Clinical and Genetic Factors to Inform Reducing Colorectal Cancer Disparitites in African Americans

Potential role of the Eph/ephrin system in colorectal cancer: emerging druggable molecular targets

The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. In colorectal cancer (CRC), it is involved in different processes including tumorigenesis, tumor angiogenesis, metastasis development, and cancer stem cell regeneration. However, conflicting data regarding Eph receptors in CRC, especially in its putative role as an oncogene or a suppressor gene, make the precise role of Eph-ephrin interaction confusing in CRC development. In this review, we provide an overview of the literature and highlight evidence that collaborates with these ambiguous roles of the Eph/ephrin system in CRC, as well as the molecular findings that represent promising therapeutic targets.

Initial Stage of Disease Similar for White and Black Patients With Early-Onset Colorectal Cancer at a Safety-Net Hospital

BACKGROUND

Non-Hispanic Black (NHB) patients with early-onset colorectal cancer (EOCRC) are more likely to present with advanced-stage disease than their Non-Hispanic White (NHW) counterparts. To further elucidate whether differences in tumor biology or disparities in access to care may be responsible, we examined the association between race/ethnicity and initial stage of disease, time to diagnosis, and tumor characteristics among NHW and NHB patients with EOCRC cared for in a safety-net health care setting.

METHODS

We performed a retrospective cohort study of NHW and NHB patients diagnosed with primary EOCRC who received care at Boston Medical Center between January 2000 and May 2020. We compared demographics, risk factors, presenting signs/symptoms, time to diagnosis, health care utilization, and tumor characteristics (stage, grade, location, and mutational status).

RESULTS

We identified 103 patients (mean age 41.5±7.2 y, 53.4% men), including 40 NHWs and 63 NHBs, with EOCRC. NHB and NHW patients were similar with respect to demographics, presenting signs/symptoms, and risk factor distribution. There were also no significant differences between NHWs and NHBs with respect to the advanced stage of disease at presentation (45.0% vs. 42.9%, P =0.83), the median time to diagnosis [152 d (IQR, 40 to 341) vs. 160 d (IQR, 61 to 312), P =0.79] or tumor characteristics, except for a predilection for proximal disease among NHBs (30.2% vs. 15.0%).

CONCLUSIONS

NHB patients were no more likely than NHW patients to present with advanced-stage disease, aggressive tumor histology, or experience delays in diagnosis within a safety-net health care system.

Socioeconomic status on survival outcomes in patients with colorectal cancer: a cross-sectional study

BACKGROUND

Colorectal cancer (CRC) is widely acknowledged as a prevalent malignancy and the second most common cause of cancer-related mortality worldwide. The aim of this study was to examine the independent impact of Median Household Income (MHI) on prognosis and survival outcomes in patients with CRC.

METHODS

Data from 17 cancer registries of the United States Surveillance, Epidemiology, and End Results program, with follow-up extended until November 2022 was analyzed. A Cox proportional hazards regression analysis was conducted to evaluate the influence of different levels of MHI on survival outcomes among patients with CRC. A total of 761,697 CRC patient records were retrieved from the SEER database.

RESULTS

The Cox regression analysis results indicated that patients with higher MHI exhibited improved overall survival outcomes when compared to those with lower MHI (MMHI: P < 0.001; HMHI: P < 0.001). Regardless of the specific tumor location, gender, stage of CRC, or treatment method, higher MHI is consistently linked to improved survival outcomes. However, this association was not found to be statistically significant among American Indian/Alaska Native (MMHI: P = 0.017; HMHI: P = 0.081), Asian or Pacific Islander (MMHI: P = 0.223; HMHI: P = 0.002) and unmarried or domestic partner patients (MMHI: P = 0.311; HMHI: P = 0.011).

CONCLUSION

These results emphasize the importance of considering socioeconomic factors, such as income level, in understanding and addressing disparities in survival outcomes of CRC patients.

Racial disparities in cancer care, an eyeopener for developing better global cancer management strategies

BACKGROUND

In the last few decades, advancements in cancer research, both in the field of cancer diagnostics as well as treatment of the disease have been extensive and multidimensional. Increased availability of health care resources and growing awareness has resulted in the reduction of consumption of carcinogens such as tobacco; adopting various prophylactic measures; cancer testing on regular basis and improved targeted therapies have greatly reduced cancer mortality among populations, globally. However, this notable reduction in cancer mortality is discriminate and reflective of disparities between various ethnic populations and economic classes. Several factors contribute to this systemic inequity, at the level of diagnosis, cancer prognosis, therapeutics, and even point-of-care facilities.

RECENT FINDINGS

In this review, we have highlighted cancer health disparities among different populations around the globe. It encompasses social determinants such as status in society, poverty, education, diagnostic approaches including biomarkers and molecular testing, treatment as well as palliative care. Cancer treatment is an active area of constant progress and newer targeted treatments like immunotherapy, personalized treatment, and combinatorial therapies are emerging but these also show biases in their implementation in various sections of society. The involvement of populations in clinical trials and trial management is also a hotbed for racial discrimination. The immense progress in cancer management and its worldwide application needs a careful evaluation by identifying the biases in racial discrimination in healthcare facilities.

CONCLUSION

Our review gives a comprehensive evaluation of this global racial discrimination in cancer care and would be helpful in designing better strategies for cancer management and decreasing mortality.

Trends in Colorectal Cancer Mortality in the United States, 1999 - 2020

Background

The United States faces a significant public health issue with colorectal cancer (CRC), which remains the third leading cause of cancer-related fatalities despite early diagnosis and treatment progress.

