Prevalence of CT-detected extramural vascular invasion in gastric adenocarcinoma and its correlation with other known prognostic factors.

[PURPOSE] To study the prevalence of extramural vascular invasion (EMVI) in patients with gastric adenocarcinoma (GA) and its association with other prognostic factors.

[MATERIALS AND METHODS] In this retrospective study, consecutive patients with GA who underwent staging CT between January 2021 and December 2022 were included. Two radiologists reviewed the staging CT for EMVI and its grade and documented tumor location, thickness, and TNM stage. Grade 3 and 4 EMVI were reported as ct-EMVI positive and the rest as negative. Similar findings were documented on restaging CT following neoadjuvant chemotherapy (NAC) when available. ct-EMVI was compared with imaging findings on staging and restaging CT, staging laparoscopy findings, peritoneal fluid cytology, and surgical histopathology findings.

[RESULTS] A total of 191 patients (140 males, 51 females) with a mean age of 53 ± 9 years (range 23-93 years) were included. 82.2% had poorly differentiated GA and 17.8% had well/moderately differentiated GA. The majority (95.9%) had T3 (n = 34) and T4 (n = 118) disease on baseline CT. The prevalence of ct-EMVI on staging CT was 65% (n = 124), and 34% and 86% among the T3 and T4 GA, respectively. There was a significant association between ct-EMVI and, tumor thickness, tumor extent, ct-T, N, M stages, and especially peritoneal, lymph nodes, and liver metastases and response to NAC (p < 0.05).

[CONCLUSION] EMVI is seen commonly in staging CT of advanced gastric cancer patients and is significantly associated with TNM stage, peritoneal metastases, and response to neoadjuvant chemotherapy. Thus, ct-EMVI is a significant prognostic imaging biomarker in GA. IRB min no: 15713.