Context: Reliable prognostic factors are needed in papillary thyroid cancer patients to adapt initial therapy and follow-up schemes to the risks of persistent and recurrent disease. OBJECTIVE AND SETTINGS: To evaluate the respective prognostic impact of the extent of lymph node (LN) involvement and tumor extension beyond the thyroid capsule, we studied a group of 148 consecutive papillary thyroid cancer patients with LN metastases and/or extrathyroidal tumor extension. Initial treatment, performed at the Institut Gustave Roussy between 1987 and 1997, included in all patients a total thyroidectomy with central and ipsilateral en bloc neck dissection followed by radioactive iodine ablation.
Results: Uptake outside the thyroid bed, demonstrating persistent disease, was found on the postablation total body scan (TBS) in 22% of the patients. With a mean follow-up of 8 yr, eight patients (7%) with a normal postablation TBS experienced a recurrence. Ten-year disease-specific survival rate was 99% (confidence interval, 97-100%). Significant risk factors for persistent disease included the numbers of LN metastases (>10) and LN metastases with extracapsular extension (ECE-LN >3), tumor size (>4 cm), and LN metastases location (central). Significant risk factors for recurrent disease included the numbers of LN metastases (>10), ECE-LN (>3), and thyroglobulin level measured 6-12 months after initial treatment after T4 withdrawal.
Conclusion: We highlight an excellent survival rate and suggest risk classifications of persistent and recurrent disease based on the numbers of LN metastases and ECE-LN, LN metastases location, tumor size, and thyroglobulin level.