van den Broek Joris J, van der Wolf Floor S W, Lahaye Max J, Heijnen Luc A, Meischl Christof, Heitbrink Martin A, Schreurs W Hermien
1 Department of Surgery, Medical Centre Alkmaar, Alkmaar, the Netherlands 2 Department of Radiology, Medical Centre Alkmaar, Alkmaar, the Netherlands 3 Department of Radiology, Maastricht University Medical Centre, Maastricht, the Netherlands 4 Department of Pathology, Medical Centre Alkmaar, Alkmaar, the Netherlands.
Dis Colon Rectum. 2017 Mar;60(3):274-283. doi: 10.1097/DCR.0000000000000743.
Patients with a locally advanced rectal carcinoma benefit from preoperative chemoradiotherapy. MRI is considered the first choice imaging modality after preoperative chemoradiation, although its reliability for restaging is debatable.
The purpose of this study was to determine the accuracy of MRI in restaging locally advanced rectal cancer after preoperative chemoradiation.
This was a retrospective study.
The study was conducted in a Dutch high-volume rectal cancer center.
A consecutive cohort of 48 patients with locally advanced rectal cancer treated with a curative intent was identified.
Three readers independently evaluated the MRI both for primary staging and for restaging after preoperative chemoradiation and were blinded to results from the other readers as well as histological results. Interobserver variability was determined. Accuracy of the restaging MRI was assessed through the comparison of tumor characteristics on MRI with histopathologic outcomes.
T stage was correctly predicted by the 3 readers in 47% to 68% and N stage in 68% to 70%. Overstaging was more common than understaging. Positive predictive values (PPV) among the 3 readers for T0 were 0%, and negative predictive values (NPVs) varied from 84% to 85%. For T1/2, PPVs and NPVs were 50% to 67% and 72% to 90%, and for T3/4 they were 54% to 62% and 33% to 78%. PPVs and NPVs for N0 stage were 81% to 95% and 58% to 73%. Tumor regression grade on MRI did not correspond with histopathologic tumor regression grade; PPVs for good response (tumor regression grade on MRI 1-2) were 48% to 61%, and NPVs were 42% to 58%. Interobserver agreement was fair to moderate for T stage, N stage, and tumor response (κ = 0.20-0.41) and fair to substantial for the relation with the mesorectal fascia (κ = 0.33-0.77). In none of the patients was the surgical plan changed after the restaging MRI.
This study was limited by its small sample size and retrospective nature.
MRI has low accuracy for restaging locally advanced rectal cancer after preoperative chemoradiation, and the interobserver variability is significant.
局部晚期直肠癌患者可从术前放化疗中获益。MRI被认为是术前放化疗后首选的成像方式，尽管其再分期的可靠性存在争议。
本研究旨在确定MRI对局部晚期直肠癌术前放化疗后再分期的准确性。
这是一项回顾性研究。
该研究在荷兰一家大型直肠癌中心进行。
连续纳入48例接受根治性治疗的局部晚期直肠癌患者。
三位阅片者独立评估MRI用于术前放化疗前的初始分期和放化疗后的再分期，且对其他阅片者的结果以及组织学结果不知情。确定观察者间的变异性。通过比较MRI上的肿瘤特征与组织病理学结果来评估再分期MRI的准确性。
三位阅片者对T分期的正确预测率为47%至68%，对N分期的正确预测率为68%至70%。分期过高比分期过低更常见。三位阅片者对T0的阳性预测值（PPV）为0%，阴性预测值（NPV）在84%至85%之间。对于T1/2，PPV和NPV分别为50%至67%和72%至90%，对于T3/4，PPV和NPV分别为54%至62%和33%至78%。N0期的PPV和NPV分别为81%至95%和58%至73%。MRI上的肿瘤退缩分级与组织病理学肿瘤退缩分级不相符；良好反应（MRI上肿瘤退缩分级为1 - 2级）的PPV为48%至61%，NPV为42%至58%。观察者间对T分期、N分期和肿瘤反应的一致性为中等至良好（κ = 0.20 - 0.41）；对与直肠系膜筋膜关系方面的一致性为中等至显著（κ = 0.33 - 0.77）。再分期MRI后，没有一位患者更改手术方案。
本研究受样本量小和回顾性研究性质所限。
MRI对局部晚期直肠癌术前放化疗后的再分期准确性较低，且观察者间变异性显著。
