Is the non-metastatic, locally advanced colon adenocarinoma a distinct biological tumor variant? A study based on pathological evaluation, immunohistochemical panel and survival.

Objective: to evaluate the clinical and pathological differences between locally advanced colonic adenocarcinomas (LACA) with adhesions between adjacent organs or structures, and colonic adenocarcinomas with other clinical presentations.

Methods: we conducted a retrospective study from a convenience sample of patients with colonic adenocarcinoma, pathological stage pT3, distributed according to clinical and pathological characteristics in three groups: locally advanced tumors (LACA), pT3 tumors without adhesions or distant metastases (SF) and tumors with metastatic disease (M1). We evaluated clinical and pathological characteristics and the expression of seven immunohistochemical markers related to proliferation/apoptosis, cell invasion/migration and metastasis.

Results: we studied 101 patients: 30 LACA, 44 SF and 27 M1. Locally advanced tumors presented larger dimensions and were associated with increased lymphocyte infiltration rates, lower levels of bax expression, and CD 44v6 when compared with SF and M1 groups. We observed significant differences between LACA and M1 in relation to colonic location, histology, lymph node status and bax and CD44v6 expression. We found differences were observed between the three groups for tumor size and lymphocytic infiltrate. Survival was similar in the LACA and SF groups (p=0.66) and was lower in the M1 group (p<0.001).

Conclusion: the data suggest that locally advanced colonic adenocarcinomas with adhesions between adjacent organs or structures represent a distinct entity.