Objective: To determine the relationship between stimulated serum thyroglobulin levels (taken 3 months after total thyroidectomy) and tumor stage and recurrence in patients with well-differentiated thyroid carcinoma.
Study design: Retrospective chart review in a tertiary care institution.
Methods: Two hundred thirteen consecutive patients with well differentiated thyroid carcinoma treated between 1983 and 1998 were identified. Data were collected on clinicopathological variables, stimulated serum thyroglobulin levels obtained 3 months after total thyroidectomy prior to 131I therapy and recurrence.
Results: A high postoperative thyroglobulin level was significantly associated with advanced-stage disease at presentation (P =.005, Kruskall-Wallis) but not with any of the other clinicopathological variables. Patients with a thyroglobulin level greater than 20 pmol/L had a significantly increased risk of disease recurrence on univariate analysis (n = 213 [P =.0001, log rank test]), and in the Cox proportional-hazards model, both advanced tumor stage (P =.001, relative hazard, 3.4 [95% confidence interval [CI]: 2.4-4.9]) and a thyroglobulin level greater than 20 pmol/L (P =.001, relative hazard, 5.1 [95% CI: 2.0-13.1]) were significant predictors of recurrence. No other variables significantly altered the hazards model.
Conclusions: Advanced tumor stage at diagnosis and a stimulated thyroglobulin level greater than 20 pmol/L taken 3 months after total thyroidectomy were independent predictors of disease recurrence. Patients with a thyroglobulin level greater than 20 pmol/L are at increased risk of recurrence and may be candidates for more intensive follow-up or additional treatment.