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Session:: ePosters-Mon1015-M1: Rectal Cancer

EP795 - The Significance of Detecting Extramural Venous Invasion in Rectal Cancer

Monday, May 11, 2026
10:42 AM - 10:47 AM ET

    ePoster Presenter(s)

  • Yuki Nakagawa, MD

    Graduate student
    Department of Coloproctological Surgery, Juntendo University Faculty of Medicine
    Juntendo University
    Bunkyo-ku, Tokyo, Japan

    Disclosure information not submitted.

    View ePoster

    • Author(s)

  • Saki Kochi, MD

    Graduate Student
    Department of Coloproctological Surgery, Juntendo University Faculty of Medicine
    Department of Coloproctological Surgery, Juntendo University Faculty of Medicine
    Tokyo, Tokyo, Japan

    Disclosure information not submitted.

  • Takahiro Irie, MD

    Undergraduate
    Department of Coloproctlogical Surgery, Juntendo University Faculty of Medicine
    Juntendo University
    Suginami-ku, Tokyo, Japan

    Disclosure information not submitted.

  • Kiichi Sugimoto, MD (he/him/his)

    Professor
    Department of Coloproctological Surgery, Juntendo University Faculty of Medicine, Tokyo, Japan
    Juntendo University Faculty of Medicine
    Bunkyo-ku, Tokyo, Japan

    All disclosed relationships have been reviewed and managed prior to the start of this activity. Any relevant relationships will be listed below. This individual has no relevant financial relationships.

Purpose/Background: Accurate diagnostic imaging is essential for the management of rectal cancer. Evaluation of the circumferential resection margin (CRM) and extramural venous invasion (EMVI) are representative examples. In this study, we retrospectively evaluated the clinical significance of MRI-detected EMVI (mrEMVI) in rectal cancer. Furthermore, we investigated the correlation between EMVI positivity and circulating tumor (ct) DNA methylation status.

Methods/Interventions: A total of 174 patients who underwent curative resection for locally advanced rectal cancer (pStage II/III) between 2010 and 2025 were included in this study (non-neoadjuvant therapy group: 70 cases; neoadjuvant therapy group: 104 cases). mrEMVI assessment was performed by two reviewers-a colorectal surgeon and a radiologist-using preoperative MRI images. The presence of EMVI was evaluated on T2-weighted and contrast-enhanced T1-weighted images. The mrEMVI score was classified into five grades (0-4) according to previously published criteria (Smith et al., Br J Surg. 2008), with scores 0-2 defined as mrEMVI-negative and scores 3-4 defined as mrEMVI-positive. The association between mrEMVI score and long-term prognosis (5-year recurrence-free survival: 5y-RFS) was analyzed. In addition, preoperative plasma samples from 39 patients with rectal cancer (cStage I-IV) were analyzed to investigate the correlation between mrEMVI and ctDNA methylation status of three genes-CDO1, SOX11, and CHFR-which have been reported to be associated with poor prognosis in gastroenterological cancer.

Results/Outcomes: In the non-neoadjuvant therapy group (n = 70), mrEMVI scores were as follows: score 0 in 6 patients (8.6%), score 1 in 4 (5.7%), score 2 in 44 (62.9%), score 3 in 12 (17.1%), and score 4 in 4 (5.7%). Patients were divided into a low-mrEMVI group (scores 0-2; 54 patients, 77.1%) and a high-mrEMVI group (scores 3-4; 16 patients, 22.9%). The high-mrEMVI group had a significantly worse prognosis compared with the low-mrEMVI group (5-year RFS: 48.2% vs 77.2%, p = 0.03). In the neoadjuvant therapy group (n = 104), the mrEMVI scores before treatment initiation were as follows: score 1 in 1 patient (1.0%), score 2 in 48 (46.2%), score 3 in 29 (27.9%), and score 4 in 26 (25.0%). After completion of neoadjuvant therapy, mrEMVI scores were as follows: score 0 in 7 patients (6.7%), score 1 in 11 (10.6%), score 2 in 64 (61.5%), score 3 in 18 (17.3%), and score 4 in 5 (4.8%). Among patients with low-mrEMVI scores (0-2) before treatment (49 patients, 47.1%), all remained in the low-mrEMVI category after treatment. Among those with high-mrEMVI scores (3-4) before treatment (55 patients, 52.9%), 32 patients (58.2%) converted to low-mrEMVI scores after treatment, whereas 23 (41.8%) remained high. Patients with persistently high-mrEMVI scores after treatment had significantly poorer prognosis than those with post-treatment low-mrEMVI scores (5-year RFS: 55.8% vs 71.3%, p = 0.048). Among the 39 patients whose ctDNA methylation status was analyzed, 14 were classified into the high-mrEMVI group (scores 3-4) and 25 into the low-mrEMVI group (scores 0-2).The relative methylation values (RMVs) of SOX11 and CDO1 in ctDNA methylation were significantly higher in the high-mrEMVI group than in the low-mrEMVI group (SOX11, p = 0.01; CDO1, p = 0.005).

Conclusion/Discussion: Detection of mrEMVI may be useful for predicting the prognosis of rectal cancer. The correlation between higher methylation levels of SOX11 and CDO1 in ctDNA and mrEMVI positivity suggests that mrEMVI may reflect tumor aggressiveness.

The association between mrEMVI score and long-term prognosis
In the non-neoadjuvant therapy group, the high-mrEMVI group had a significantly worse prognosis compared with the low-mrEMVI group. In the neoadjuvant therapy group, the patients with persistently high-mrEMVI scores after treatment had significantly poorer prognosis than those with post-treatment low-mrEMVI scores.
The correlation between EMVI positivity and circulating tumor DNA methylation status
The relative methylation values (RMVs) of SOX11 and CDO1 in ctDNA methylation were significantly higher in the high-mrEMVI group than in the low-mrEMVI group.