Table 6.
Characteristics of the radiogenic papillary thyroid microcarcinomas by thyroid surgery extent.
| Total thyroidectomy, n=405 | Organ-preserving, n=60 | p-value | OR or HR (95% CI) | p-value | |
|---|---|---|---|---|---|
| Parameters | number or value (% or IQR or SD) | number or value(% or IQR or SD) | univariate | multivariate a | |
| Sex, F/M (%M, F:M ratio; ref=F) | 323/82; 20.2%; 1.8:1 | 44/16; 26.7%; 2.8:1 | 0.308 | 0.729 (0.389-1.365) b | 0.324 |
| Age at operation, years | 35.3 (30.1-40.2) | 34.1 (29.3-36.7) | 0.074 | 1.024 (0.990-1.059) c | 0.176 |
| Age at exposure, years | 9.2 (5.0-13.9) | 7.4 (3.5-13.2) | 0.199 | 1.034 (0.982-1.089) c | 0.200 |
| Latency period, years | 26.1 (22.6-29.2) | 26.7 (21.7-28.8) | 0.866 | 1.017 (0.968-1.069) c | 0.501 |
| Radiation dose to the thyroid, mGy | 46.8 (29.5-110.7) | 46.0 (26.1-113.7) | 0.487 | 1.215 (0.954-1.548) c | 0.115 |
| Probability of causation, % | 19.2 (8.7-47.0) | 18.7 (7.3-44.3) | 0.701 | 1.000 (0.990-1.011) d | 0.934 |
| ≤ 25% | 229 (56.5%) | 32 (53.3%) | 0.677 | 1.138 (0.661-1.961) d | 0.640 |
| > 25 – 50% | 86 (21.2%) | 15 (25.0%) | 0.505 | 0.899 (0.656-1.233) d | 0.510 |
| > 50 – 75% | 57 (14.1%) | 10 (16.7%) | 0.559 | 0.936 (0.732-1.195) d | 0.594 |
| > 75 – 100% | 33 (8.1%) | 3 (5.0%) | 0.603 | 1.139 (0.841-1.544) d | 0.399 |
| Tumor size, mm | 8 (6-9) | 7 (6-8) | 0.013 | 1.225 (1.044-1.439) | 0.013 |
| lesser or equal median | 202 (49.9%) | 40 (66.7%) | 0.018 | 0.498 (0.281-0.883) | 0.017 |
| greater than median | 203 (50.1%) | 20 (33.3%) | 0.018 | 2.007 (1.132-3.559) | 0.017 |
| Full tumor capsule | 55 (13.6%) | 25 (41.7%) | 1.00E-06 | 0.223 (0.124-0.404) | 6.91E-07 |
| Dominant growth pattern | 0.106 | 0.704 (0.516-0.962) e | 0.028 | ||
| papillary | 205 (50.6%) | 22 (36.7%) | 0.052 | 1.807 (1.029-3.171) | 0.039 |
| follicular | 82 (20.2%) | 14 (23.3%) | 0.609 | 0.878 (0.458-1.683) | 0.694 |
| solid-trabecular | 118 (29.2%) | 24 (40.0%) | 0.099 | 0.573 (0.325-1.011) | 0.054 |
| Ki-67 labeling index, n=92 | n=85; 4.6 (2.9-7.2) | n=7; 4.2 (3.2-6.4) | 0.854 | 1.042 (0.814-1.333) | 0.745 |
| 0 – 5% | 48 (56.5%) | 4 (57.1%) | 1,000 | 1.002 (0.204-4.915) | 0.998 |
| >5 – 10% | 31 (36.5%) | 3 (42.9%) | 0.707 | 0.746 (0.153-3.653) | 0.718 |
| >10% | 6 (7.0%) | 0 | 1,000 | 1.349 (0.315-5.774) | 0.686 |
| BRAFV600E -positive, n=95 | n=88; 60 (68.2%) | n=7; 4 (57.1%) | 0.679 | 0.972 (0.143-6.623) | 0.977 |
| Oncocytic changes | 177 (43.7%) | 24 (40.0%) | 0.676 | 1.071 (0.608-1.888) | 0.812 |
| Multifocality | 98 (24.2%) | 5 (8.3%) | 0.004 | 3.389 (1.316-8.725) | 0.011 |
| Lymphatic/vascular invasion | 107 (26.4%) | 9 (15.0%) | 0.057 | 2.175 (1.028-4.600) | 0.042 |
| Extrathyroidal extension (any) | 62 (15.3%) | 2 (3.3%) | 0.008 | 5.555 (1.317-23.430) | 0.020 |
| T category | |||||
| pT1a | 398 (98.3%) | 60 (100%) | 0.602 | 0.432 (0.020-9.395) | 0.593 |
