Table 1. The characteristics of included studies.
| Author | Year | Country | Center | Recruitment period | No. of patients, type 1/ type 2, n | Median follow-up, months | Oncological outcome, HR | Cox Analysis | NOS score |
|---|---|---|---|---|---|---|---|---|---|
| Delahunt (12) | 2001 | New Zealand | Single | N.A. | 52/16 | 60 | OS | M | 6 |
| Mejean (3) | 2003 | France | Single | 1985–1998 | 56/32 | 26.6 | OS | U | 6 |
| Allory (13) | 2003 | France | Single | 1992–1998 | 26/13 | 43 | OS | M | 6 |
| Pignot (14) | 2007 | France | Single | 1995–2004 | 68/62 | 48 | OS, DFS | U, M | 7 |
| Waldert (15) | 2008 | Austria | Single | 1994–2007 | 34/62 | 42.3 | CSS | U | 6 |
| Gontero (16) | 2008 | Italy | Single | 1989–2002 | 14/31 | 84.5 | OS | U, M | 7 |
| Margulis (17) | 2008 | USA | Single | N.A. | 62/61 | 22.2 | CSS | U | 6 |
| Klatte (18) | 2009 | USA | Single | 1985–2007 | 51/107 | 38 | DFS | U, M | 6 |
| Ku (19) | 2009 | Korea | Single | 1995–2005 | 33/37 | 31.0/12.0* | CSS | U, M | 7 |
| Sukov (20) | 2012 | USA | Single | 1970–2002 | 252/143 | 136.8 | CSS | U, M | 7 |
| Pichler (21) | 2013 | Austria | Single | 1984–2007 | 88/89 | 93.8 | OS, DFS | U, M | 7 |
| Hutterer (22) | 2013 | Austria | Single | 1984–2007 | 87/89 | 68.3 | CSS | M | 6 |
| Cornejo (23) | 2015 | USA | Single | 1984–2010 | 112/42 | 73.9 | OS, CSS | U | 6 |
| Ledezma (7) | 2016 | USA | multiply | 2002–2012 | 373/253 | 41 | OS, CSS, RFS | U, M | 8 |
| Ha (24) | 2017 | Korea | multiply | 1988–2011 | 118/156 | 38 | OS, CSS, RFS | U, M | 7 |
| Bigot (6) | 2016 | French | multiply | 2004–2014 | 369/117 | 35 | CSS | U | 6 |
| Bellut (25) | 2017 | Germany | multiply | 1993–2007 | 113/39 | 98.2 | OS, CSS | U | 6 |
| Polifka (8) | 2019 | Germany | multiply | 1993–2007 | 246/130 | 38 | OS | U, M | 6 |
| Wong (26) | 2019 | USA | multiply | 2011–2018 | 337/172 | 21.6/22.8* | OS, RFS | U, M | 7 |
| Ren (27) | 2020 | China | Single | 2010–2017 | 39/49 | 46.08 | CSS | U, M | 6 |
| Pan (28) | 2020 | China | Single | N.A. | 42/60 | 61.4 | CSS | U, M | 6 |
| Yang (9) | 2020 | USA | Single | 1996–2017 | 117/45 | 59 | OS, DFS | U, M | 7 |
*, the follow-up time is respective according to the histologic subtype of PRCC, that is type 1/type 2. CSS, cancer-specific survival; DFS, disease-free survival; M, multivariate analysis; N.A., not available; OS, overall survival; NOS, Newcastle–Ottawa scale; RFS, recurrence-free survival; U, univariate analysis.