Sigmoidoscopy and faecal occult blood test - a comparative screening trial

Evaluating gut microbiota profiles from archived fecal samples

BACKGROUND

Associations between colorectal cancer and microbiota have been identified. Archived fecal samples might be valuable sample sources for investigating causality in carcinogenesis and biomarkers discovery due to the potential of performing longitudinal studies. However, the quality, quantity and stability of the gut microbiota in these fecal samples must be assessed prior to such studies. We evaluated i) cross-contamination during analysis for fecal blood and ii) evaporation in stored perforated fecal immunochemical tests (iFOBT) samples, iii) temperature stability as well as iv) comparison of the gut microbiota diversity and composition in archived, iFOBT and fresh fecal samples in order to assess feasibility of large scale microbiota studies.

METHODS

The microbiota profiles were obtained by sequencing the V3-V4 region of 16S rDNA gene.

RESULTS

The iFOBT does not introduce any cross-sample contamination detectable by qPCR. Neither could we detect evaporation during freeze-thaw cycle of perforated iFOBT samples. Our results confirm room temperature stability of the gut microbiome. Diverse microbial profiles were achieved in 100% of fresh, 81% of long-term archived and 96% of iFOBT samples. Microbial diversity and composition were comparable between fresh and iFOBT samples, however, diversity differed significantly between long-term archived, fresh and iFOBT samples.

CONCLUSION

Our data showed that it is feasible to exploit archived fecal sample sets originally collected for testing of fecal blood. The advantages of using these sample sets for microbial biomarker discovery and longitudinal observational studies are the availability of high-quality diagnostic and follow-up data. However, care must be taken when microbiota are profiled in long-term archived fecal samples.

Improving Cancer Preventive Behaviors: A Randomized Trial of Tailored Lifestyle Feedback in Colorectal Cancer Screening

BACKGROUND

Cancer screening provides an opportunity to increase awareness of cancer-preventive lifestyle behaviors such as nonsmoking, physical activity, low alcohol consumption, and a healthy diet. We tested the effect of standardized, individually tailored written feedback (TF), and a standard leaflet (SL) on 1-year lifestyle behaviors in a colorectal cancer screening setting.

METHODS

A total of 3,642 men and women aged 50-74 years invited to sigmoidoscopy screening were randomly assigned to: (i) TF; (ii) SL for cancer-preventive lifestyle behaviors; or (iii) control. Participants were mailed two self-reported lifestyle questionnaires (LSQ) 1 year apart. The TF intervention was based on the prescreening LSQ answers. We analyzed differences [with 95% confidence intervals (CI)] by comparing prescreening to 1-year follow-up of single cancer-preventive factors and the number of cancer-preventive lifestyle behaviors (range 0-4) between the groups by multivariable logistic regression and analysis of covariance (ANCOVA).

RESULTS

A total of 1,054 screening participants without neoplastic findings (29% of those invited to screening) were included in this study. Participants in the TF group increased their number of cancer-preventive lifestyle behaviors significantly compared with those in the control group by 0.11 (95% CI, 0.02 to 0.19). Overweight/obese individuals in the TF group had a -0.84 kg (95% CI, -1.47 to -0.22) larger reduction in body weight compared with the control group.

CONCLUSIONS

TF at sigmoidoscopy screening led to small improvements in cancer-preventive behaviors.

IMPACT

Colorectal cancer screening is a suitable setting for increasing awareness of cancer-preventive behavior.

Short-term survival after colorectal cancer in a screened versus unscreened population

Aims: United States' (US) colorectal cancer (CRC) screening and treatment practices seek to reduce mortality. We examined the survival of US patients compared with patients in the virtually unscreened Norwegian population. Methods: We compared short-term survival after CRC between the US and Norway using relative survival (RS) and excess mortality (EMR) analyses. The CRC patients were aged 50 and older diagnosed in the US (Surveillance, Epidemiology and End Results registry, 2004, N=9511) and in Norway (Cancer Registry of Norway, 2003-2005, N=8256). Results: Death occurred within three years for 39% of the CRC patients. Stage distributions were more favorable for US patients. Stage-specific survival was similar for localized and regional cancers, but more favorable for US distant cancers. In multivariate models of patient, tumor and treatment characteristics, patients (especially below age 80) in the US experienced longer survival (EMR 0.9, CI 0.8-0.9). Stage-specific analyses showed, however, that survival for localized cancers was relatively shorter in the US than in Norway (EMR 1.4, CI 1.1-1.8), but longer for distant cancers (EMR 0.8, CI 0.7-0.8). Conclusions: The enhanced survival for US CRC patients likely reflects a screening-related earlier diagnostic stage distribution, as well as prioritized life extension for patients with metastatic cancers, reflecting vastly different health care systems in the two countries. CRC screening is currently under consideration in Norway. For survival outcomes, the current findings do not discourage such an implementation. Other screening-related aspects such as feasibility and cost-benefit are, however, also relevant and warrant further research within a socialized health system.

Lifestyle predictors for non-participation and outcome in the second round of faecal immunochemical test in colorectal cancer screening

BACKGROUND

To reduce colorectal cancer (CRC) mortality through population-based screening programmes using faecal tests, it is important that individuals continue to participate in the repeated rounds of screening. We aimed to identify lifestyle predictors for discontinuation of faecal immunochemical test (FIT) screening after the first round, as well as lifestyle predictors for colorectal neoplasia detected in the second-round FIT screening.

METHODS

In this longitudinal study, we invited 6959 individuals aged 50-74 years from south-east Norway for a first round of FIT screening and to complete a self-reported lifestyle questionnaire on demographic factors, body mass index (BMI, kg m-2), smoking habits, physical activity, consumption of alcohol and dietary items. Two years later, we estimated the associations between these factors, non-participation and screening results in the second round of FIT screening using adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of the 3114 responders to the questionnaire who completed the first-round FIT and who were invited to participate in second-round FIT screening, 540 (17%) did not participate. The OR and (95% CI) for discontinuation of FIT screening after the first round was 1.61 (1.24-2.10) for current smoking compared with non-smoking; 2.01 (1.25-3.24) for BMI⩾35 kg m-2 compared with BMI 16.9-24.9 kg m-2 and 0.70 (0.52-0.94) for physical activity in the third quartile vs the first. Among participants, smoking, high BMI and high alcohol consumption were associated with an increased odds of detecting colorectal neoplasia (n=107).

CONCLUSIONS

These results may indicate that Norwegian FIT screening participants who discontinue after the first round have lifestyle behaviours associated with increased risk of CRC.