Table 1.
Study populations included in the meta‐analysis
| Study first author, year published | Location | Study design | n | Age, median, years | Sex | Follow‐up, median, months | DTC subtype, n (%) | |||
|---|---|---|---|---|---|---|---|---|---|---|
| F | M | Papillary | Follicular | Other | ||||||
| M. Kim, 2017 | Korea | Retrospective | 1,613 | 44 | 1,414 (88) | 199 (12) | 134 | 1,526 (95) | 87 (5) | 0 (0) |
| T.H. Kim, 2017 | Korea | Retrospective | 3,176 | 46 | 2,747 (86) | 429 (14) | 148 | 3,091 (97) | 85 (3) | 0 (0) |
| Shteinshnaider, 2018 | Israel | Retrospective | 433 | 47 | 327 (76) | 106 (24) | 116 | 386 (89) | 29 (7) | 18 (4) |
| Tam, 2018 | U.S. | Retrospective | 2,579 | 48 | 1,819 (71) | 760 (29) | 55 | 2,422 (94) | 126 (5) | 31 (1) |
| van Velsen, 2018 | The Netherlands | Retrospective | 792 | 49 | 545 (69) | 247 (31) | 86 | 628 (79) | 164 (21) | 0 (0) |
| Verburg, 2018 | Germany | Retrospective | 2,257 | 48 | 1,571 (70) | 686 (30) | 86 | 593 (26) | 1,663 (74) | 0 (0) |
| Pooled data | 10,850 | 44–49 years | 8,423 (78) | 2,427 (22) | 55–148 months | 8,646 (80) | 2,154 (19) | 49 (0.5) | ||
| Study first author, year published | Primary tumor size, n (%) | Extrathyroidal extension, n (%) | Lymph node metastasis, n (%) | Distant metastasis, n (%) | Surgery, n (%) | RAI, n (%) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| <2 cm | 2–4 cm | >4 cm | Present | None | Present | None | Present | None | Total | Partial | Yes | No | |
| M. Kim, 2017 | 1,020 (63) | 473 (29) | 1,]20 (7) | 816 (51) | 797 (49) | 901 (56) | 712 (44) | 39 (2) | 1,574 (98) | 1,312 (81) | 301 (19) | 1,264 (78) | 349 (22) |
| T.H. Kim, 2017 | 2,521 (79) | 536 (17) | 119 (4) | 1,814 (57) | 1,362 (43) | 1,116 (35) | 2,060 (65) | 43 (1) | 3,133 (99) | 2,922 (92) | 254 (8) | 2,724 (86) | 452 (14) |
| Shteinshnaider, 2018 | ND | ND | ND | 346 (80) | 87 (20) | 119 (27) | 314 (73) | 18 (4) | 415 (96) | 375 (87) | 58 (13) | 373 (86) | 60 (14) |
| Tam, 2018 | 1,720 (67) | 607 (24) | 228 (9) | 1,082 (42) | 1,497 (58) | 1,135 (44) | 1,444 (56) | 97 (4) | 2,482 (96) | 2,348 (91) | 231 (9) | 1,442 (58) | 1,054 (42) |
| van Velsen, 2018 | ND | ND | ND | ND | ND | ND | ND | ND | ND | 748 (97) | 25 (3) | 736 (93) | 56 (7) |
| Verburg, 2018 | ND | ND | ND | ND | ND | 1,767 (78) | 490 (22) | 203 (9) | 2,054 (91) | ND | ND | ND | ND |
| Pooled data | 5,261 (72) | 1,616 (22) | 467 (6) | 4,058 (52) | 3,743 (48) | 5,038 (50) | 5,020 (50) | 400 (4) | 9,658 (96) | 7,705 (90) | 869 (10) | 6,539 (77) | 1,971 (23) |
Clinical data in some categories were not available for all subjects in published studies, and therefore the sum of all columns will be less than the total study population.
Comparisons among study populations demonstrated significant differences for the following clinical parameters (p < .001, by chi‐square with Bonferroni correction for multiple comparisons): sex, DTC subtype, primary tumor size, extrathyroidal extension, lymph node metastasis, distant metastasis, surgery, and RAI.
Abbreviations: DTC, differentiated thyroid cancer; F, female; M, male; ND, no data; RAI, radioactive iodine therapy.