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Background: Dietary fiber has been associated with a reduced risk of colorectal cancer. However, it remains unclear at which stage in the carcinogenic pathway fiber may act or which food sources of dietary fiber may be most beneficial against colorectal cancer development. Objective: The objective was to prospectively evaluate the association between dietary fiber intake and the risk of incident and recurrent colorectal adenoma and incident colorectal cancer. Design: Study participants were identified from the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Participants received flexible sigmoidoscopy at baseline and 3 or 5 y after. Dietary fiber intake was measured by using a self-reported dietary questionnaire. The colorectal cancer, incident adenoma, and recurrent adenoma analyses were based on 57,774, 16,980, and 1667 participants, respectively. Unconditional logistic regression was used to assess the risk of incident and recurrent adenoma, and Cox proportional hazards models were used to assess the risk of colorectal cancer across categories of dietary fiber intake, with adjustment for potential confounders. Results: Elevated total dietary fiber intake was associated with a significantly reduced risk of incident distal colorectal adenoma (OR highest vs. lowest tertile of intake : 0.76; 95% CI: 0.63, 0.91; P-trend = 0.003) but not recurrent adenoma (P-trend = 0.67). Although the association was not statistically significant for colorectal cancer overall (HR: 0.85; 95% CI: 0.70, 1.03; P-trend = 0.10), a reduced risk of distal colon cancer was observed with increased total fiber intake (HR: 0.62; 95% CI: 0.41, 0.94; P-trend = 0.03). Protective associations were most notable for fiber originating from cereals or fruit. Conclusions: This large, prospective study within a population-based screening trial suggests that individuals consuming the highest intakes of dietary fiber have reduced risks of incident colorectal adenoma and distal colon cancer and that this effect of dietary fiber, particularly from cereals and fruit, may begin early in colorectal carcinogenesis. This trial was registered at clinicaltrials.gov as NCT01696981.Am J Clin Nutr 2015;102:881-90.

BackgroundWhile current research is largely consistent as to the harms of heavy drinking in terms of both cancer incidence and mortality, there are disparate messages regarding the safety of light-moderate alcohol consumption, which may confuse public health messages. We aimed to evaluate the association between average lifetime alcohol intakes and risk of both cancer incidence and mortality.Methods and findingsWe report a population-based cohort study using data from 99,654 adults (68.7% female), aged 55–74 years, participating in the U.S. Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Cox proportional hazards models assessed the risk of overall and cause-specific mortality, cancer incidence (excluding nonmelanoma skin cancer), and combined risk of cancer and death across categories of self-reported average lifetime alcohol intakes, with adjustment for potential confounders. During 836,740 person-years of follow-up (median 8.9 years), 9,599 deaths and 12,763 primary cancers occurred. Positive linear associations were observed between lifetime alcohol consumption and cancer-related mortality and total cancer incidence. J-shaped associations were observed between average lifetime alcohol consumption and overall mortality, cardiovascular-related mortality, and combined risk of death or cancer. In comparison to lifetime light alcohol drinkers (1–3 drinks per week), lifetime never or infrequent drinkers (<1 drink/week), as well as heavy (2–<3 drinks/day) and very heavy drinkers (3+ drinks/day) had increased overall mortality and combined risk of cancer or death. Corresponding hazard ratios (HRs) and 95% confidence intervals (CIs) for combined risk of cancer or death, respectively, were 1.09 (1.01–1.13) for never drinkers, 1.08 (1.03–1.13) for infrequent drinkers, 1.10 (1.02–1.18) for heavy drinkers, and 1.21 (1.13–1.30) for very heavy drinkers. This analysis is limited to older adults, and residual confounding by socioeconomic factors is possible.ConclusionsThe study supports a J-shaped association between alcohol and mortality in older adults, which remains after adjustment for cancer risk. The results indicate that intakes below 1 drink per day were associated with the lowest risk of death.Trial registrationNCT00339495 (ClinicalTrials.gov).

Background: The gut microbiome, in particular Fusobacterium nucleatum, has been reported to play a role in colorectal cancer development and in patient prognosis. We aimed to perform a systematic review and meta-analysis of published studies to assess the prevalence of F. nucleatum in colorectal tumors and evaluate the association between F. nucleatum and colorectal cancer development and prognosis.Methods: MEDLINE, EMBASE, and Web of Science databases were systematically searched for studies published until January 2019. Random effects meta-analyses were used to assess the prevalence of F. nucleatum in patients with colorectal cancer or tissues relative to controls and survival in F. nucleatum-positive versus -negative patients.Results: Forty-five relevant articles were identified. Meta-analyses indicated higher odds of F. nucleatum being present in colorectal tissue samples from patients with colorectal cancer [n ¼ 6 studies, pooled OR ¼ 10.06; 95% confidence intervals (CI), 4.48-22.58] and individuals with colorectal polyps (n ¼ 5 studies, pooled OR ¼ 1.83; 95% CI, 1.07-3.16) compared with healthy controls. Similar results were apparent in fecal samples, and when comparing tumor with adjacent normal tissue. Meta-analyses indicated poorer survival in patients with colorectal cancer with high versus low F. nucleatum abundance (n ¼ 5 studies, pooled HR ¼ 1.87; 95% CI, 1.12-3.11).Conclusions: A consistent increase in the prevalence and/or abundance of F. nucleatum in colorectal cancer tissue and fecal samples compared with controls was apparent. High abundance of F. nucleatum in colorectal tumors was also associated with poorer overall survival.Impact: F. nucleatum could be useful as a diagnostic and prognostic marker for colorectal cancer or as a treatment target. Materials and Methods Data sourcesAn a priori systematic search of the literature was performed in accordance with PRISMA guidelines (Supplementary Table S1; ref. 14

Background: Studies have examined whether tumor expression of PTGS2 (also known as COX-2), an enzyme inhibited by nonsteroidal anti-inflammatory drugs such as aspirin, is associated with prognosis in patients with colorectal cancer. However, results to date have been mixed.Methods: Using terms for PTGS2 and colorectal cancer, the Medline, Embase, and Web of Science databases were systematically searched for studies published, in any language, until December 2011. Random effects meta-analyses were used to calculate pooled HRs [95% confidence intervals (CI)] for the association between PTGS2 expression and tumor recurrence, colorectal cancer-specific survival, and overall survival.Results: In total, 29 studies, which had prognostic data on 5,648 patients, met the inclusion criteria. PTGS2-positive patients were at an increased risk of tumor recurrence (n ¼ 9 studies; HR, 2.79; 95% CI, 1.76-4.41; P < 0.001) and had poorer colorectal cancer-specific survival (n ¼ 7; HR, 1.36; 95% CI, 1.02-1.82; P ¼ 0.04). However, there was funnel plot asymmetry, possibly due to publication bias, for the association with cancerspecific survival but less so for recurrence. PTGS2 expression was not associated with overall survival [(n ¼ 16; pooled unadjusted HR, 1.30; 95% CI, 0.94-1.79; P ¼ 0.11) and (n ¼ 9; pooled adjusted HR, 1.02; 95% CI, 0.72-1.45;Conclusions: PTGS2 expression was associated with an increased risk of tumor recurrence and poorer colorectal cancer-specific survival but not overall survival among patients with colorectal cancer. However, confounding by tumor characteristics such as tumor stage seems likely.Impact: There is insufficient evidence to recommend PTGS2 expression as a prognostic marker in patients with colorectal cancer. Furthermore, studies providing adjusted results are required. Cancer Epidemiol Biomarkers Prev; 22(9); 1490-7. Ó2013 AACR.