The prognostic value of cell proliferation in colorectal adenomas assessed with tritiated thymidine and anti-proliferating cell nuclear antigen.

We analyze the cell kinetics of colorectal adenomas by tritiated thymidine (3HTdR) autoradiographic method and anti-proliferating cell nuclear antigen (PCNA) antibodies. A total of 46 patients who underwent prior endoscopic polypectomy for colorectal adenomas were reevaluated by colonoscopy for 4 years. Thymidine labeling index (T-LI) in index adenomas ranged from 1.40 to 38.0% (median value: 10. 75%); PCNA labeling index (PCNA-LI) in index adenomas ranged from 0 to 27.0% (median value: 1.95%). Among the 46 patients studied, 16 developed recurrent adenomas (Group A) and 30 were free of recurrent adenomas (Group B). The T-LI and PCNA-LI comparisons between Groups A and B were statistically significant (p < 0.0001, chi2 test). These results demonstrate that T-LI and PCNA-LI in colorectal adenomas might be helpful to predict the development of metachronous adenomas and hence to plan the follow-up of patients with adenomatous polyps after polypectomy.