Thyroglobulin Levels as a Predictor of Papillary Cancer Recurrence After Thyroid Lobectomy.

[BACKGROUND/AIM] The effectiveness of using serum thyroglobulin (TG) to predict thyroid cancer recurrence after a thyroid lobectomy is unknown. This study aimed to evaluate the predictive nature of serum TG and TG trends after thyroid lobectomies.

[PATIENTS AND METHODS] We analyzed 514 papillary thyroid cancer (PTC) patients. The pre-, low-, high, and last-TG levels were reviewed and stratified into three groups. An ascending TG trend was defined if the last-TG level was more than 200% as high as the value of low-TG level. A descending trend was defined if the last-TG level decreased by more than 50% and a flat trend as between them.

[RESULTS] During a median follow-up period of 73.0 months, there were 21 (4.1%) recurrences. Most patients showed a descending (54.1%) or flat (35.6%) TG trend, but 10.3% of patients showed an ascending TG trend. Overall and lateral recurrences were significantly higher in the ascending TG group, indicating that an ascending TG trend was a good predictor for recurrence. Other factors such as positive node ratio (PNR), patient risk, age, and sex were not significant risk factors. In a Kaplan-Meier analysis, ascending TG trend was a good predictor of lateral recurrence.

[CONCLUSION] TG levels as a predictor of papillary cancer recurrence after thyroid lobectomy were found to be poor classifiers, and optimal cut-off values were not verified. An ascending TG trend was a good predictor of lateral recurrence. Further studies are warranted to investigate whether an ascending TG trend was due to an incomplete thyroid lobectomy or if the cancer had already metastasized to the lateral compartment.