Table 2. Cox proportional hazards regression model analysis of overall survival (OS) and disease-specific survival (DSS).
| Variables | OS | DSS | ||
|---|---|---|---|---|
| aHR (95% CI) | P-value | aHR (95% CI) | P-value | |
| Age at diagnosis, y | ||||
| < 20 | Reference | Reference | ||
| 20–44 | 1.005 (0.316,3.199) | 0.993 | 0.083 (0.005,1.345) | 0.080 |
| 45–64 | 4.280 (1.372,13.357) | 0.012 | 3.907 (0.532,28.692) | 0.180 |
| ≥ 65 | 15.848 (5.086,49.388) | P < 0.001 | 10.063 (1.372,73.807) | 0.023 |
| Sex | ||||
| Male | Reference | Reference | ||
| Female | 0.568 (0.499,0.647) | P < 0.001 | 0.548 (0.382,0.786) | 0.001 |
| Race | ||||
| White | Reference | Reference | ||
| Black | 1.571 (1.286,1.919) | P < 0.001 | 1.814 (1.003,3.281) | 0.049 |
| Grade | ||||
| Well | Reference | Reference | ||
| Moderately | 1.222 (0.845,1.768) | 0.287 | 0.596 (0.162,2.184) | 0.434 |
| Poorly | 2.007 (1.269,3.173) | 0.003 | 4.936 (2.106,11.566) | P < 0.001 |
| Undifferentiated | 10.128 (6.086,16.853) | P < 0.001 | 12.963 (5.358,31.361) | P < 0.001 |
| Surgery | ||||
| Total thyroidectomy | Reference | Reference | ||
| Less than a lobe | 1.544 (0.921,2.588) | 0.100 | 4.719 (1.671,13.330) | 0.003 |
| Lobectomy ONLY | 1.039 (0.827,1.306) | 0.742 | 1.325 (0.591,2.971) | 0.495 |
| Lobectomy WITH isthmus | 0.870 (0.650,1.166) | 0.352 | 0.234 (0.032,1.702) | 0.151 |
| Removal of a lobe and partial removal of the contralateral lobe | 0.803 (0.400,1.615) | 0.539 | 0.947 (0.131,6.858) | 0.957 |
| Subtotal or near total thyroidectomy | 0.980 (0.734,1.308) | 0.892 | 0.539 (0.170,1.710) | 0.294 |
| None | 5.840 (4.056,8.409) | P < 0.001 | 2.491 (1.120,5.542) | 0.025 |
| Radiotherapy | ||||
| None | Reference | Reference | ||
| Radioisotopes | 0.659 (0.573,0.758) | P < 0.001 | 0.794 (0.529,1.193) | 0.267 |
| Tumor size(mm) | ||||
| ≤ 10 | Reference | Reference | ||
| 11–20 | 1.043 (0.885,1.229) | 0.615 | 1.395 (0.744,2.615) | 0.299 |
| 21–40 | 1.093 (0.918,1.302) | 0.316 | 2.007 (1.107,3.615) | 0.022 |
| > 40 | 1.220 (0.988,1.505) | 0.065 | 2.989 (1.290,5.618) | 0.001 |
| Extension | ||||
| Single invasive tumor confined to thyroid | Reference | Reference | ||
| Multiple foci confined to thyroid | 0.997 (0.836,1.142) | 0.768 | 0.679 (0.349,1.320) | 0.254 |
| Into thyroid capsule | 1.040 (0.807,1.580) | 0.764 | 1.554 (0.724,3.336) | 0.258 |
| Beyond thyroid capsule | 1.297 (1.065,1.580) | 0.010 | 3.753 (2.154,6.538) | P < 0.001 |
| Lymph nodes metastases | ||||
| None | Reference | Reference | ||
| Yes | 1.357 (1.112,1.657) | 0.003 | 1.983 (1.278,3.077) | 0.002 |
| Distant metastases | ||||
| None | Reference | Reference | ||
| Yes | 3.956 (2.993,5.230) | P < 0.001 | 9.903 (6.252,15.687) | P < 0.001 |
*P values calculated by multivariate Cox analysis.
aHR: adjusted hazard ratio (adjusted for age at diagnosis, sex, race, grade, region, tumor size, laterality, extension, lymph nodes metastases, distant metastases, radiotherapy, and surgery).
CL: confidence interval.