Background: To evaluate the results of treatment and the prognostic variables of papillary thyroid carcinoma patients after long-term follow-up.
Patients and methods: Retrospective review of 1,373 thyroid cancer patients. Of the 1,016 papillary thyroid cancer patients, 394 patients received follow-up for more than 5 years, including 305 women (mean age, 38.4 +/- 13.7 years) and 89 men (mean age, 44.0 +/- 13.4 years). Of these papillary thyroid carcinoma patients, 227, 76, 68, and 23 patients were categorized in clinical stages I, II, III, and IV, respectively, at the time of diagnosis.
Results: After treatment, 36 (9.1%) patients died. Only 23 (5.8%) of them died of papillary thyroid carcinoma. The 1-, 5-, 10-, and 20-year survival rates were 0.980, 0.951, 0.901, and 0.731. Mortality factors of the papillary thyroid carcinoma patients related to age, gender, tumor size, and postoperative serum thyroglobulin (Tg) levels. Twenty-four patients progressed from clinical stages I, II, and III to stage IV during the follow-up period. Of these 24 patients, 12 died during the follow-up period. In this study, age, gender, 131I accumulated dose, postoperative serum Tg levels, and the survival rate were demonstrated to be statistically significant between the patients in early stage and advanced stage groups after treatment.
Conclusion: Twenty-four of the 47 papillary thyroid cancer patients with distant metastases were diagnosed during the follow-up period. This study suggests that distant metastasis may occur at a serum Tg level of 2.3 ng/mL with thyroxine replacement. Postoperative long-term close follow-up of these patients is recommended.