基于术前影像学和术后病理结果分析直肠癌新辅助治疗后临床完全缓解状况的临床意义

Predictive value of preoperative imaging and postoperative pathology on clinical complete response after neoadjuvant chemoradiation for locally advanced rectal cancer

目的：评价经过新辅助治疗后是否达到临床完全缓解（cCR）对进展期直肠癌患者的临床意义。方法回顾性分析北京协和医院基本外科2005—2014年间接受新辅助治疗的227例进展期直肠癌患者的临床病理资料。通过与术后病理结果进行比较，评估经术前直肠腔内超声（EUS）、磁共振成像（MRI）及术后大体病理观察原发病灶直肠黏膜的完整性3种方法判断新辅助治疗后T分期的准确性。结果术后病理结果显示，45例（19．8％，45/227）患者达到ypT0，其中40例（17．6％）达到病理完全缓解（pCR，ypT0N0），但有5例（11．1％）存在区域淋巴结转移和肠周癌结节。术前EUS、MRI及术后大体病理观察原发病灶直肠黏膜的完整性所评估的cT0预测术后ypT0的敏感度分别为19．4％（6／31）、60．0％（6／10）和17．8％（8／45），特异度分别为90．8％（89／98）、79．5％（31／39）和96．7％（176／182）。多因素Logistic回归分析结果显示，MRI术前对cT0的评估结果可独立预测ypT0（OR＝4．975，95％ CI：1．073～23．067，P＝0．040）。结论进展期直肠癌经过新辅助治疗后据cCR与否来制定治疗方案可能会导致治疗方向的错误；术前MRI对肿瘤T分期检测敏感度高于EUS和原发病灶直肠黏膜完整性与否的大体观察。

Objective To evaluate the accuracy and clinical significance of clinical complete response （cCR） after neoadjuvant themoradiotherapy for locally advanced rectal cancer. Methods Locally advanced rectal cancer patients who received neoadjuvant chemoradiotherapy following radical resection were retrospectively assessed for tumor response during 2005 to 2014 from the database of colorectal cancer. The concomitant preoperative chemoradiation consisted of 50 Gy radiation , fractionated within 5 weeks and 5-FU combined with oxaliplatin. Endorectal ultrasound and MRI were applied to preoperative staging, and postoperative gross pathologic inspection was retrospectively employed to evaluate the status of clinical complete response （cCR）. Results A total of 227 patients undergoing radical surgery were enrolled in the study. Complete pathological response （ypT0N0, pCR） was found in 40 patients （17.6%） by postoperative pathologic examination while the rate of node involved in ypT0 patients was 11.1%. The preoperative rectal MRI was more sensitive to correlate ypT0 than endorectal ultrasound and gross pathologic inspection （60.0% vs 19.4% and 17.8%）, but the accuracy and specificity showed no significant differences among these three tests. Multivariate Logistic regression analysis revealed preoperative MRI evaluation of cT0 might predict ypT0 independently （OR=4.975, 95% CI： 1.073 to 23.067, P=0.040）. Conclusion It is difficult to diagnose the primary tumor to be a cCR status based on preoperative MRI, EUS, or ulceration of rectal mucosa, and further to predict pCR. Preoperative MRI is more sensitive. The strategy of “wait and see”for cCR patients after neoadjuvant chemoradiation should be seriously considered in the decision-making before surgery.