Abstract
Introduction. In clinical settings, nodular projection (NP) and cord sign (CS) at the tumor edge and irregular nodules (IN) in the mesorectum often appeared together with extramural vascular invasion (EMVI). We aim to evaluate the diagnostic efficiency of the MRI morphology of primary tumor in predicting EMVI in patients with rectal cancer (RC). Methods. This retrospective study included 156 patients with RC. Clinical and imaging factors including NP at the primary tumor’s edge, CS at the primary tumor’s edge, maximal extramural depth (EMD), IN in the mesorectum, growth pattern, tumor length, range of rectal wall invaded (RRWI) by tumor, peritoneal reflex invasion by surgery, and pathology-proven local node involvement (PLN) were evaluated. Then, ROC curve was drawn to depict the meaningful indicators in multivariate analyses. Results. There were 53 (34%) patients with pathological extramural venous invasion (pEMVI). Among the clinical and imaging factors evaluated, NP, CS, IN, EMD, PLN, differentiation, and peritoneal reflex invasion were significantly associated with pEMVI. NP and PLN were independent predictors of EMVI. Areas under the ROC curve (AUC) of NP for prediction of EMVI was 0.82 (95% CI, 0.74–0.90), with a sensitivity of 73.58%, a specificity of 90.29%, a positive predictive value (PPV) of 75.59%, a negative predictive value (NPV) of 86.92%, and an accuracy of 84.62%, respectively. Conclusions. Patients with primary tumor with EMVI usually showed NP and CS. NP was an independent predictor of EMVI and helpful for the diagnosis of EMVI in RC patients.
Highlights
In clinical settings, nodular projection (NP) and cord sign (CS) at the tumor edge and irregular nodules (IN) in the mesorectum often appeared together with extramural vascular invasion (EMVI)
Among the 156 patients, 53 (34%) were confirmed to be pathological extramural venous invasion (pEMVI)-positive according to pathological and immune histochemistry results. e other 103 cases were Extramural venous invasion (EMVI)-negative. ere were 47 cases of proven local node involvement (PLN), 17 of which were from the EMVI-positive group and 30 of which were from the EMVI-negative group
Male Female RRWI ≤1/3 1/3–2/3 ≥2/3 NP CS IN Growth pattern Limited mass Circum wall Relation with peritoneal reflex Upper Middle Lower Peritoneal reflex invasion Negative Positive Tumor length PLN Differentiation Well Moderately Poorly EMD pEMVI: pathologic extramural vascular invasion; RRWI: range of rectal wall invaded by tumor; NP: nodular projection at the primary tumor’s edge; CS: cord sign at the primary tumor’s edge; IN: irregular nodules in the mesorectum; PLN: pathology-proven local node involvement; EMD: maximal extramural depth
Summary
Nodular projection (NP) and cord sign (CS) at the tumor edge and irregular nodules (IN) in the mesorectum often appeared together with extramural vascular invasion (EMVI). MRI, especially high-resolution T2-weighted imaging (HRT2WI), shows a very high resolution to soft tissues It can clearly display the microscopic structure around the rectum without affecting the tumors and their peripheral tissues prior to surgery. Erefore, MRI is considered as an accurate and reproducible model for the preoperative identification of EMVI (mrEMVI) as well as other local prognostic features that can be helpful to treatment plans [12–18]. Nowadays, it is used as a standard for evaluating the preoperative local staging of rectal cancer and can identify EMVI in an effective manner [19]
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