Table 1. Baseline characteristics of 42 included studies.
| Study | Country | Study period | Study design | No. of FNA | No. of patients | No. of surgery | Molecular testing |
|---|---|---|---|---|---|---|---|
| Ke 2019, (10) | China | 2011–2016 | Retro | 13,351 | 12,530 | 3,890 | No |
| Liu 2017, (11) | China | 2014–2017 | Retro | 2,838 | NA | 791 | No |
| Wu 2019, (12) | China | 2018 | Pros | 479 | 472 | 288 | Yes |
| Zhang 2015, (13) | China | 2014 | Pros | 220 | 220 | 159 | Yes |
| Arul 2015, (14) | India | 2012–2015 | Retro | 603 | NA | 392 | No |
| Garg 2017, (15) | India | 2013–2014 | Retro | 76 | 76 | 24 | No |
| Hemalatha 2018, (16) | India | 2010–2015 | Pros | 277 | 277 | 111 | Yes |
| Kannan 2017, (17) | India | 2016–2018 | Pros | 238 | 246 | 77 | No |
| Kumari 2019, (18) | India | NA | Pros | 1,050 | 1,050 | 111 | No |
| Mahajan 2017, (19) | India | 2010–2015 | Retro | 4,562 | NA | 334 | No |
| Mehra 2015, (20) | India | 2010–2012 | Pros | 225 | NA | 40 | No |
| Mondal 2013, (21) | India | 2009–2012 | Retro | 1,020 | NA | 323 | No |
| Roy 2019, (22) | India | 2015–2016 | Retro | 132 | 1,018 | 47 | No |
| Ronen 2019, (23) | Israel | 2013–2017 | Retro | 287 | 287 | 58 | No |
| Rosenblum 2019, (24) | Israel | 2013–2015 | Retro | 416 | 2,674 | 124 | No |
| Satoh 2017, (25) | Japan | 2015–2016 | Retro | 1,600 | NA | 522 | No |
| Choi 2014, (26) | Korea | 2008–2011 | Retro | 191 | 191 | 142 | No |
| Chung 2019, (27) | Korea | 2016 | Pros | 102 | 93 | 80 | No |
| Hwang 2015, (28) | Korea | 2012–2014 | Pros | 564 | NA | 86 | Yes |
| Hyeon 2014, (29) | Korea | 2011–2012 | Retro | 645 | NA | 231 | Yes |
| Kang 2012, (30) | Korea | 2008–2009 | Retro | 1,060 | 1,060 | 313 | Yes |
| Kim 2011, (31) | Korea | 2007–2009 | Pros | 865 | NA | 204 | Yes |
| Kim 2014, (32) | Korea | 2009–2011 | Retro | 114 | 114 | 8 | No |
| Kim 2017a, (33) | Korea | 2010–2011 | Retro | 35,073 | NA | 5,084 | No |
| Kim 2017b, (34) | Korea | 2010–2014 | Retro | 903 | NA | 210 | No |
| Kim 2018, (35) | Korea | 2012–2014 | Retro | 5,549 | 5,127 | 1,891 | No |
| Lee 2014, (36) | Korea | 2010–2012 | Retro | 363 | NA | 152 | No |
| Lee 2015, (37) | Korea | 2011–2012 | Retro | 757 | NA | 213 | No |
| Lee 2017a, (38) | Korea | 2013 | Retro | 1,925 | NA | 381 | No |
| Lee 2017b, (39) | Korea | 2014–2015 | Retro | 133 | 132 | 59 | No |
| Park 2013, (40) | Korea | 2011 | Retro | 120 | 120 | 83 | Yes |
| Yeo 2011, (41) | Korea | 2009–2010 | Retro | 983 | 973 | 209 | Yes |
| Yoo 2013, (42) | Korea | 2003–2009 | Retro | 66 | NA | 36 | No |
| Upadhyaya 2019, (43) | Nepal | 2009–2014 | Retro | 109 | NA | 49 | No |
| Al Dawish 2017, (44) | Saudi Arabia | 2012–2014 | Retro | 1,433 | 1,188 | 369 | No |
| Al-Abbadi 2013, (45) | Saudi Arabia | 2010–2011 | Retro | 205 | 186 | 64 | No |
| Alabdulqader 2015, (46) | Saudi Arabia | 2012–2013 | Retro | 252 | 218 | 45 | No |
| Mufti 2012, (47) | Saudi Arabia | 2005–2010 | Retro | 250 | NA | 85 | No |
| Gan 2017, (48) | Singapore | 2008–2014 | Retro | 309 | NA | 137 | No |
| Lim 2018, (49) | Singapore | 2008–2015 | Retro | 111 | 88 | 88 | No |
| Limlunjakorn 2017, (50) | Thailand | 2010–2015 | Retro | 2,762 | NA | 457 | No |
| Thewjitcharoen 2019, (51) | Thailand | 2010–2017 | Retro | 2,735 | 2,115 | 188 | No |
FNA, fine-needle aspiration; retro, retrospective; pros, prospective; NA, not available.