The incidence of early-onset colorectal cancer (CRC), which occurs in individuals <50 years of age, has been increasing worldwide and particularly in high-income countries. The reasons for this ...increase remain unknown but plausible hypotheses include greater exposure to potential risk factors, such as a Western-style diet, obesity, physical inactivity and antibiotic use, especially during the early prenatal to adolescent periods of life. These exposures can not only cause genetic and epigenetic alterations in colorectal epithelial cells but also affect the gut microbiota and host immunity. Early-onset CRCs have differential clinical, pathological and molecular features compared with later-onset CRCs. Certain existing resources can be utilized to elucidate the aetiology of early-onset CRC and inform the development of effective prevention, early detection and therapeutic strategies; however, additional life-course cohort studies spanning childhood and young adulthood, integrated with prospective biospecimen collections, omics biomarker analyses and a molecular pathological epidemiology approach, are needed to better understand and manage this disease entity. In this Perspective, we summarize our current understanding of early-onset CRC and discuss how we should strategize future research to improve its prevention and clinical management.
Serrated polyps (SPs) and conventional adenomas are precursor lesions for colorectal cancer (CRC), but they are believed to arise via distinct pathways. We characterized risk factor profiles for SPs ...and conventional adenomas in a post hoc analysis of data from 3 large prospective studies.
We collected data from the Nurses’ Health Study, the Nurses’ Health Study 2, and the Health Professionals Follow-up Study on subjects who developed SPs or conventional adenomas. Our analysis comprised 141,143 participants who had undergone lower gastrointestinal endoscopy, provided updated diet and lifestyle data every 2–4 years, and were followed until diagnosis of a first polyp. We assessed 13 risk factors for CRC in patients with SPs or conventional adenomas and examined the associations according to histopathology features.
We documented 7945 SPs, 9212 conventional adenomas, and 2382 synchronous SPs and conventional adenomas during 18–20 years of follow-up. Smoking, body mass index, alcohol intake, family history of CRC, and height were associated with higher risk of SPs and conventional adenomas, whereas higher intake of vitamin D and marine omega-3 fatty acid were associated with lower risk. The associations tended to be stronger for synchronous SPs and conventional adenomas. Smoking, body mass index, and alcohol intake were more strongly associated with SPs than conventional adenomas (P for heterogeneity <.05), whereas physical activity and intake of total folate and calcium were inversely associated with conventional adenomas but not SPs. For SPs and conventional adenomas, the associations tended to be stronger for polyps in the distal colon and rectum, of 10 mm or larger or with advanced histology.
In an analysis of data from 3 large prospective studies, we found that although SPs and conventional adenomas share many risk factors, some factors are more strongly associated with one type of lesion than the other. These findings provide support for the etiologic heterogeneity of colorectal neoplasia.
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Endoscopic screening reduces incidence and mortality of colorectal cancer (CRC) because precursor lesions, such as conventional adenomas or serrated polyps, are removed. Individuals with ...polypectomies are advised to undergo colonoscopy surveillance to prevent CRC. However, guidelines for surveillance intervals after diagnosis of a precursor lesion, particularly for individuals with serrated polyps, vary widely, and lack sufficient supporting evidence. Consequently, some high-risk patients do not receive enough surveillance and lower-risk subjects receive excessive surveillance.
We examined the association between findings from first endoscopy and CRC risk among 122,899 participants who underwent flexible sigmoidoscopy or colonoscopy in the Nurses’ Health Study 1 (1990–2012), Nurses’ Health Study 2 (1989–2013), or the Health Professionals Follow-up Study (1990–2012). Endoscopic findings were categorized as no polyp, conventional adenoma, or serrated polyp (hyperplastic polyp, traditional serrated adenoma, or sessile serrated adenoma, with or without cytological dysplasia). Conventional adenomas were classified as advanced (≥10 mm, high-grade dysplasia, or tubulovillous or villous histology) or nonadvanced, and serrated polyps were assigned to categories of large (≥10 mm) or small (<10 mm). We used a Cox proportional hazards regression model to calculate the hazard ratios (HRs) of CRC incidence, after adjusting for various potential risk factors.
