Impact of neoadjuvant therapy in downstaging of lower rectal adenocarcinoma and the role of pelvic magnetic resonance in staging

ABSTRACT Objective: to evaluate the effect of neoadjuvant therapy on the stage (TNM) of patients with rectal adenocarcinoma and validate the use of MRI as a method of determining locoregional stage. Methods: we conducted a retrospective study of 157 patients with lower rectum adenocarcinoma, whom we divided into two groups: Group 1, 81 patients (52%) who had undergone surgical treatment initially, with the purpose to analyze the accuracy of locoregional staging by pelvic magnetic resonance imaging throug the comparison of radiological findings with pathological ones; Group 2, 76 patients (48%), who had been submitted to neoadjuvant therapy (chemotherapy and radiation) prior to definitive surgical treatment, so as to evaluate its effects on the stage by comparing clinical and radiological findings with pathology. Results: In group 1, the accuracy of determining tumor depth (T) and lymph node involvement (N) was 91.4% and 82.7%, respectively. In group 2, neoadjuvant therapy decreased the T stage, N stage and TNM stage in 51.3%, 21% and 48.4% of cases, respectively. Conclusion: neoadjuvant therapy in patients with rectal adenocarcinoma is effective in decreasing disease stage, and pelvic magnetic resonance imaging is effective for locoregional staging.

摘要
研究目的：评估新辅助治疗（neoadjuvant therapy）对直肠腺癌患者TNM分期的影响，并验证磁共振成像（Magnetic Resonance Imaging，MRI）作为局部区域分期检测方法的应用价值。
方法：本研究纳入157例低位直肠腺癌患者，开展回顾性分析，将其分为两组：第1组共81例患者（占比52%），初始即接受手术治疗，通过比对盆腔磁共振成像的影像学表现与病理学结果，分析该检查用于局部区域分期的准确性；第2组共76例患者（占比48%），在接受根治性手术治疗前先接受新辅助治疗（含化疗与放疗），通过比对临床、影像学检查结果与病理学结果，评估新辅助治疗对肿瘤分期的影响。
结果：第1组中，肿瘤浸润深度（T分期）与淋巴结受累情况（N分期）的判断准确率分别为91.4%与82.7%。第2组中，新辅助治疗可分别使51.3%、21.0%与48.4%的患者的T分期、N分期与TNM分期得到降期。
结论：直肠腺癌患者接受新辅助治疗可有效降低肿瘤分期，盆腔磁共振成像在局部区域分期检测中具备良好的应用效果。