Cohort Characteristics
| Characteristic | No. of patients |
| Sex | |
| Men | 637 |
| Women | 1,791 |
| Age at diagnosis | |
| <45 y | 1,059 |
| ≥45 | 1,369 |
| Histology | |
| PTC | 1,823 |
| FTC | 570 |
| PDTC | 35 |
| AJCC–UICC (seventh edition) classification | |
| I | 1,577 |
| II | 306 |
| III | 300 |
| IVA | 95 |
| IVC | 150 |
| Surgery | |
| Thyroidectomy | 2,196 |
| Subtotal thyroidectomy | 194 |
| Hemithyroidectomy | 36 |
| Microdissection | 2 |
| Neck dissection | 969 |
| 131I therapy | |
| All | 2,213 |
| PTC | 1,613 |
| FTC | 566 |
| PDTC | 34 |
| Residual status after surgery | |
| R0 | 2,265 |
| R1 | 128 |
| R2 | 35 |
| Distant metastases | 234 (270 sites) |
| Lung | 162 |
| Bones | 68 |
| Brain | 19 |
| Mediastinal lymph nodes | 14 |
| Liver | 6 |
| Kidney | 1 |
| Recurrence | 21 (27 sites) |
| Thyroid | 9 |
| Local lymph nodes | 13 |
| Distant metastases | 5 |
R0 = no residual; R1 = microscopic residual; R2 = macroscopic residual.