After a median follow-up period of 10 years, we documented 491 incident cases of CRC: 51 occurred in 6161 participants with conventional adenomas, 24 in 5918 participants with serrated polyps, and 427 in 112,107 participants with no polyp. Compared with participants with no polyp detected during initial endoscopy, the multivariable HR for incident CRC in individuals with an advanced adenoma was 4.07 (95% confidence interval CI 2.89–5.72) and the HR for CRC in individuals with a large serrated polyp was 3.35 (95% CI 1.37–8.15). In contrast, there was no significant increase in risk of CRC in patients with nonadvanced adenomas (HR 1.21; 95% CI 0.68–2.16, P = .52) or small serrated polyps (HR 1.25; 95% CI 0.76–2.08; P = .38).
These findings provide support for guidelines that recommend repeat lower endoscopy within 3 years of a diagnosis of advanced adenoma and large serrated polyps. In contrast, patients with nonadvanced adenoma or small serrated polyps may not require more intensive surveillance than patients without polyps.
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Colonoscopy and sigmoidoscopy provide protection against colorectal cancer, but the magnitude and duration of protection, particularly against cancer of the proximal colon, remain uncertain.
We ...examined the association of the use of lower endoscopy (updated biennially from 1988 through 2008) with colorectal-cancer incidence (through June 2010) and colorectal-cancer mortality (through June 2012) among participants in the Nurses' Health Study and the Health Professionals Follow-up Study.
Among 88,902 participants followed over a period of 22 years, we documented 1815 incident colorectal cancers and 474 deaths from colorectal cancer. With endoscopy as compared with no endoscopy, multivariate hazard ratios for colorectal cancer were 0.57 (95% confidence interval CI, 0.45 to 0.72) after polypectomy, 0.60 (95% CI, 0.53 to 0.68) after negative sigmoidoscopy, and 0.44 (95% CI, 0.38 to 0.52) after negative colonoscopy. Negative colonoscopy was associated with a reduced incidence of proximal colon cancer (multivariate hazard ratio, 0.73; 95% CI, 0.57 to 0.92). Multivariate hazard ratios for death from colorectal cancer were 0.59 (95% CI, 0.45 to 0.76) after screening sigmoidoscopy and 0.32 (95% CI, 0.24 to 0.45) after screening colonoscopy. Reduced mortality from proximal colon cancer was observed after screening colonoscopy (multivariate hazard ratio, 0.47; 95% CI, 0.29 to 0.76) but not after sigmoidoscopy. As compared with colorectal cancers diagnosed in patients more than 5 years after colonoscopy or without any prior endoscopy, those diagnosed in patients within 5 years after colonoscopy were more likely to be characterized by the CpG island methylator phenotype (CIMP) (multivariate odds ratio, 2.19; 95% CI, 1.14 to 4.21) and microsatellite instability (multivariate odds ratio, 2.10; 95% CI, 1.10 to 4.02).
Colonoscopy and sigmoidoscopy were associated with a reduced incidence of cancer of the distal colorectum; colonoscopy was also associated with a modest reduction in the incidence of proximal colon cancer. Screening colonoscopy and sigmoidoscopy were associated with reduced colorectal-cancer mortality; only colonoscopy was associated with reduced mortality from proximal colon cancer. Colorectal cancer diagnosed within 5 years after colonoscopy was more likely than cancer diagnosed after that period or without prior endoscopy to have CIMP and microsatellite instability. (Funded by the National Institutes of Health and others.).
The molecular features of colorectal tumors differ with their anatomic location. Colorectal tumors are usually classified as proximal or distal. We collected data from 3 cohorts to identify ...demographic, clinical, anthropometric, lifestyle, and dietary risk factors for colorectal cancer (CRC) at 7 anatomic subsites. We examined whether the associations differ among refined subsites and whether there are trends in associations from cecum to rectum.
