Extramural venous invasion (EMVI) in colorectal cancer is associated with increased cancer recurrence and cancer-related death.

INTRODUCTION: Colorectal cancer (CRC) outcomes vary depending on tumour biology, with several features used to predict disease behaviour. Extramural venous invasion (EMVI) is associated with negative outcomes and its presence has been established as an indicator of more aggressive disease in CRC. METHODS: A prospectively maintained database was examined for patients undergoing curative resection for non-metastatic CRC between 2012 and 2018 in a tertiary institution. Clinicopathological factors were compared to assess their impact on recurrence, all-cause mortality and cancer-related death. Kaplan Meier analysis of the association between EMVI and these endpoints was performed, and univariable and multivariable analysis was carried out to establish the relationship of predictive factors in oncological outcomes. RESULTS: Eighty-eight (13.5%) of 654 patients developed recurrence. The mean time to recurrence was 19.8 ± 13.5 months. There were 36 (5.5%) cancer-related deaths at a mean duration of follow-up of 46.3 ± 21.6 months. Two hundred and sixty-six patients had extramural venous invasion (40.7%). EMVI was significantly associated with reduced overall recurrence-free survival, systemic recurrence-free survival, and increased cancer-related death on univariate analysis (p < 0.001 for all, Fig. 1), and multivariable analysis (OR 1.8 and 2.1 respectively, p < 0.05 for both). CONCLUSION: EMVI is associated with a poor prognosis, independent of stage, nodal status and other histopathological features. The presence of EMVI should be strongly considered as an indication for adjuvant therapy.

Clinical correlation and molecular evaluation confirm that the MLH1 p.Arg182Gly (c.544A>G) mutation is pathogenic and causes Lynch syndrome.

Approximately 25 % of mismatch repair (MMR) variants are exonic nucleotide substitutions. Some result in the substitution of one amino acid for another in the protein sequence, so-called missense variants, while others are silent. The interpretation of the effect of missense and silent variants as deleterious or neutral is challenging. Pre-symptomatic testing for clinical use is not recommended for relatives of individuals with variants classified as 'of uncertain significance'. These relatives, including non-carriers, are considered at high-risk as long as the contribution of the variant to disease causation cannot be determined. This results in continuing anxiety, and the application of potentially unnecessary screening and prophylactic interventions. We encountered a large Irish Lynch syndrome kindred that carries the c.544A>G (p.Arg182Gly) alteration in the MLH1 gene and we undertook to study the variant. The clinical significance of the variant remains unresolved in the literature. Data are presented on cancer incidence within five kindreds with the same germline missense variant in the MLH1 MMR gene. Extensive testing of relevant family members in one kindred, a review of the literature, review of online MMR mutation databases and use of in silico phenotype prediction tools were undertaken to study the significance of this variant. Clinical, histological, immunohistochemical and molecular evidence from these families and other independent clinical and scientific evidence indicates that the MLH1 p.Arg182Gly (c.544A>G) change causes Lynch syndrome and supports reclassification of the variant as pathogenic.