Postpolypectomy surveillance in patients with adenomas and serrated lesions: a proposal for risk stratification in the context of organized colorectal cancer-screening programs

Meta-Analysis and Validation of a Colorectal Cancer Risk Prediction Model Using Deep Sequenced Fecal Metagenomes

The gut microbiome is a potential modifiable risk factor for colorectal cancer (CRC). We re-analyzed all eight previously published stool sequencing data and conducted an MWAS meta-analysis. We used cross-validated LASSO predictive models to identify a microbiome signature for predicting the risk of CRC and precancerous lesions. These models were validated in a new study, Colorectal Cancer Screening (COLSCREEN), including 156 participants that were recruited in a CRC screening context. The MWAS meta-analysis identified 95 bacterial species that were statistically significantly associated with CRC (FDR < 0.05). The LASSO CRC predictive model obtained an area under the receiver operating characteristic curve (aROC) of 0.81 (95%CI: 0.78−0.83) and the validation in the COLSCREEN dataset was 0.75 (95%CI: 0.66−0.84). This model selected a total of 32 species. The aROC of this CRC-trained model to predict precancerous lesions was 0.52 (95%CI: 0.41−0.63). We have identified a signature of 32 bacterial species that have a good predictive accuracy to identify CRC but not precancerous lesions, suggesting that the identified microbes that were enriched or depleted in CRC are merely a consequence of the tumor. Further studies should focus on CRC as well as precancerous lesions with the intent to implement a microbiome signature in CRC screening programs.

Polygenic risk score across distinct colorectal cancer screening outcomes: from premalignant polyps to colorectal cancer

BACKGROUND

Different risk-based colorectal cancer (CRC) screening strategies, such as the use of polygenic risk scores (PRS), have been evaluated to improve effectiveness of these programs. However, few studies have previously assessed its usefulness in a fecal immunochemical test (FIT)-based screening study.

METHODS

A PRS of 133 single nucleotide polymorphisms was assessed for 3619 participants: population controls, screening controls, low-risk lesions (LRL), intermediate-risk (IRL), high-risk (HRL), CRC screening program cases, and clinically diagnosed CRC cases. The PRS was compared between the subset of cases (n = 648; IRL+HRL+CRC) and controls (n = 956; controls+LRL) recruited within a FIT-based screening program. Positive predictive values (PPV), negative predictive values (NPV), and the area under the receiver operating characteristic curve (aROC) were estimated using cross-validation.

RESULTS

The overall PRS range was 110-156. PRS values increased along the CRC tumorigenesis pathway (Mann-Kendall P value 0.007). Within the screening subset, the PRS ranged 110-151 and was associated with higher risk-lesions and CRC risk (OR_D10vsD1 1.92, 95% CI 1.22-3.03). The cross-validated aROC of the PRS for cases and controls was 0.56 (95% CI 0.53-0.59). Discrimination was equal when restricted to positive FIT (aROC 0.56), but lower among negative FIT (aROC 0.55). The overall PPV among positive FIT was 0.48. PPV were dependent on the number of risk alleles for positive FIT (PPVp10-p90 0.48-0.57).

CONCLUSIONS

PRS plays an important role along the CRC tumorigenesis pathway; however, in practice, its utility to stratify the general population or as a second test after a FIT positive result is still doubtful. Currently, PRS is not able to safely stratify the general population since the improvement on PPV values is scarce.

Impact of a Primary Care intervention on the colorectal cancer early detection programme

AIM

To assess the effectiveness of a telephonic interview performed by primary care professionals among non-participants in the first round of the colorectal cancer early detection programme in the basic urban health area Guineueta in Barcelona, Spain.

PATIENTS AND METHODS

The Primary Healthcare Team of La Guineueta contacted people who did not respond to the invitation to the first round of the colorectal cancer early detection programme using a standardised telephone call protocol. We analysed the impact of the intervention based on participation and diagnosed disease.

RESULTS

We made 3,327 phone calls to 2,343 people. After the intervention the participation rate was 54.9%, which meant an increase of 5.7% with respect to the participation in the usual protocol for the programme (49.2%). The intervention allowed 5cancers, 2high-risk neoplasms and 8low- and intermediate-risk lesions to be diagnosed. An average of 9phone calls was necessary to achieve the participation of one additional person.

DISCUSSION

The telephonic intervention performed by primary care professionals has significantly increased the population participation rate and the detection of neoplasms with respect to the usual colorectal cancer early detection programme protocol.

Advanced Hepatic Fibrosis in Fatty Liver Disease Linked to Hyperplastic Colonic Polyp

Aim. Our study aims to determine possible association between biopsy-proven nonalcoholic steatohepatitis (NASH) and hyperplastic polyps (HP) of the colon. Methods. A retrospective cohort observational study. All subjects underwent screening colonoscopy within two years. Data were extracted from the patient charts including demographic, anthropometric measurement, vital signs, underlying diseases, medical therapy, laboratory data, results of the liver biopsy with degree of fibrosis and necroinflammatory activity, the colonoscopy report, and the pathological report of the extracted polyp. Results. A total of 223 patients were included in our study, 123 patients with biopsy-proven NASH and 100 patients without NASH who served as the control group matched for age. 14 colonic adenomas (11% of patients) were found in the NASH group compared with 16 adenomas (16% of patients) found in the control group (P = 0.9). 28 HPs were found in the NASH group (22.7%) compared with only 8 HPs in the control group (8%) (P < 0.05). 21 from the 28 (75%) HPs diagnosed in the NASH group were observed in the high degree fibrosis patients (Fibrosis Stages 3 and 4), 6 HPs (21%) were associated with Fibrosis Stages 1 and 2, and single HP (4%) was associated with Fibrosis Stage 0. Conclusions. Our study showed an association between biopsy-proven steatohepatitis and the burden of hyperplastic polyp. The severity of hepatic fibrosis may play important role in the increased occurrence of HPs.

Choosing the optimal method in programmatic colorectal cancer screening: current evidence and controversies

Colorectal cancer (CRC) is an important health problem all over the world, being the third most common cancer and the second leading cause of cancer-related death in Western countries. The most important strategy for CRC prevention is screening (i.e. secondary prevention). Since it is widely accepted that adenomas and serrated polyps are the precursors of the vast majority of CRC, early detection and removal of these lesions is associated with a reduction of CRC incidence and, consequently, mortality. Moreover, cancers detected by screening are usually diagnosed at early stages and, therefore, curable by endoscopic or surgical procedures. This review will be address CRC screening strategies in average-risk population, which is defined by those individuals, men and women, 50 years of age or older, without any additional personal or familial predisposing risk factor. In order to maximize the impact of screening and ensure high coverage and equity of access, only organized screening programs (i.e. programmatic screening) should be implemented, as opposed to case-finding or opportunistic screening. For that reason and considering that the optimal approach for colorectal screening may differ depending on the scenario, this review will be focused on the advantages and limitations of each screening strategy in an organized setting.