Our study evaluated whether an MRI reporting system highlighting areas of contiguous and discontinuous extramural venous invasion (EMVI) can improve the accuracy of gross tumour volume (GTV) delineation. Initially, 27 consecutive patients with locally advanced rectal cancer treated between 2012 and 2014 were evaluated. We used an MRI reporting proforma that documented the position of the primary tumour, lymph nodes and EMVI. The new GTVs delineated were compared with historical radiotherapy treatment volumes to identify the frequency of GTV geographical miss. We observed that the delineation of involved nodes and areas of EMVI was more likely to represent sources of uncertainty wherein nodal GTV geographical miss was evident in 5 out of 27 patients (19%). Complete EMVI GTV geographical miss occurred in two patients (7%). We re-evaluated our radiotherapy practice in a further 27 patients after the implementation of a modified MRI reporting system. An improvement was seen; nodal miss was observed in two patients (7%) and partial EMVI miss in one patient (4%), although these areas were encompassed in the planning target volume (PTV). Our study shows that extramural venous invasion and involved nodes need to be highlighted on MRI to improve the accuracy of rectal cancer GTV delineation.
本研究评估了通过磁共振成像（MRI）报告系统突出显示连续性与非连续性壁外静脉侵犯（EMVI）区域，能否提高大体肿瘤体积（GTV）勾画的准确性。研究首先对2012年至2014年间连续收治的27例局部进展期直肠癌患者进行评估。我们采用MRI报告模板记录原发肿瘤、淋巴结及EMVI的位置，并将新勾画的GTV与历史放疗靶区进行对比，以确定GTV地理性遗漏的发生率。结果显示，受累淋巴结及EMVI区域的勾画更易出现不确定性：27例患者中有5例（19%）出现淋巴结GTV地理性遗漏，2例（7%）发生完全性EMVI GTV地理性遗漏。随后，我们在改进MRI报告系统后对另外27例患者进行放疗实践再评估，发现勾画准确性有所提升：仅2例（7%）出现淋巴结遗漏，1例（4%）出现部分EMVI遗漏，且这些区域均被计划靶区（PTV）覆盖。研究表明，MRI报告中需重点标注壁外静脉侵犯及受累淋巴结，以提高直肠癌GTV勾画的准确性。
Radiological Biomarkers in MRI directed Rectal Cancer Radiotherapy Volume Delineation
肿瘤(癌症)患者之家