Table 1 Characteristics of included studies
Author | Year of Publication | Country | Group | No of patients | Tumor Location | Quality score |
|---|---|---|---|---|---|---|
Erturk | 2003 | Turkey | G-A G + S | 23 38 | Upper, Middle | 7 |
Ji | 2016 | China | G-A G + S | 243,105 | Upper | 8 |
Lee | 2001 | Korea | G-A G + S | 173,492 | Upper, Middle, Whole | 8 |
Kodera | 1997 | Japan | G-A G + S | 57,129 | Upper | 7 |
Ohkura | 2017 | Japan | G-A G + S | 45 63 | Upper | 7 |
Yao | 2011 | China | G-A G + S | 61 51 | Upper, Whole | 7 |
Fang | 2012 | Taiwan | G + SPSHD G + S | 68 47 | Upper | 7 |
Kwon | 1997 | Korea | G + SPSHD G + S | 232,260 | Upper, Middle, Whole | 8 |
Oh | 2009 | Korea | G + SPSHD G + S | 267 99 | Upper | 8 |
Son | 2017 | Korea | G + SPSHD G + S | 68 44 | Upper, Middle, Whole | 7 |