Tumor angiogenesis as an independent prognostic indicator in human papillary thyroid carcinoma.

Angiogenesis has been determined to play a very important role in either the growth of solid tumors or their recurrence in distant organs. Microvessels stained immunohistochemically for the factor VIII-related antigen were counted in one hundred patients with papillary thyroid carcinoma in order to clarify the association of tumor angiogenesis with the prognosis of the disease. The mean microvessel count (MVC) was significantly higher in tumors with distant recurrence than those without recurrence. Disease-free survival of patients with a high MVC (>/= 23) was significantly worse than that of patients with a low MVC (</= 22), as well as the overall survival. In multivariate analysis, the MVC was most strongly correlated with disease-free survival, and was independent of other prognostic factors. In conclusion, the MVC is a potent prognostic indicator in papillary thyroid carcinoma.