“…For the subgroup analysis, conventional cytology studies 2,3,10,11,15,16,18,19,22,25,29,34,40,41,43,46,48-57,60,63,69,70,78,81,83,87,92,94,96,99,101 (risk difference: 0.39; 95% CI: 0.35–0.43; n=2,374 patients; I 2 =93%; p <0.00001) and PCR-CEA 28,36-38,48-51,57,58,64,70,76,77,83,89,93,94,97,101, (risk difference: 0.51; 95% CI: 0.45–0.57; n=2,612 patients; I 2 =66%; p <0.00001) were reviewed.…”