Extramural venous invasion as a factor of distant metastasis in patients with locally advanced rectal cancer

Aim: In this article extramural venous invasion (EMVI) in patients with locally advanced rectal cancer (LARC) is evaluated as a risk factor of distant metastasis. Materials and methods: This study is based on experience made in proctological department of N.N. Blokhin National Medical Research Center of Oncology. Retrospective analysis was performed on a group of 230 patients with LARC with stage mrT3(CRM+)/T4N0-2M0. All patients underwent long course of chemoradiotherapy with capecetabine, then 2-4 courses of chemotherapy CapOx were conducted in induction and/or consolidation scheme. Results: There were no critical differences in the effect of EMVI (+) on the development of reccurences in comparison with the EMVI (-) group (p>0.05). Along with that EMVI(+) patients were significantly associated with distant metastasis (43 patients - 27,4%) then in EMVI(-) group (2 - 2,74%) (p<0,05). The positive mr-EMVI result was more likely to be present in patients with T4 then in T3 group (p<0,05). A positive EMVI status was 81,4% in patients with the III stage, which is significant higher than in patients with II stage - 55,7% (p<0,05). 3-year recurrent-free survival of patients with EMVI(+) was 64%, compared with the group of patients with EMVI (-) - 93%, which was a significant difference (HR 0.03; 95% CI, 0.08-0.19 p<0.001). Conclusion: The definition of extramural vascular invasion indicates a poor prognosis and could be used for treatment planning of neoadjuvant chemoradiation and adjuvant chemotherapy.