Evaluating the risk of re-recurrence in patients with persistent/recurrent thyroid carcinoma after initial reoperation.

Abstract

Although the 2015 American Thyroid Association guidelines proposed initial and response-to-therapy risk stratifications were adequately validated in untreated papillary thyroid cancer patients, it is still unknown how they work in persistent/recurrent papillary thyroid cancer patients. This study aimed to evaluate and revise the stratifications in these patients. This retrospective study included patients who received the first reoperation with complete thyroid resection but without radioactive iodine ablation. Stratifications were performed considering the persistent/recurrent tumor characteristics and thyroglobulin levels 1 to 6 months after reoperation and then revised with new prognostic factors and adjusted thyroglobulin cutoff values, respectively. Prognostic performance was evaluated with Kaplan-Meier curves, proportion of variation explained, and Harrell's concordance index. Among a total of 232 patients, 5-year re-recurrence free survival rates were 92.4%, 86.2%, and 74.5% in low-, intermediate-, and high-risk patients, respectively (all P > .05) and 97.0%, 96.3%, and 81.6% in excellent response, intermediate response, and biochemical incomplete response groups, respectively (excellent response versus intermediate response, P > .05; intermediate response versus biochemical incomplete response, P < .05). After incorporating age at reoperation, recurrent primary size, and recurrent lymph node number, the high-risk group had significantly compromised re-recurrence free survival versus the intermediate-risk group (76.2% vs 91.6%). After adjusting thyroglobulin values, 5-year re-recurrence free survival rates were 96.4%, 85.9%, and 75.8% in excellent response (<1 ng/mL), intermediate response (1-10 ng/mL), and biochemical incomplete response (≥10 ng/mL) groups, respectively (all P < .05), with a higher proportion of variation explained (12.8% vs 10.1%) and concordance index (0.669 vs 0.615) compared with the American Thyroid Association version. The revised American Thyroid Association initial and response-to-therapy risk stratifications have acceptable predictive value for persistent/recurrent papillary thyroid cancer patients.