Current focus in colorectal cancer management is on reducing overall colorectal cancer mortality by increasing the number of early stage cancers diagnosed and treated with curative intent. There is good evidence that screening for colorectal cancer increases the number of early-stage cancers diagnosed and leads to a reduction of cancer specific mortality. Despite the success of the colorectal cancer screening programme in down-staging colorectal cancer, interval cancer rates are substantial and other strategies to reduce colorectal cancer risk and disease recurrence after surgery with curative intent are desirable.

Aim: Although the relationship between colorectal neoplasia and inflammation is well described, the role of faecal calprotectin (FC) in clinical practice to diagnose or screen patients for colorectal neoplasia is less defined. This prospective study characterizes the relationship between FC and colorectal neoplasia in patients within the faecal occult blood testing (FOBT) positive patients in the Scottish Bowel Screening Programme.Methods: All FOBT positive patients attending for colonoscopy between February 2016 and July 2017 were invited to participate. Patients provided a stool sample for FC before commencing bowel preparation. All demographics and endoscopic findings were collected prospectively.Results: In all, 352 patients were included. 210 patients had FC > 50 µg. Colorectal cancer (CRC) patients had a higher median FC (138.5 μg/g, P < 0.05), in comparison to those without CRC, and 13/14 had an FC > 50 µg/g (93%). FC had a high sensitivity (92.8%) and negative predictive value (99.3%) for CRC, but with a low specificity (41.7%) and positive predictive value (6.2%). FC sensitivity increased sequentially as neoplasms progressed from non-advanced to malignant neoplasia (48.6% non-advanced adenoma vs. 92.9% CRC). However, no significant relationship was observed between FC and non-cancer neoplasia. Conclusion:In an FOBT positive screening population, FC was strongly associated with CRC (sensitivity 92.8%, specificity 41.7% for CRC, at 50 µg/g). However, although sensitive for the detection of CRC, FC failed to show sufficient sensitivity or specificity for the detection of non-cancer neoplasia. Based on these results we cannot recommend routine use of FC in a bowel screening population to detect cancer per se, but it is apparent that, with further optimization, faecal assessments including quantification of haemoglobin and inflammation could form part of a risk assessment tool aimed at refining the selection of patients for colonoscopy in both symptomatic and screening populations.

Polyphenols may inhibit carcinogenesis through their antioxidant and anti-inflammatory properties.(1) While their efficacy has been explored in vitro, clinical evidence of their impact on human health is lacking. This study aims to systematically review case-controlled studies examining dietary intake of polyphenols and the development colorectal cancer (CRC).MEDLINE, EMBASE, Web of Science, CABI, BIOSIS, CINAHL, DARE, TRIP & CDSR were searched using a predefined search strategy including 52 polyphenolic compounds. The primary outcome was diagnosis of CRC. Case-control studies measuring polyphenol intake in humans published in English between 1990-2012 were included. Study quality was assessed by the Newcastle-Ottawa Scale (NOS). Meta-analysis of adjusted odds ratios (OR) was performed with RevMan5.2. Heterogeneity was assessed using I 2 statistics. 6411 articles were identified and 7 studies met inclusion criteria (Table 1). These studies had a combined total of 18,071 patients, consisting of 6965 cases and 11106 controls. All studies were of moderate to good quality (NOS range 5-8/9). Based on self reported food-frequency questionnaires (FFQs), a total of 20 polyphenol measurements were assessed.Based on single reports, consumption of anthocyanidins, catechin, epicatechin, enterolignans and enterolactone were associated with a reduced CRC risk. Pooled analysis showed intake of flavonols and procyanidins was associated with a reduced risk (OR:0.70 95% CI:0.61-0.80 and OR:0.78 95% CI:0.65-0.94 respectively). Non-significant trends were demonstrated with intake of phytoeostrogens (pooled OR:0.87 95% CI:0.65-1.18), quercetin (pooled OR:0.82 95% CI:0.60-1.12) and total isoflavones consumption (pooled OR:0.84 95% CI:0.66-1.06) however statistical heterogeneity was high (I 2 > 70%) with one study* skewing results significantly. No other polyphenols showed significant associations.In conclusion, results from case-controlled studies suggest that dietary consumption of some polyphenol sub-groups are associated with a reduced risk of developing CRC. However these associations are not as strong as in vitro studies would suggest. Differences in quantification of polyphenol consumption within the reported literature may hide the true role that other polyphenols play in CRC prevention. Different FFQs were used between studies and most were not validated to assess polyphenol consumption. Future epidemiological studies may consider utilising objective biomarkers as proxy measures of polyphenol intake to negate uncertainty in polyphenol intake measurements based on patient reported FFQs.