The Accuracy and Clinical Significance of Histopathological Findings in the Submucosal Invasive front of Rectal Carcinoma, Obtained by Preoperative Transanal Punch biopsy

The purpose of the study was to clarify the correlation between histopathological findings in the submucosal invasive front of rectal carcinoma (front-p), which were taken by preoperative transanal punch biopsy, and those in the submucosal invasive front of the tumor edge in the resected specimen (front-sm). The find-ings in the deepest area of the vertical invasive front of cancer (front-d) were also examined. Seventy patients underwent preoperative punch biopsy and surgical resection of rectal cancer. Front-p, front-sm, and front-d were classified into two categories, respectively: the H-group, with one or more of the following unfavorable parameters: (1)immature tumor differentiation (por, sig or muc), (2) moderate or severe tumor bud-ding, (3) vessel permeation; and the L-group without these findings. As for this classification, front-p was significantly correlated with front-sm and front-d (p=0.0001, p=0.0009). Front-p was consistent with front-sm and front-d at 80% and 67%, respectively. H-groups in all the invasive fronts (Front-p, -sm, -d) showed a significantly higher incidence of Dukes C stage or hematogenous metastasis, and regional and lateral lymph node involvement. These data may indicate that preoperative transanal punch biopsy is useful to evaluate histological findings of the sm frontal region of rectal cancer, which represented tumor aggressiveness with good reliabiligy.