| pT3b | 7 (1.7%) | 0 | 0.602 | 2.314 (0.106-50.308) | 0.593 |
| N category (N1) | 90 (22.2%) | 0 | 2.00E-06 | 37.037 (2.268-500.000) | 0.011 |
| pN1a | 56 (13.8%) | 0 | 4.31E-04 | 20.706 (1.264-339.232) | 0.034 |
| pN1b | 34 (8.4%) | 0 | 0.014 | 11.425 (0.679-192.354) | 0.091 |
| M category (M1) | 4 (1.0%) | 0 | 1,000 | 1.723 (0.063-47.224) | 0.747 |
| Invasiveness score | 1 (0-1) | 0 (0-0) | 3.68E-06 | 3.026 (1.857-4.932) e | 9.00E-06 |
| 0 | 178 (44.0%) | 46 (76.7%) | 2.00E-06 | 0.235 (0.125-0.443) | 7.00E-06 |
| 1 | 129 (31.9%) | 12 (20.0%) | 0.071 | 1.813 (0.929-3.539) | 0.081 |
| 2 | 67 (16.5%) | 2 (3.3%) | 0.006 | 5.915 (1.407-24.861) | 0.015 |
| 3 | 26 (6.4%) | 0 | 0.036 | 9.950 (0.574-172.596) | 0.115 |
| 4 | 5 (1.2%) | 0 | 1,000 | 1.599 (0.067-38.201) | 0.772 |
| 5 | 0 | 0 | NA f | NA | NA |
| Concomitant thyroid cancer | 2 (0.5%) | 0 | 1,000 | 1.674 (0.040-70.712) | 0.787 |
| Concomitant nodular disease | 110 (27.2%) | 10 (16.7%) | 0.113 | 1.715 (0.832-3.537) | 0.144 |
| Concomitant Graves’ disease | 5 (1.2%) | 2 (3.3%) | 0.225 | 0.311 (0.058-1.659) | 0.171 |
| Chronic thyroiditis | 115 (28.4%) | 6 (10.0%) | 0.002 | 3.365 (1.396-8.111) | 0.007 |
| LN dissection performed | 182 (44.9%) | 10 (6.7%) | 1.90E-05 | 4.245 (2.0838.651) | 6.90E-05 |
| level ≥ 6 | 123 (30.4%) | 9 (15.0%) | 0.014 | 2.412 (1.149-5.064) | 0.020 |
| level 1 – 5 | 59 (14.6%) | 1 (1.7%) | 0.003 | 11.666 (1.571-86.662) | 0.016 |
| RIT performed | n=353; 87.2 | 0 | 1.18E-44 | 781.571 (49.263-inf) | 2.32E-06 |
| RIT cycles | 1 (1-1) | NA | NA | NA | NA |
| Cumulative RI activity, MBq | 3964 (2775-4360) | NA | NA | NA | NA |
| RIT response | n=353 | NA | NA | NA | NA |
| RAI-R recurrence vs other | 3 (0.8%) | NA | NA | NA | NA |
| excellent vs other | 332 (94.1%) | NA | NA | NA | NA |
| Follow-up, years | 5.3 (2.4-9.1) | 3.1 (1.2-7.9) | 0.047 | 1.057 (0.996-1.121) | 0.068 |
| Recurrence | 6 (1.5%) | 0 | 1,000 | 2.273 (0.100-51.806) g | 0.607 |
| Time to recurrence, yrs | 1.2 (1.1-1.6) | NA | NA | NA | NA |
| Recurrent metastases | n=6 | 0 | NA | NA | NA |
| Dominant growth pattern | |||||
| papillary | 5 (83.3%) | NA | NA | NA | NA |
| follicular | 1 (16.7%) | NA | NA | NA | NA |
| solid-trabecular | 0 | NA | NA | NA | NA |
| Ki67 labeling index | n=3; 1.2 | NA | NA | NA | NA |
| BRAFV600E -positive | n=3; 2 (66.7%) | NA | NA | NA | NA |
| Oncocytic changes | 3 (50.0%) | NA | NA | NA | NA |
| Cystic changes | 5 (83.3%) | NA | NA | NA | NA |
| RIT recurrence response | n=6 | NA | NA | NA | NA |
| RAI-R recurrence vs other | 3 (50.0%) | NA | NA | NA | NA |
| excellent vs other | 3 (50.0%) | NA | NA | NA | NA |
a
Adjusted for age at operation and sex unless otherwise specified.
b
Adjusted for age at operation.
c
Adjusted for sex.
d
Non-adjusted.
e
Polytomous logistic regression.
f
Not available.
g
The Firth’s-penalized Cox regression.
Numbers in bold indicate statistical significance.