We collected data from the Nurses’ Health Study, Nurses’ Health Study 2, and Health Professionals Follow-up Study (45,351 men and 178,016 women, followed for a median 23 years) on 24 risk factors in relation to risk of cancer in cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectosigmoid junction, and rectum. Hazard ratios were estimated using Cox proportional hazards regression. We tested for linear and nonlinear trends in associations with CRC among subsites and within proximal colon, distal colon, and rectum.
We documented 3058 cases of CRC (474 in cecum, 633 in ascending colon, 250 in transverse colon, 221 in descending colon, 750 in sigmoid colon, 202 in rectosigmoid junction, and 528 in rectum). The positive associations with cancer risk decreased, from cecum to rectum, for age and family history of CRC. In contrast, the inverse associations with cancer risk increased, from cecum to rectum, for endoscopic screening and intake of whole grains, cereal fiber, and processed red meat. There was a significant nonlinear trend in the association between CRC and female sex, with hazard ratios ranging from 1.73 for ascending colon cancer to 0.54 for sigmoid colon cancer. For proximal colon cancers, the association with alcohol consumption and smoking before age 30 years increased from the cecum to transverse colon. For distal colon cancers, the positive association with waist circumference in men was greater for descending vs sigmoid colon cancer.
In an analysis of 3058 cases of CRC, we found that risk factor profiles differed for cancers along the colorectum. Proximal vs distal classifications are not sufficient to encompass the regional variations in colorectal tumor features and risk factors.
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The influence of adiposity over life course on cancer risk remains poorly understood. We assessed trajectories of body shape from age 5 up to 60 using a group‐based modeling approach among 73,581 ...women from the Nurses' Health Study and 32,632 men from the Health Professionals Follow‐up Study. After a median of approximately 10 years of follow‐up, we compared incidence of total and obesity‐related cancers (cancers of the esophagus adenocarcinoma only, colorectum, pancreas, breast after menopause, endometrium, ovaries, prostate advanced only, kidney, liver and gallbladder) between these trajectories. We identified five distinct trajectories of body shape: lean‐stable, lean‐moderate increase, lean‐marked increase, medium‐stable, and heavy‐stable/increase. Compared with women in the lean‐stable trajectory, those in the lean‐marked increase and heavy‐stable/increase trajectories had a higher cancer risk in the colorectum, esophagus, pancreas, kidney, and endometrium (relative risk RR ranged from 1.22 to 2.56). Early life adiposity was inversely while late life adiposity was positively associated with postmenopausal breast cancer risk. In men, increased body fatness at any life period was associated with a higher risk of esophageal adenocarcinoma and colorectal cancer (RR ranged from 1.23 to 3.01), and the heavy‐stable/increase trajectory was associated with a higher risk of pancreatic cancer, but lower risk of advanced prostate cancer. The trajectory‐cancer associations were generally stronger for non‐smokers and women who did not use menopausal hormone therapy. In conclusion, trajectories of body shape throughout life were related to cancer risk with varied patterns by sex and organ, indicating a role for lifetime adiposity in carcinogenesis.
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Adult obesity raises the risk of several cancers, but the influence of body fatness across the lifespan on the likelihood of ultimately developing cancer remains poorly understood. Here, systematic assessment of the association of body shape with cancer risk reveals relationships between body‐shape trajectory throughout life and cancer risk. Individuals whose body shape increased at any life stage had an overall increased risk of developing cancer. Cancers associated with body‐shape trajectories varied by sex and organ. The findings indicate that lifetime adiposity can influence carcinogenesis, emphasizing the importance of body‐weight management throughout life for cancer prevention.
The US Preventive Services Task Force recently recommended the use of aspirin to prevent colorectal cancer and cardiovascular disease among many US adults. However, the association of aspirin use ...with the risk for other cancer types and the potential population-wide effect of aspirin use on cancer, particularly within the context of screening, remain uncertain.
