Balyasnikova Svetlana, Read James, Wotherspoon Andrew, Rasheed S, Tekkis Paris, Tait Diana, Cunningham David, Brown G
The Royal Marsden Hospital, NHS Foundation Trust, Sutton, Surrey, UK.
Imperial College London, London, UK.
BMJ Open Gastroenterol. 2017 Aug 14;4(1):e000151. doi: 10.1136/bmjgast-2017-000151. eCollection 2017.
Early rectal cancer (ERC) assessment should include prediction of the potential excision plane to safely remove lesions with clear deep margins and feasibility of organ preservation.
MRI accuracy for differentiating ≤T1sm2 (partially preserved submucosa) or ≤T2 (partially preserved muscularis) versus >T2 tumours was compared with the gold standard of pT stage T1sm1/2 versus ≤pT2 versus >pT2. N stage was also compared. The MRI protocol employed a standard surface phased array coil with a high resolution (0.6×0.6×3 mm resolution). The staging data were analysed from a prospectively recorded database of all ERC (≤mrT3b) treated by primary surgery.
Of 65 <mrT3b tumours, 45 were ≤pT2 and 14 were ≤pT1sm2. MRI accuracy for ≤T1sm2 was 89% (95% CI 63% to 87%), positive predictive value (PPV) 77% and negative predictive value (NPV) 92%, and for ≤T2 89% (95% CI 79% to 95%), PPV 93% and NPV 81%. Interobserver agreement between two experienced radiologists was >0.7 suggesting good agreement. 44 out of 65 patients underwent radical surgery and 22 out of 44 were ≤mrT2. MRI accuracy to predict lymph node status was 84% (95% CI 70% to 92%), PPV 71% and NPV 90%. Among the 21 out of 65 (32%) patients undergoing local excision or TEM, 20 out of 21 were staged as MR≤T2 and confirmed as such by pathology. On follow-up, none had relapse. If the decision had been made to offer local excision on MRI TN staging rather than clinical assessment, a significant increase in organ preservation surgery from 32% to 60% would have been observed (difference 23%, 95% CI 9% to 35%).
MRI is a useful tool for multidisciplinary teams (MDTs) wishing to optimise treatment options for ERC; these study findings will be validated in a prospective multicentre trial.
早期直肠癌（ERC）评估应包括预测潜在的切除平面，以安全切除具有清晰深部切缘的病变以及评估器官保留的可行性。
将磁共振成像（MRI）区分≤T1sm2（黏膜下层部分保留）或≤T2（肌层部分保留）与>T2肿瘤的准确性与pT分期T1sm1/2与≤pT2与>pT2的金标准进行比较。同时也对N分期进行了比较。MRI检查采用标准表面相控阵线圈，分辨率较高（0.6×0.6×3 mm）。分期数据来自前瞻性记录的所有接受一期手术治疗的ERC（≤mrT3b）数据库。
在65例<mrT3b肿瘤中，45例为≤pT2，14例为≤pT1sm2。MRI对≤T1sm2的准确性为89%（95%可信区间63%至87%），阳性预测值（PPV）为77%，阴性预测值（NPV）为92%；对≤T2的准确性为89%（95%可信区间79%至95%），PPV为93%，NPV为81%。两位经验丰富的放射科医生之间的观察者间一致性>0.7，表明一致性良好。65例患者中有44例接受了根治性手术，44例中有22例为≤mrT2。MRI预测淋巴结状态的准确性为84%（95%可信区间70%至92%），PPV为71%，NPV为90%。在65例（32%）接受局部切除或经肛门内镜微创手术（TEM）的患者中，21例中有20例MRI分期为≤T2，病理检查证实如此。随访期间，无一例复发。如果根据MRI的TN分期而非临床评估决定进行局部切除，器官保留手术将从32%显著增加至60%（差异23%，95%可信区间9%至35%）。
MRI是多学科团队（MDT）优化ERC治疗方案的有用工具；这些研究结果将在前瞻性多中心试验中得到验证。
