Table 1. Baseline characteristics of the included studies.
| studies | tumor type | treatment | region | sample | Inclusion period | NLR/time obtained | outcomes | NOS |
|---|---|---|---|---|---|---|---|---|
| Albisinni 2019 [15] | bladder cancer | CR | Belgium | 134 | 2013–2018 | 5.58/ 1 month | OS, DFS | 8 |
| Bojaxhiu 2018 [16] | head and neck cancer | R, RC | Switzerland | 186 | 2007–2010 | 3.28/ <10 days | OS, DFS | 6 |
| Cui 2020 [17] | colorectal cancer | R | China | 146 | 2011–2014 | 2.96/≥7 days | DFS | 7 |
| Guo 2018 [18] | colorectal cancer | R | China | 135 | 2009–2014 | 3.64/>1 month | OS, DFS | 7 |
| Hayama 2020 [19] | colorectal cancer | CR | Japan | 176 | 2012–2016 | 3.1/ 7th day | DFS | 6 |
| He 2017 [20] | synchronous colorectal cancer | CR | China | 114 | 2009–2013 | 10.5/≤3 days | OS, DFS | 6 |
| Hoshimoto 2020 [21] | pancreatic cancer | R | Japan | 211 | 1995–2016 | 1.8/ 18–86 days | OS | 7 |
| Jakubowska 2020 [22] | colorectal cancer | R | Poland | 144 | 2014–2016 | 3.3/ 3 days | DFS | 6 |
| Jang 2017 [23] | prostate cancer | CR | Korea | 2302 | 2000–2010 | 3.5/ 2–3 months | OS | 7 |
| Jin 2016 [24] | non-small cell lung cancer | R | China | 123 | 2007–2010 | 3.9/ >1 month | OS, DFS | 8 |
| Kang 2016 [9] | bladder cancer | CR | Korea | 385 | 1999–2012 | 2/ 3–4 month | OS | 7 |
| Kim 2019 [25] | pancreas adenocarcinoma | CRC | Korea | 178 | 2010–2018 | 2.535/ 1 months | OS, DFS | 6 |
| Kim 2012 [26] | stomach cancer | R | Korea | 93 | 2004–2009 | 7.7/ third day | DFS | 8 |
| Li 2018 [27] | colon cancer | CR | China | 344 | 2012–2015 | 3/ 1–3 months | OS | 6 |
| Lin 2019 [28] | oropharyngeal cancer | R/RR | USA | 108 | 1997–2017 | 6.2/ 3 months | OS, DFS | 6 |
| Lin 2018 [29] | palatine tonsil cancer | RR | USA | 99 | 1997–2013 | 11.875/<2.5 months | OS | 6 |
| Miyatani 2018 [30] | gastric cancer | CR | Japan | 280 | 2001–2013 | 1.8/ 1 month | OS | 6 |
| Nishihara 2019 [31] | upper tract urothelial carcinoma | CR | Japan | 134 | 2004–2015 | 2.5/ 1–2 month | OS | 8 |
| Ohno 2012 [32] | clear cell renal cell carcinoma | R | Japan | 250 | 1990–2008 | 2.7/ 3 months | DFS | 6 |
| Paik 2014 [33] | colorectal cancer | R | Korea | 600 | 2006–2009 | 5/ NA | OS | 7 |
| Pu 2019 [34] | pancreatic ductal adenocarcinoma | R | China | 97 | 2012–2016 | 14.1/ NA | OS, DFS | 7 |
| Shibutani 2015 [35] | colorectal cancer | CR | Japan | 254 | 2006–2011 | 3/ 29 (23–36) days | OS | 7 |
| Tanaka 2018 [36] | gastric cancer | RC | Japan | 170 | 2006–2015 | 1.99/ NA | DFS | 6 |
| Zhou 2016 [10] | gastric cancer | CR/CRC | China | 360 | 2006–2008 | 6.19/≥5 days | OS | 8 |
| Zhou 2018 [37] | colorectal cancer | R | China | 516 | 2007–2015 | 2.41/ 1 month | OS, DFS | 7 |
CR, curative resection; CRC, curative resection and chemotherapy; R, resection; RR, resection and radiotherapy; RC, resection and chemotherapy; NLR, neutrophil-lymphocyte ratio; OS, overall survival; DFS, disease-free survival; NOS, Newcastle–Ottawa scale; NA, not available.