To examine the potential benefits of aspirin use for overall and subtype-specific cancer prevention at a range of doses and durations of use and to estimate the absolute benefit of aspirin in the context of screening.
Two large US prospective cohort studies, the Nurses' Health Study (1980-2010) and Health Professionals Follow-up Study (1986-2012), followed up 135 965 health care professionals (88 084 women and 47 881 men, respectively) who reported on aspirin use biennially. The women were aged 30 to 55 years at enrollment in 1976; the men, aged 40 to 75 years in 1986. Final follow-up was completed on June 30, 2012, for the Nurses' Health Study cohort and January 31, 2010, for the Health Professionals Follow-up Study cohort, and data were accessed from September 15, 2014, to December 17, 2015.
Relative risks (RRs) for incident cancers and population-attributable risk (PAR).
Among the 88 084 women and 47 881 men who underwent follow-up for as long as 32 years, 20 414 cancers among women and 7571 cancers among men were documented. Compared with nonregular use, regular aspirin use was associated with a lower risk for overall cancer (RR, 0.97; 95% CI, 0.94-0.99), which was primarily owing to a lower incidence of gastrointestinal tract cancers (RR, 0.85; 95% CI, 0.80-0.91), especially colorectal cancers (RR, 0.81; 95% CI, 0.75-0.88). The benefit of aspirin on gastrointestinal tract cancers appeared evident with the use of at least 0.5 to 1.5 standard aspirin tablets per week; the minimum duration of regular use associated with a lower risk was 6 years. Among individuals older than 50 years, regular aspirin use could prevent 33 colorectal cancers per 100 000 person-years (PAR, 17.0%) among those who had not undergone a lower endoscopy and 18 colorectal cancers per 100 000 person-years (PAR, 8.5%) among those who had. Regular aspirin use was not associated with the risk for breast, advanced prostate, or lung cancer.
Long-term aspirin use was associated with a modest but significantly reduced risk for overall cancer, especially gastrointestinal tract tumors. Regular aspirin use may prevent a substantial proportion of colorectal cancers and complement the benefits of screening.
Background & Aims Western and prudent dietary patterns have been associated with higher and lower risks of colorectal cancer (CRC), respectively. However, little is known about the associations ...between dietary patterns and specific anatomic subsites or molecular subtypes of CRC. Methods We used multivariable Cox proportional hazards models to examine the associations between Western and prudent dietary patterns and CRC risk in the Health Professionals Follow-up Study and Nurses’ Health Study. Results After up to 32 years of follow-up of 137,217 men and women, we documented 3260 cases of CRC. Among individuals from whom subsite data were available, we observed 1264 proximal colon, 866 distal colon, and 670 rectal tumors. Western diet was associated with an increased incidence of CRC (Ptrend < .0001), with a relative risk (RR) of 1.31 (95% CI, 1.15–1.48, comparing the highest to lowest quartile). The association of Western diet with CRC was evident for tumors of the distal colon (RR, 1.55; 95% CI, 1.22–1.96; Ptrend = .0004) and rectum (RR, 1.35; 95% CI, 1.03–1.77; Ptrend = .01) but not proximal colon (RR, 1.11; 95% CI, 0.91–1.35; Ptrend = .51) when we comparing extreme quartiles. In contrast, for the prudent pattern, we observed a RR of 0.86 for overall CRC (95% CI, 0.77–0.95; Ptrend = .01), with similar trends at anatomic subsites. However, the trend appeared stronger among men than women. Among 1285 cases (39%) with tissue available for molecular profiling, Western diet appeared to be more strongly associated with some CRC molecular subtypes (no mutations in KRAS KRAS wildtype or BRAF BRAF wildtype, no or a low CpG island methylator phenotype, and microsatellite stability), although formal tests for heterogeneity did not produce statistically significant results. Conclusions Western dietary patterns are associated with an increased risk of CRC, particularly distal colon and rectal tumors. Western dietary patterns also appear more strongly associated with tumors that are KRAS wildtype, BRAF wildtype, have no or a low CpG island methylator phenotype, and microsatellite stability. In contrast, prudent dietary patterns are associated with a lower risk of CRC that does not vary according to anatomic subsite or molecular subtype.
