Table 1. Characteristics of included studies.
| Study | Year | Region | NOS score | Sample size | Age (years) median(range) | Stage | Treatment regimen | Study period | Cut-off | Outcomes analyzed |
|---|---|---|---|---|---|---|---|---|---|---|
| Porrata | 2010 | USA | 8 | 255 | 64(20–92) | I-IV | R-CHOP | 2000–2007 | 3.5 | OS, PFS |
| Ho | 2015 | Taiwan | 9 | 148 | 61(16–88) | I-IV | R-CHOP | 2001–2010 | 4.35 | OS, PFS |
| Keam | 2015 | Korea | 8 | 447 | 61(16–87) | I-IV | R-CHOP | 2003–2010 | 3 | OS, PFS |
| Melchardt | 2015 | Austria | 8 | 515 | 65(20–92) | I-IV | R-CHOP | 2004–2014 | 5.54 | OS |
| Ming | 2015 | China | 7 | 51 | 55(20–85) | I-IV | R-CHOP | 2009–2013 | 2.32 | OS |
| Hong | 2016 | Korea | 8 | 313 | 56(16–86) | I-IV | R-CHOP | 2008–2011 | 2.42 | PFS |
| Ni | 2016 | China | 7 | 57 | 54(14–75) | I-IV | R-CHOP | 2009–2015 | 2.915 | OS, PFS |
| Wang | 2016 | China | 8 | 156 | NR | I-IV | R-CHOP | 2006–2015 | 3 | OS, PFS |
| Wang | 2017 | China | 9 | 355 | 54(18–86) | I-IV | R-CHOP | 2005–2011 | 2.81 | OS, PFS |
OS = overall survival; PFS = progression-free survival; R-CHOP = rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone; NOS = Newcastle-Ottawa Scale, NR = not reported.