿瘤标本（包括淋巴结）中显微镜下肿瘤细胞完全消失。 结果： 本研究入组72例pCR患者。单因素分析显示，pCR与患者肿瘤术前T分期、肿瘤周径、肿瘤形状、糖类抗原19-9、放化疗结束与手术的间隔时间有关（均P<0.05）。将以上变量纳入多因素logistic回归分析，结果显示：术前T分期（OR=5.743，95% CI：2.416~13.648，P<0.001）、肿瘤周径（OR=7.754，95% CI：3.822~15.733，P<0.001）、肿瘤形状（OR=0.264，95% CI：0.089~0.786，P=0.017）以及新辅助治疗结束与手术间隔（OR=0.303，95% CI：0.147~0.625，P=0.001）是影响本组新辅助治疗直肠癌患者术后发生pCR的独立因素；而糖类抗原19-9水平并不是其独立影响因素（OR=1.873，95% CI：0.372~9.436，P=0.447）。 结论： 通过对中低位直肠癌患者术前临床T分期、肿瘤周径、肿瘤形状和新辅助放化疗后与手术间隔时间等临床特征的判断，可甄别新辅助治疗后可能出现pCR的患者。.
Keywords: Neoadjuvant chemoradiotherapy; Pathological complete response; Rectal neoplasms.