Prognostic importance of histologic vascular invasion in papillary thyroid carcinoma.

Objective: To conduct a retrospective study of 39 patients with papillary carcinoma of the thyroid with histologic vascular invasion (VI+) and 361 patients without any sign of vascular invasion (VI-).

Summary Background Data: In the present study, we undertook a retrospective analysis of papillary carcinoma of the thyroid to assess whether histologically determined vascular invasion can be considered a predictive factor for prognosis.

Methods: By means of a retrospective study, we evaluated the department's database of patients with papillary thyroid carcinoma who had undergone total thyroidectomy from January 1993 to December 1999.

Results: Group I consisted of papillary carcinoma without any sign of vascular invasion (VI-) comprising 361 patients. Group II consisted of papillary carcinoma with vascular invasion (VI+) comprising 39 patients. At the time of diagnosis, we observed no metastases in patients with VI-, whereas a pulmonary metastasis was observed in 1 patient with VI+ (P = 0.0023). In 3.6% patients with VI- and in 20.5% patients with VI+, we observed recurrences in the regional lymph nodes (P < 0.001); we observed 6 (1.66%) distant metastases in patients with VI- and in the 12.8% patients with VI+ (P < 0.001). Three patients with VI+ (7.7%) and 2 patients with VI- (0.6%) died of tumor-related causes; these figures were found to be statistically significant (P < 0.001).

Conclusions: In papillary carcinoma, it should be noted that histologic vascular invasion may be considered as a sign of an increased tendency toward hematogenic invasion and consequent increase in the relative percentage of metastases; ultimately, this means a poorer prognosis. In the presence of risk factors indicating a possible increase in biologic aggressiveness, adequate postoperative treatment and close follow up become essential.