INCIDENCE OF EXTRAMURAL VENOUS INVERSION IN COLORECTAL-CARCINOMA - FINDINGS WITH A NEW TECHNIQUE

in reported studies of extramural venous invasion (EVI) by colorectal carcinoma (CRC) in which conventional preparations involving a section ing plane perpendicular to the tumor were used, an incidence as high a s 36% has been found for unselected surgical material from patients op erated on for cure. However, with this preparation technique, not all of the veins that exit the bowel wall roughly at right angles can be e xamined adequately. We investigated whether preparation of the adjacen t vascular connective tissue with tangential sectioning might not resu lt in different EVI rates. A total of 100 unselected surgical specimen s of the bowel bearing 103 CRCs were prepared using a previously undes cribed method, and EVI was found in 54.1% of the cases considered to h ave been treated curatively. To assess EVI fully, a complete study of all the vessels draining the tumor would be required yet the conventio nal preparation technique is associated with the distinct possibility of sampling error, because only a few vessels in each block are sectio ned in the longitudinal axis. This sampling error might well be the ex planation for the considerably higher incidence of EVI in our cases th an in the reports in the literature. in all patients with EVI, the pos sibility of hematogenous metastases exists, and this has a significant bearing on the question of selecting patients for adjuvant chemothera py. Copyright (C) 1996 by W.B. Saunders Company