Table 1.
Baseline characteristics of studies determining the mucosal colorectal microbiota of CRC patients and healthy controls.
| First Author, Year | Country | No. Participants | Study Participants (Males) Age Mean or Median ± SD (Range) |
Recruitment | Exclusions | |
|---|---|---|---|---|---|---|
| CRC | Healthy Controls | |||||
| Geng, 2014 [33] | China | 18 | 8 (4) Mean 56.9 ± 14.4 |
10 (NR) NR |
CRC: Undergoing colonoscopy HC: volunteers |
NR |
| Gao, 2015 [58] | China | 61 | 31 (15) Mean 67 ± 7.2 |
30 (14) Mean 70 ± 5.1 |
CRC: Undergoing CRC surgery HC: Undergoing colonoscopy |
HC: BMI > 30 kg/m2; HC and CRC: use of antibiotics within 2 months, regular use of NSAIDs, statins, or probiotics; chronic bowel disorders, food allergies/dietary restrictions; pre-operative radiation or chemotherapy |
| Mira-Pascual, 2015 [34] | Spain | 12 | 7 (7) Mean 71.1 ± 10.1 |
5 (3) Mean 58.8 ± 10 |
Undergoing CRC screening | NR |
| Nakatsu, 2015 [59] | China | DC: 113 VC: 75 |
DC: 52 (31) Mean 67.85 ± 13.18 VC: 50 (26) Mean 61.34 ± 9.97 |
DC: 61 (25) Mean 60.813 ± 5.99 VC: 25 (10) Mean 41.28 ± 7.87 |
Undergoing CRC screening | Personal history of CRC, IBD, prosthetic heart valve or vascular graft surgery; contraindications for colonoscopy |
| Thomas, 2016 [35] | Brazil | 36 | 18 (10) Mean 59.3 ± 8.8 |
18 (9) Mean 55.2 ±15.7 |
HC: Undergoing exploratory colonoscopy CRC: Undergoing CRC surgery |
HC and CRC: use of antibiotics 4 weeks before sample collection; CRC: neoadjuvant therapy prior to tissue collection; IBD, hereditary cancer syndromes |
| Flemer, 2017 [57] | Ireland | 115 | 59 (37) Range 41–90 |
56 (24) Range 27–29 |
HC: Undergoing s colonoscopy CRC: Undergoing CRC surgery |
HC and CRC: Personal history of CRC, IBD, or IBS; CRC: use of antibiotics the month prior to surgery |
| Richard, 2018 [60] | Italy | 27 | CAC: 7(5) Mean 50.7 ± 10 SC: 10 (5) Mean 68.8 ± 12.1 |
10 (7) Mean 48.3 ± 13.4 |
HC: Undergoing routine screening CRC: Undergoing CRC surgery |
HC: History/clinical symptoms of intestinal disorders and endoscopic/histological signs of cancer or IBD; HC and CRC: Infectious colitis, coagulation disorders, anticoagulant therapy; use of antibiotics/antifungal therapy 2 months before inclusion |
| Zhang, 2019 [36] | China | 23 | 9 (6) Mean 62.6 ± 8.9 |
14 (7) Mean 44.1 ± 15 |
Undergoing CRC screening | IBS; use of antibiotics or probiotics 30 days or infectious gastroenteritis 60 days before colonoscopy |
| Wang Y, 2020 [61] | China | 101 | 75 (48) Mean 63.4 (Range 29–82) |
26 (17) Mean 51.7 (Range 21–71) |
HC: Undergoing colonoscopy CRC: Undergoing CRC surgery |
NR |
| Nardelli, 2021 [65] | Italy | 40 | 20 (10) Mean 69.4 |
20 (10) Mean 53.2 |
HC: Undergoing colonoscopy CRC: Undergoing CRC surgery |
IBD or IBS; use of antibiotics, pro/prebiotics, antiviral, or corticosteroids 2 months prior to sample collection |
| Osman, 2021 [68] | Malaysia | 36 | 18 (12) Mean 64.88 ± 2.34 |
18 (11) Mean 54.44 ± 2.91 |
Undergoing colonoscopy and tumor removal surgery | History of cancer, IBD and polyps; use of antibiotics 3 months prior to radiotherapy or chemotherapy prior to surgery |
| Wang, 2021 [69] | China | 60 | 30 (17) Mean 63.9 ± 6.58 |
30 (15) Mean 52.17 ±9.02 |
HC: Undergoing colonoscopy CRC: Undergoing surgery |
History of cancer, Peutz–Jeghers or Lynch syndromes; use of antibiotics/NSAIDS 1 month prior to sample collection |
Abbreviations: CAC: colitis-associated colorectal cancer; CRC: colorectal cancer; DC: discovery cohort; HC: healthy controls; IBD: inflammatory bowel disease; IBS: irritable bowel syndrome; NR: not reported; NSAIDs: non-steroidal anti-inflammatory drugs; SC: sporadic colorectal cancer; SD: standard deviation; VC: validation cohort.