Although the association between red meat consumption and colorectal cancer (CRC) is well established, the association across subsites of the colon and rectum remains uncertain, as does time of ...consumption in relation to cancer development. As these relationships are key for understanding the pathogenesis of CRC, they were examined in two large cohorts with repeated dietary measures over time, the Nurses' Health Study (n = 87,108 women, 1980-2010) and Health Professionals Follow-up Study (n = 47,389 men, 1986-2010). Cox proportional hazards regression models generated hazard ratios (HRs) and 95% confidence intervals (CIs), which were pooled by random-effects meta-analysis. In combined cohorts, there were 2,731 CRC cases (1,151 proximal colon, 816 distal colon, and 589 rectum). In pooled analyses, processed red meat was positively associated with CRC risk (per 1 serving/day increase: HR = 1.15, 95% CI: 1.01-1.32; P for trend 0.03) and particularly with distal colon cancer (per 1 serving/day increase; HR = 1.36; 95% CI: 1.09-1.69; P for trend 0.006). Recent consumption of processed meat (within the past 4 years) was not associated with distal cancer. Unprocessed red meat was inversely associated with risk of distal colon cancer and a weak non-significant positive association between unprocessed red meat and proximal cancer was observed (per 1 serving/day increase: distal HR = 0.75; 95% CI: 0.68-0.82; P for trend <0.001; proximal HR = 1.14, 95% CI: 0.92-1.40; P for trend 0.22). Thus, in these two large cohorts of US health professionals, processed meat intake was positively associated with risk of CRC, particularly distal cancer, with little evidence that higher intake of unprocessed red meat substantially increased risk of CRC. Future studies, particularly those with sufficient sample size to assess associations by subsites across the colon are needed to confirm these findings and elucidate potentially distinct mechanisms underlying the relationship between processed meat and subtypes of unprocessed red meat with CRC.
Purpose Blockade of the programmed cell death 1 (PDCD1, PD-1) immune checkpoint pathway can improve clinical outcomes in various malignancies. Evidence suggests that aspirin (a widely used ...nonsteroidal anti-inflammatory drug) not only prolongs colorectal cancer survival, but can also activate T cell-mediated antitumor immunity and synergize with immunotherapy through inhibition of prostaglandin E2 production. We hypothesized that the survival benefit associated with aspirin might be stronger in colorectal carcinoma with a lower CD274 (PDCD1 ligand 1, PD-L1) expression level that resulted in lower signaling of the immune checkpoint pathway. Patients and Methods Using data from 617 patients with rectal and colon cancer in the Nurses' Health Study and the Health Professionals Follow-Up Study, we examined the association of postdiagnosis aspirin use with patient survival in strata of tumor CD274 expression status measured by immunohistochemistry. We used multivariable Cox proportional hazards regression models to control for potential confounders, including disease stage, microsatellite instability status, CpG island methylator phenotype, long interspersed nucleotide element-1 methylation, cyclooxygenase-2 (PTGS2), and CDX2 expression, and KRAS, BRAF, and PIK3CA mutations. Results The association of postdiagnosis aspirin use with colorectal cancer-specific survival differed by CD274 expression status ( P
< .001); compared with aspirin nonusers; multivariable-adjusted hazard ratios for regular aspirin users were 0.16 (95% CI, 0.06 to 0.41) in patients with low CD274 and 1.01 (95% CI, 0.61 to 1.67) in patients with high CD274. This differential association seemed consistent in patients with microsatellite-stable or PIK3CA wild-type disease and in strata of PTGS2 expression, CDX2 expression, tumor-infiltrating lymphocytes, or prediagnosis aspirin use status. Conclusion The association of aspirin use with colorectal cancer survival is stronger in patients with CD274-low tumors than CD274-high tumors. Our findings suggest a differential antitumor effect of aspirin according to immune checkpoint status.
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