A high Ki-67 labeling index and high thyroglobulin doubling rate are significant predictors of excision-site recurrence of papillary thyroid carcinoma following airway resection for locally curative surgery

Abstract

Background: Papillary thyroid carcinoma (PTC) occasionally invades the trachea and requires airway resection. Tracheal excision site recurrence (ESR) is a serious problem. We investigated predictors of ESR in patients with PTC who underwent airway resection for locally curative surgery.

Methods: We enrolled 149 patients with PTC who underwent airway resection (median age at the initial surgery: 67 years), including partial-thickness resection (n = 73) or full-thickness resection (n = 76), for grossly curative surgery. The median postoperative follow-up period was 93 months.

Results: To date, 11 patients (6.7%) underwent ESR: 6 underwent full-thickness resection and 5 underwent partial-thickness resection. The time to ESR ranged from 14 to 113 months (median: 57 months) after the initial surgery. None of the 11 ESR patients underwent adjuvant external beam radiotherapy (EBRT) and none of the 4 airway resection patients who underwent EBRT developed ESR. The 5- and 10-year ESR rates were 4.3% and 11.3%, respectively. In the multivariate analysis (forward-backward stepwise selection method), a Ki-67 labeling index (LI) ≥5% (p = 0.048) and the thyroglobulin doubling rate (Tg-DR) >0.33/year (p = 0.009) (for Tg-antibody negative cases) were independent predictors of ESR. Nine of the 11 patients underwent ESR resection and only one developed a second recurrence.

Conclusions: A high Ki-67 LI was a static predictor, and high Tg-DR was a dynamic predictor, of ESR in patients with PTC following airway resection. In such patients, careful postoperative monitoring for ESR is necessary and adjuvant therapies, such as EBRT, may be considered.

Keywords: Ki‐67 LI; papillary thyroid carcinoma; prognosis; thyroglobulin doubling rate; tracheal invasion.