Lifestyle in patients at increased risk of colorectal cancer

Changes in Lifestyle Factors After Endoscopic Screening: A Prospective Study in the United States

BACKGROUND

Endoscopic screening and adherence to a healthy lifestyle are major avenues for colorectal cancer (CRC) prevention. We investigated changes in lifestyles after endoscopic screening.

METHODS

We drew data from 76,303 pairs of time- and age-matched individuals who had and had not, respectively, reported first time endoscopic screening, in the 3 cohorts (Nurses' Health Study I and II and the Health Professionals Follow-up Study). Detailed information was collected every 2-4 years on endoscopy screening, 12 lifestyle factors (including smoking, physical activity, regular use of aspirin/nonsteroidal anti-inflammatory drugs, body weight, and 8 dietary factors), and adherence to a healthy lifestyle based on a score defined by 5 major lifestyle factors (smoking, alcohol, body weight, physical activity, and diet). We assessed changes in lifestyle from pre- to post-screening periods for the matched pairs. We also conducted subgroup analysis according to screening findings (negative, low- and high-risk polyps, and CRC).

RESULTS

Endoscopic screening was associated with higher prevalence of adherence to a healthy lifestyle (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.04-1.16). The association strengthened with the severity of the screening findings, with an OR of 1.09 (95% CI, 1.03-1.15) for negative screening, 1.19 (95% CI, 1.07-1.33) for low-risk polyps, 1.42 (95% CI, 1.14-1.77) for high-risk polyps, and 1.55 (95% CI, 1.17-2.05) for CRC. The individual lifestyle factors and diet showed modest change.

CONCLUSIONS

Endoscopic screening was associated with a modest improvement in healthy lifestyles, particularly in individuals with more severe endoscopic findings. Further efforts of integrating lifestyle medicine into the screening setting are needed, to better leverage the teachable moment in improving CRC prevention.

Screening Colonoscopy Findings Are Associated With Noncolorectal Cancer Mortality

INTRODUCTION

Controversy exists regarding the impact of various risk factors on noncolorectal cancer (CRC) mortality in healthy screening populations. We examined the impact of known CRC risk factors, including baseline colonoscopy findings, on non-CRC mortality in a screening population.

METHODS

Cooperative Studies Program (CSP) #380 is comprised of 3,121 veterans aged 50-75 years who underwent screening colonoscopy from 1994 to 97 and were then followed for at least 10 years or until death. Hazard ratios (HRs) for risk factors on non-CRC mortality were estimated by multivariate Cox proportional hazards.

RESULTS

Current smoking (HR 2.12, 95% confidence interval [CI] 1.78-2.52, compared with nonsmokers) and physical activity (HR 0.89, 95% CI 0.84-0.93) were the modifiable factors most associated with non-CRC mortality in CSP#380. In addition, compared with no neoplasia at baseline colonoscopy, non-CRC mortality was higher in participants with ≥3 small adenomas (HR 1.43, 95% CI 1.06-1.94), advanced adenomas (HR 1.32, 95% CI 0.99-1.75), and CRC (HR 2.95, 95% CI 0.98-8.85). Those with 1-2 small adenomas were not at increased risk for non-CRC mortality (HR 1.15, 95% CI 0.94-1.4).

DISCUSSION

In a CRC screening population, known modifiable risk factors were significantly associated with 10-year non-CRC mortality. Furthermore, those who died from non-CRC causes within 10 years were more likely to have had high-risk findings at baseline colonoscopy. These results suggest that advanced colonoscopy findings may be a risk marker of poor health outcomes. Integrated efforts are needed to motivate healthy lifestyle changes during CRC screening, particularly in those with high-risk colonoscopy findings and unaddressed risk factors.

Nutritional prevention of colorectal cancer

The preventability estimate for colorectal cancer (CRC) is approximately 50%, highlighting the huge potential for altering modifiable lifestyle factors (including diet and body fatness) in order to reduce risk of this common malignancy. There is strong evidence that dietary factors (including intake of wholegrains, fibre, red and processed meat and alcohol) affect CRC risk. The lack of positive intervention trials and limited mechanistic understanding likely explain limited public health impact of epidemiological observations, to date. An alternative strategy for nutritional prevention of CRC is use of supplements that provide higher individual nutrient exposure than obtained through the diet (chemoprevention). There are positive data for calcium and/or vitamin D and the n-3 fatty acid EPA from polyp prevention trials using colorectal adenoma as a CRC risk biomarker. Although CRC is an obesity-related malignancy, there remains a paucity of observational data supporting intentional weight loss for CRC risk reduction. Some types of obesity surgeries (Roux-en-Y gastric bypass) might actually increase subsequent CRC risk due to alteration of local intestinal factors. There is intense interest in nutritional therapy of patients after diagnosis of CRC, in order to impact on recurrence and overall survival (now often termed cancer interception). In conclusion, nutritional prevention of CRC continues to hold much promise. Increased mechanistic understanding of the role of individual nutrients (linked to intestinal microbiota), as well as a precision medicine approach to CRC chemoprevention and interception based on both tumour and host factors, should enable translation of nutritional interventions into effective CRC risk reduction measures.

Ethanol promotes alcohol-related colorectal cancer metastasis via the TGF-β/RUNX3/Snail axis by inducing TGF-β1 upregulation and RUNX3 cytoplasmic mislocalization

BACKGROUND

Alcohol intake is a well-known lifestyle risk factor for CRC, and an increasing number of studies have revealed that alcohol intake is also tightly associated with CRC metastasis. However, the effect of alcohol on CRC metastasis and its underlying mechanism remain unclear.

METHODS

A retrospective cohort study was performed to investigate the characteristics of patients with alcohol-related CRC. The effects of ethanol on the biological behaviours of CRC cells were assessed through in vivo and in vitro assays using the Lieber-DeCarli ethanol liquid diet and ethanol, respectively. The ethanol-mediated signalling pathway and downstream factors were screened through ELISA, western blot, immunofluorescence and co-immunoprecipitation.

FINDINGS

Most patients with alcohol-related CRC, particularly those with tumour metastasis, were characterized by a notably higher circulating ethanol level and a lower systemic acetaldehyde level. Moreover, CRC cells accumulated in ethanol, but not acetaldehyde, to notably higher levels compared with adjacent normal cells. Alcohol intake significantly promoted CRC metastasis via the ethanol-mediated TGF-β/Smad/Snail axis, and ethanol induced the cytoplasmic mislocalization of RUNX3 and further promoted the aggressiveness of CRC by targeting Snail. Pirfenidone (PFD) significantly eliminated the effects of ethanol on CRC metastasis by specifically blocking TGF-β signalling.

INTERPRETATION

Alcohol intake plays a vital role in CRC metastasis via the ethanol-mediated TGF-β/RUNX3/Snail axis, and PFD might be a novel therapeutic management strategy for CRC.