Papillary thyroid carcinoma: 35-year outcome and prognostic factors in 1858 patients

Papillary thyroid carcinoma (PTC) is universally regarded as a curable malignancy with a favorable prognosis. However, a minority of patients may present, or subsequently develop, locoregional and distant metastases that may adversely affect survival. The value of the various staging methods is complicated by different approaches to diagnostic, therapeutic and follow-up strategies. We aimed at assessing the prognostic factors and survival rate in a large cohort of patients treated and followed up in the same center.

A total of 1858 patients with PTC operated on by the same surgeon, and followed in the same center over a period of 35 years, were included. Total thyroidectomy was performed in the majority of patients after I-131 diagnostic scans and thyroglobulin assays. When the latter 2 were positive, therapy with I-131 was given. Follow-up was performed periodically and further therapy doses were administered when necessary. All patients were maintained on life-long thyroxine.

Ninety-three patients (5%) developed evidence of locoregional or distant metastases after an average follow-up period of 7.9 years (range 1.53-30.5 years). Univariate analysis showed all variables (except for gender) to be significantly correlated with disease recurrence and survival. Multivariate analysis showed 4 variables to be significant and independent prognostic factors: patient age at first treatment, extent of disease, extent of surgery, and the presence of I-131 positive metastases.

Our data agree with other scoring systems in that patient age at first treatment and the extent of disease are significant and independent prognostic factors. However, and at variance with other methods, we found that the extent of primary surgery and the presence of I-131 positive or negative metastases have similar prognostic significance. In high risk patients, total thyroidectomy and lymphadenectomy followed by I-131 treatment and TSH-suppressive hormonal therapy are recommended.