Appropriateness of the revised Japanese guidelines' risk classification for the prognosis of papillary thyroid carcinoma: a retrospective analysis of 5,845 papillary thyroid carcinoma patients.

The revised Japan Association of Endocrine Surgeons (JAES)/Japanese Society of Thyroid Surgery (JSTS) guidelines for patients with papillary thyroid carcinoma (PTC) describe four risk classes: very-low-risk, low-risk, intermediate-risk, and high-risk. Here we conducted a retrospective analysis to evaluate the appropriateness of these guidelines' risk classification of PTCs. Lymph node recurrence-free, distant recurrence-free and cause-specific survivals at 15-year of high-risk group were significantly poorer than those at 15-year of intermediate-group and these survivals of intermediate-group were poorer than of low- or very-low-risk patients. In the subset analyses based on patient age (≥55 years and <55 years), we obtained the same results in both subsets. Age significantly worsen the whole prognosis of high-risk patients and cause-specific survival of intermediate-risk patients, but not the prognosis of low- or very-low-risk patients. Therefore, the risk classification of the revised JAES/JSTS guidelines is appropriate, and therapeutic strategies should be decided based on the risk class together with the patients' age.