Stage-Dependent Death Hazard and Conditional Survival of Patients with Papillary Thyroid Cancer.

B Dear Editor: b The incidence of papillary thyroid cancer (PTC) has increased substantially worldwide in the recent decades.[1] Generally, PTC has an indolent course and a favorable prognosis, with a 10-year disease-specific survival (DSS) of more than 95%.[2] However, patients with distant metastases have a substantially lower 10-year DSS rate (~50%).[3] Moreover, since the 1980s, the incidence of differentiated thyroid cancer with distant metastasis has been steadily increasing in the United States.[3] Traditionally, survival rates are estimated from the time of diagnosis. The 5-year conditional DSS improved gradually in patients with lung metastasis, whereas it worsened in patients with bone metastasis farther from the diagnosis (Fig. The death hazard rate of patients with distant metastasis was higher than that of patients with localized or regional disease during the entire follow-up period (Fig. Among patients with single-site metastasis, patients with lung metastasis had the highest death hazard rate (0.07 [CI: 0.06-0.08]) during the first 2.5 years; thereafter, those with bone metastasis had the highest death hazard rate (0.08 [CI: 0.07-0.09]) (Fig. [Extracted from the article]