Table 2 Summary of evidence credibility assessment of 17 unique meta-analyses of observational studies investigating the associations between risk factors and CRC recurrence
Population | Outcome | Risk factor | Risk factor prevalence | Effect size (95% CI) | Evidence classification |
|---|---|---|---|---|---|
Histopathological risk factor | |||||
 CRC | Overall recurrence in CRC | Tumor budding | 802/2773 = 29% | 5.50 (3.65–8.29) | Highly suggestive |
 CRC | Overall recurrence in CRC | Extranodal extension (ENE) | 376/877 = 43% | 2.07 (1.65–2.61) | Highly suggestive |
 Rectal cancer | Local recurrence in rectal cancer | Perineural invasion (PNI) | 336/1700 = 20% | 3.21 (2.33–4.44) | Highly suggestive |
 Rectal cancer | Distant metastatic recurrence in rectal cancer | MRI-detected extramural vascular invasion (mrEMVI) | 350/1262 = 28% | 3.91 (2.61–5.86) | Highly suggestive |
 CRC | Local recurrence in CRC | Intramural vascular invasion (IMVI) | 137/503 = 27% | 1.55 (0.11–21.28) | No association |
Biomarker | |||||
 CRC | Overall recurrence in CRC | Absence of peritoneal free tumor cells in pre-resection | 524/593 = 88% | 0.38 (0.16–0.91) | Weak |
 CRC | Overall recurrence in CRC | Absence of peritoneal free tumor cells in post-resection | 214/252 = 85% | 0.07 (0.02–0.21) | Weak |
Genetic risk factor | |||||
 CRC | Overall recurrence in CRC | PTGS2 (also known as COX-2) | 787/1516 = 52% | 2.78 (1.76–4.40) | Suggestive |
Clinical risk factor | |||||
 CRC | Local recurrence in CRC | Anastomotic leakage (AL) | 3929/39,745 = 10% | 1.90 (1.48–2.43) | Suggestive |
 Rectal cancer | Local recurrence in rectal cancer | Anastomotic leakage (AL) | 1300/13,665 = 10% | 1.61 (1.25–2.08) | Suggestive |
 CRC | Distant recurrence in CRC | Anastomotic leakage (AL) | 865/10,392 = 8% | 1.20 (0.94–1.52) | No association |
 Rectal cancer | Distant recurrence in rectal cancer | Anastomotic leakage (AL) | 566/5221 = 11% | 1.06 (0.72–1.58) | No association |
 Colon cancer | Local recurrence in colon cancer | Anastomotic leakage (AL) | 91/1990 = 5% | 2.19 (0.55–8.68) | No association |
Comorbidity | |||||
 CRC | Overall recurrence in CRC | Diabetes | 429/4979 = 9% | 1.26 (0.70–2.30) | No association |
Anthropometric indices | |||||
 CRC | Overall recurrence in CRC | Underweight | 2752/17,636 = 16% | 1.13 (1.05–1.21) | Weak |
 CRC | Overall recurrence in CRC | Obese | 6362/21,246 = 30% | 1.07 (1.02–1.13) | Weak |
 CRC | Overall recurrence in CRC | Overweight | 13,225/28,109 = 47% | 1.00 (0.96–1.05) | No association |