Ki-67 and CK-19 are predictors of locoregional recurrence in papillary thyroid carcinoma

Most patients with papillary thyroid carcinoma have good prognosis; however, recurrence rates and the need of salvage treatment remain a significant problem for 5-40% of patients. Although several risk classifications based on clinicopathological prognostic factors are used, it is not possible to predict which patients will have a higher risk of recurrence. The objective of the study is to analyse the impact of cytokeratin-19 and Ki-67 immunoexpression as predictive markers of the risk of recurrence in papillary thyroid carcinoma. This is a retrospective case-control study, including 42 patients with papillary thyroid carcinoma and 42 controls. The groups were matched by gender, age and pathological staging T and N. Slides were made by the microarray tissue system. Multivariate logistic regression was applied to identify an independent risk factor for recurrence. Of the 42 selected cases, 30 patients (71.4%) were female and 12 (28.6%) were male, ranging in age from 10 to 80 years (median of 39 years). Most patients (64.3%) had tumors at initial T staging (T1-T2). Half of the sample was classified as low risk according to the American Thyroid Association (ATA) risk stratification. Follow-up time ranged from 46 to 196 months, with time to recurrence from 2 to 106 months (median, 30 months). CK-19 and Ki-67 immunoexpression had a statistically significant association with the risk of recurrence (p = 0.029 and p = 0.007, respectively). In multivariate logistic regression analysis, immunoexpression for these markers was an independent risk factor for locoregional recurrence (OR-9,64; CI-1.14-81.01 and OR-3,21; CI-1.32-7.94, respectively). The immunohistochemical analysis of the Ki-67 and CK-19 markers is useful to predict tumour recurrence in patients with papillary thyroid carcinoma.