Prognostic impact of extramural venous invasion detected by contrast-enhanced CT colonography in colon cancer

Abstract

Background: The impact of computed tomography (CT)-detected extramural venous invasion on the recurrence of colon cancer is not fully understood. The aim of this study was to investigate the clinical significance of extramural venous invasion diagnosed before surgery by contrast-enhanced CT colonography using three-dimensional multiplanar reconstruction images.

Methods: Patients with colon cancer staged greater than or equal to T2 and/or stage I-III who underwent contrast-enhanced CT colonography between 2013 and 2018 at the National Cancer Center Hospital in Japan were retrospectively investigated for CT-detected extramural venous invasion. Inter-observer agreement for the detection of CT-detected extramural venous invasion was evaluated and Kaplan-Meier survival curves were plotted for recurrence-free survival using CT-TNM staging and CT-detected extramural venous invasion. Preoperative clinical variables were analysed using Cox regression for recurrence-free survival.

Results: Out of 922 eligible patients, 544 cases were analysed (50 (9.2 per cent) were diagnosed as positive for CT-detected extramural venous invasion and 494 (90.8 per cent) were diagnosed as negative for CT-detected extramural venous invasion). The inter-observer agreement for CT-detected extramural venous invasion had a κ coefficient of 0.830. The group positive for CT-detected extramural venous invasion had a median follow-up of 62.1 months, whereas the group negative for CT-detected extramural venous invasion had a median follow-up of 60.7 months. When CT-TNM stage was stratified according to CT-detected extramural venous invasion status, CT-T3 N(-)extramural venous invasion(+) had a poor prognosis compared with CT-T3 N(-)extramural venous invasion(-) and CT-stage I (5-year recurrence-free survival of 50.6 versus 89.3 and 90.1 per cent respectively; P < 0.001). In CT-stage III, the group positive for CT-detected extramural venous invasion also had a poor prognosis compared with the group negative for CT-detected extramural venous invasion (5-year recurrence-free survival of 52.0 versus 78.5 per cent respectively; P = 0.003). Multivariable analysis revealed that recurrence was associated with CT-T4 (HR 3.10, 95 per cent c.i. 1.85 to 5.20; P < 0.001) and CT-detected extramural venous invasion (HR 3.08, 95 per cent c.i. 1.90 to 5.00; P < 0.001).

Conclusion: CT-detected extramural venous invasion was found to be an independent predictor of recurrence and could be used in combination with preoperative TNM staging to identify patients at high risk of recurrence.

Fig. 1

Flow chart showing the study inclusion and exclusion criteria

Fig. 2

Three-dimensional multiplanar reconstruction images of contrast-enhanced CT colonography at the portal venous phase for cases positive for CT-detected extramural venous invasion (a–c) and cases negative for CT-detected extramural venous invasion (d–e) a Soft-tissue opacities with a CT number (Hounsfield units) comparable to that of the tumour extending to the extramural venous lumen. An obvious irregular venous contour and venous expansion are evident (white arrows). b Soft-tissue opacities with a CT number (Hounsfield units) comparable to that of the tumour extending to the extramural venous lumen. A moderate irregular venous contour and nodular venous expansion are evident (white arrows). c Soft-tissue opacities with CT number comparable to that of the tumour extending to the extramural venous lumen. A slightly irregular venous contour and venous expansion are apparent (white arrows). d There are no veins adjacent to the tumour. e Spicula-like extensions from the tumour run towards the subserosal or retroperitoneal fat without continuity with veins (white arrowheads). F, Foot (Caudal).

Fig. 3

Kaplan–Meier survival plots for recurrence-free survival associated with CT-detected extramural venous invasion CT-EMVI, CT-detected extramural venous invasion.

Fig. 4

Kaplan–Meier survival curves for recurrence-free survival with comparison for CT-T and CT-N stage subclassified by CT-detected extramural venous invasion status a CT-stage I and CT-stage II stratified by CT-detected extramural venous invasion. b CT-stage III (CT-N positivity) stratified by CT-detected extramural venous invasion. EMVI, extramural venous invasion.