Table 2 Characteristics of studies included in the systematic review
First author (year) | Country | Study design | No. of CRC /C | Age, mean (SD) | Exclusion of subjects with history of antibiotic use (period) | Exclusion of subjects with history of IBD diagnosis | Specimen type | Specimen collection time | Detection method | Study quality based on NOS scores | |
|---|---|---|---|---|---|---|---|---|---|---|---|
CRC | C | ||||||||||
Amitay (2017) [40] | Germany | NCC | 46/231 | 66.9 (-) | 62.1 (-) | No | Yes | Feces | Before colonoscopy | 16S rRNA gene analysis | Poor |
Yu (2015) [41] | China | CC | 42/52 | --- | --- | Yes (last 6 months) | Yes | Feces and biopsy c | Feces: non-reported Biopsies: left tissues | 454 FLX pyrosequencing and PCR | Poor |
Zhang (2018) [42] | China | CC | 130/130 | 60.5 (9.8) | 58.6 (8.9) | Yes (last 6 months) | Yes | Feces | Before colonoscopy | 16S rDNA sequencing and PCR | Good |
Flanagan (2014) [43] | Ireland | CC | 7/25 | --- | --- | No | Yes | Feces | --- | qPCR | Poor |
Fukugaiti (2015) [44] | Brazil | CC | 7/10 | 65.4 (1.1) | 54.8 (1.3) | Yes (unspecified) | No | Feces | Before colonoscopy | qPCR | Poor |
Suehiro (2017) [45] | Japan | CC | 158/60 | 69 (-) | 32 (-) | No | No | Feces | Prior to bowel preparation | dd-PCR | Poor |
Rezasoltani (2018) [46] | Iran | CC | 20/31 | 60.9 (13.5) | 59.8 (17) | Yes (last 6 months) | Yes | Feces | Before colonoscopy | qPCR | Poor |
Eklof (2017) [47] | Sweden | NCC | 39/65 | 34 (-) | 34 (-) | No | Yes (for C only) | Feces | Prior to bowel preparation | qPCR | Good |
Guo (2018) [48] | China | CC | 215/156 | --- | --- | Yes (last 3 months) | Yes | Feces | Time of diagnosis, before resection | qPCR | Poor |
Liang (2017) [49] | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Cohort I | China | CC | 170/200 | 67.2 (11.6) | 59.3 (5.8) | Yes (last 3 months) | No | Feces | Before or one month after colonoscopy | qPCR | Good |
 Cohort II | China | 33/36 | 63.4 (9.6) | 53.2 (12.2) | |||||||
Mira-Pascual (2015) [50] | Spain | CC | 7/9 | 71.1 (10.1) | 52.6 (15.2) | No | No | Feces and biopsyd | ≥ 1 week before colonoscopy | qPCR | Good |
Repass (2018) [51] | USA | CC | 40/40 | --- | --- | No | No | Biopsy | During surgery | qPCR | Fair |
Russo (2017) [52] | Italy | CC | 10/10 | --- | --- | Yes (last 3 months) | No | Feces | 1 day before surgery for CRC and unspecified for C | qPCR | Poor |
Vogtmann (2016) [53] | USA | CC | 52/52 | 61.8 (-) | 61.2 (-) | No | No | Feces | Prior to surgery or other treatment | WGSS | Good |
Wang (2016) [54] | China | CC | 10/10 | 54.8 (-) | 54 (-) | No | No | Feces | --- | PCR | Good |
Wang (2012) [55] | China | CC | 46/56 | 60a | 49a | Yes (last 3 months) | Yes (for C only) | Feces | Before surgery for CRC patients and unspecified for C | qPCR | Poor |
Wong (2017) [56] | China | CC | 104/102 | 66.9 (10.1) | 57.1 (5.8) | Yes (last 3 months) | Yes | Feces | Prior to bowel preparation for colonoscopy | qPCR | Poor |
Wu (2013) [57] | China | CC | 19/20 | 58.3 (8.7) | 53.2 (5.4) | Yes (last 3 months) | Yes (for C only) | Feces | --- | qPCR | Good |
Xie (2017) [58] | China | CC | 327/242 | 63.5 (10.2) | 60.1 (8.4) | Yes (last month) | Nob | Feces | Prior to bowel preparation for surgery or endoscopy | qPCR | Good |
Yu (2016) [59] | China | CC | 93/20 | 59.25(-) | --- | No | No | Biopsy | Colonoscopy or surgery | FISH | Poor |
Yu (2017) [60] | China | CC | 74/54 | 63 (50.7) | 67 (34.9) | Yes (last 3 months) | Yes | Feces | Before or mostly after colonoscopy | Metagenomic sequencing | Poor |
Tunsjo (2019) [61] | Norway | CC | 23/22 | 70 (-) | 57 (-) | No | No | Feces and biopsy e | Prior to bowel preparation or 1 week after colonoscopy | qPCR | Poor |
Liu (2020) [62] | China | CC | 53/45 | 52.4 (18.8) | 53.7 (16.7) | Yes (last month) | Yes | Feces | Prior to bowel preparation for colonoscopy | qPCR | Good |
Kashani (2020) [63] | Iran | CS | 35/45 | --- | --- | No | No | Biopsy | Colonoscopy | PCR | Satisfactoryf |