Table 1.
Characteristics of the sample population.
| Variable | Total | Without prior thyroid cancer (n = 1420) | With prior thyroid cancer (n = 142) | Statistics | P-value |
|---|---|---|---|---|---|
| Age, mean ± SD | 65.45 ± 10.83 | 65.45 ± 10.71 | 65.49 ± 12.04 | t = -0.04 | 0.967 |
| Gender, n (%) | χ2 = 23.152 | < 0.001 | |||
| Female | 510 (32.65) | 438 (30.85) | 72 (50.70) | ||
| Male | 1052 (67.35) | 982 (69.15) | 70 (49.30) | ||
| Race, n (%) | χ2 = 6.513 | 0.039 | |||
| White | 1029 (65.88) | 924 (65.07) | 105 (73.94) | ||
| Black | 163 (10.44) | 156 (10.99) | 7 (4.93) | ||
| Others | 370 (23.69) | 340 (23.94) | 30 (21.13) | ||
| Marital status, n (%) | χ2 = 3.639 | 0.056 | |||
| Married | 827 (52.94) | 741 (52.18) | 86 (60.56) | ||
| Not married | 735 (47.06) | 679 (47.82) | 56 (39.44) | ||
| Tumor size, n (%) | χ2 = 10.555 | 0.005 | |||
| < 5 cm | 696 (44.56) | 634 (44.65) | 62 (43.66) | ||
| ≥ 5 cm | 538 (34.44) | 475 (33.45) | 63 (44.37) | ||
| Unknown | 328 (21.00) | 311 (21.90) | 17 (11.97) | ||
| Regional nodes positive, n (%) | χ2 = 7.377 | 0.025 | |||
| Yes | 21 (1.34) | 18 (1.27) | 3 (2.11) | ||
| No | 54 (3.46) | 43 (3.03) | 11 (7.75) | ||
| Unknown | 1487 (95.20) | 1359 (95.70) | 128 (90.14) | ||
| The primary site, n (%) | χ2 = 3.915 | 0.048 | |||
| C22.0-Liver | 1387 (88.80) | 1268 (89.30) | 119 (83.80) | ||
| C22.1-Intrahepatic bile duct | 175 (11.20) | 152 (10.70) | 23 (16.20) | ||
| Radiation therapy, n (%) | χ2 = 8.556 | 0.003 | |||
| None / Unknown | 1479 (94.69) | 1352 (95.21) | 127 (89.44) | ||
| Yes | 83 (5.31) | 68 (4.79) | 15 (10.56) | ||
| Surgery, n (%) | χ2 = 11.196 | < 0.001 | |||
| None / Unknown | 1152 (73.75) | 1064 (74.93) | 88 (61.97) | ||
| Surgery performed | 410 (26.25) | 356 (25.07) | 54 (38.03) | ||
| Chemotherapy, n (%) | χ2 = 0.287 | 0.592 | |||
| None / Unknown | 913 (58.45) | 827 (58.24) | 86 (60.56) | ||
| Yes | 649 (41.55) | 593 (41.76) | 56 (39.44) | ||
| Histologic grade, n (%) | Fisher | < 0.001 | |||
| Grade I | 130 (8.32) | 107 (7.54) | 23 (16.20) | ||
| Grade II | 292 (18.69) | 259 (18.24) | 33 (23.24) | ||
| Grade III | 136 (8.71) | 119 (8.38) | 17 (11.97) | ||
| Grade IV | 9 (0.58) | 8 (0.56) | 1 (0.70) | ||
| Unknown | 995 (63.70) | 927 (65.28) | 68 (47.89) | ||
| AJCC T status, n (%) | χ2 = 12.204 | 0.016 | |||
| T1 | 533 (34.12) | 469 (33.03) | 64 (45.07) | ||
| T2 | 262 (16.77) | 240 (16.90) | 22 (15.49) | ||
| T3 | 264 (16.90) | 242 (17.04) | 22 (15.49) | ||
| T4 | 63 (4.03) | 55 (3.87) | 8 (5.63) | ||
| Unknown | 440 (28.17) | 414 (29.15) | 26 (18.31) | ||
| AJCC N status, n (%) | χ2 = 9.210 | 0.010 | |||
| N0 | 1071 (68.57) | 964 (67.89) | 107 (75.35) | ||
| N1 | 107 (6.85) | 93 (6.55) | 14 (9.86) | ||
| Unknown | 384 (24.58) | 363 (25.56) | 21 (14.79) | ||
| AJCC M status, n (%) | χ2 = 7.562 | 0.023 | |||
| M0 | 1102 (70.55) | 997 (70.21) | 105 (73.94) | ||
| M1 | 177 (11.33) | 155 (10.92) | 22 (15.49) | ||
| Unknown | 283 (18.12) | 268 (18.87) | 15 (10.56) | ||
| SEER historic stage, n (%) | χ2 = 16.737 | < 0.001 | |||
| Localized | 672 (43.02) | 599 (42.18) | 73 (51.41) | ||
| Regional | 367 (23.50) | 341 (24.01) | 26 (18.31) | ||
| Distant | 174 (11.14) | 149 (10.49) | 25 (17.61) | ||
| Unknown | 349 (22.34) | 331 (23.31) | 18 (12.68) | ||
| Survival month, M (Q1,Q3) | 11.00 (4.00,20.00) | 11.00 (4.00,19.00) | 14.00 (7.00,39.00) | Z = 4.959 | < 0.001 |
| Vital status, n (%) | χ2 = 5.418 | 0.020 | |||
| Alive | 638 (40.85) | 593 (41.76) | 45 (31.69) | ||
| Dead | 924 (59.15) | 827 (58.24) | 97 (68.31) | ||
| SEER cause death classification, n (%) | χ2 = 24.399 | < 0.001 | |||
| Alive | 638 (40.85) | 593 (41.76) | 45 (31.69) | ||
| Death due to liver cancer | 714 (45.71) | 655 (46.13) | 59 (41.55) | ||
| Death due to other cause | 210 (13.44) | 172 (12.11) | 38 (26.76) | ||
AJCC American Joint Committee on Cancer, SEER the Surveillance, Epidemiology, and End Results.