Methods

This investigation utilized death certificate data from the Centers for Disease Control and Prevention Wide-Ranging OnLine Data for Epidemiologic Research (CDC WONDER) database to investigate trends in CRC mortality and location of death from 1999 to 2020. Additionally, the study utilized the annual percent change (APC) to estimate the average annual rate of change over the specific time period for the given health outcome. Incorporating the location of death in this study served the purpose of identifying patterns related to CRC and offering valuable insights into the specific locations where deaths occurred.

Results

Between 1999 and 2020, there were 1,166,158 CRC-related deaths. The age-adjusted mortality rates (AAMRs) for CRC consistently declined from 20.7 in 1999 to 12.5 in 2020. Men had higher AAMR (18.8) than women (13.4) throughout the study. Black or African American patients had the highest AAMR (21.1), followed by White (15.4), Hispanic/Latino (11.8), American Indian or Alaska native (11.4), and Asian or Pacific Islanders (10.2). The location of death varied, with 41.99% at home, 28.16% in medical facilities, 16.6% in nursing homes/long-term care facilities, 7.43% in hospices, and 5.80% at other/unknown places.

Conclusion

There has been an overall improvement in AAMR among most ethnic groups, but an increase in AAMR has been observed among white individuals below the age of 55. Notably, over one-quarter of CRC-related deaths occur in medical facilities.

Prediagnostic 25-Hydroxyvitamin D in Association with Cancer-specific and All-cause Mortality among Low-income, Non-Hispanic Black Americans with Colorectal Cancer

BACKGROUND

Observational studies show high prediagnosis 25-hydroxyvitamin D is associated with lower mortality after colorectal cancer diagnosis. Results from clinical trials suggest vitamin D supplementation may improve outcomes among patients with colorectal cancer. Most studies included few Black Americans, who typically have lower 25-hydroxyvitamin D. We evaluated associations between serum 25-hydroxyvitamin D and mortality after colorectal cancer diagnosis among Black American cases.

METHODS

Data arose from 218 Black Americans from the Southern Community Cohort Study diagnosed with colorectal cancer during follow-up (age 40-79 at enrollment). Prediagnostic 25-hydroxyvitamin D was measured at enrollment and categorized as deficient (<12 ng/mL), insufficient (12-19.9 ng/mL), or sufficient (≥20 ng/mL). Mortality was determined from the National Death Index. Cox proportional hazards were used to estimate HRs and 95% confidence intervals (CI) for associations between 25-hydroxyvitamin D and mortality.

RESULTS

As a continuous exposure, higher 25-hydroxyvitamin D was associated with overall mortality [HR = 0.79 (0.65-0.96) per-SD increase, Ptrend = 0.02] and colorectal cancer-specific mortality [HR = 0.83 (0.64-1.08), Ptrend = 0.16]. For overall mortality, associations were strongest among females [HR = 0.65 (0.42-0.92)], current smokers [HR = 0.61 (0.38-0.98)], and obese participants [HR = 0.47 (0.29-0.77)]. Compared with those with deficiency, participants with sufficient 25-hydroxyvitamin D had lower overall mortality after multivariable adjustment [HR: 0.61 (0.37-1.01)].

CONCLUSIONS

Prediagnosis 25-hydroxyvitamin D is inversely associated with overall and colorectal cancer-specific mortality among Black Americans with colorectal cancer. Correcting vitamin D deficiency may improve survival of these patients, particularly for obese individuals and smokers.

IMPACT

Our results support including more Black Americans in trials of vitamin D supplementations to improve colorectal cancer outcomes.

A correlation study affecting survival in patients after radical colon cancer surgery: A retrospective study

The objective of this study was to explore the relevant factors affecting the 5-year survival rate of patients after radical colon cancer surgery, and to provide some basis for improving the quality of life and prognosis of colon cancer patients. The clinical data of 116 colon cancer patients who underwent treatment in our hospital from January 2017 to December 2017 were retrospectively selected. Using the date of performing surgical treatment as the starting point and the completion of 5 years after surgery or patient death as the end point, all patients were followed up by telephone to count the 5-year survival rate and analyze the influence of each factor with the prognosis of colon cancer patients. Of the 116 patients, 14 patients were lost to follow-up. Of the 102 patients with complete follow-up, 33 patients were died, with an overall 5-year survival rate of 67.6%. After univariate analysis, it was found that distant metastasis (χ2 = 10.493, P = .001), lymph node metastasis (χ2 = 25.145, P < .001), depth of muscle infiltration (χ2 = 14.929, P < .001), alcohol consumption (χ2 = 15.263, P < .001), and preoperative obstruction (χ2 = 9.555, P = .002) were significantly associated with the prognosis of colon cancer patients. Multivariate logistic analysis showed that distant metastasis (odds ratio [OR]: 1.932, 95% confidence intervals [CI]: 1.272-2.934, P = .002), lymph node metastasis (OR: 1.219, 95% CI: 1.091-1.362, P < .001), and obstruction (OR: 1.970, 95% CI: 1.300-2.990, P < .001) were significant independent risk factors affecting the prognosis in patients after radical colon cancer surgery. In summary, preoperative obstruction, lymph node metastasis, and distant metastasis are independent factors influencing 5-year survival rate after radical colon cancer surgery. Patients with risk factors should be followed up more closely and reasonable postoperative adjuvant chemotherapy regimens should be used to improve long-term survival.

Examining colorectal cancer screening uptake and health provider recommendations among underserved middle aged and older African Americans

Background: The purpose of this study is to determine whether underserved middle-aged and older African Americans are receiving a colorectal cancer (CRC) screening test (sigmoidoscopy or colonoscopy) and if recommended by their provider. Additionally, we examined correlates of both provider recommendation and uptake of CRC screening. Methods: Seven hundred forty African American individuals, aged 55 and older, participated in this local community cross-sectional survey. We used a multivariate technique of logistic regression. Results: One out of three participants reported that they never received a sigmoidoscopy or colonoscopy for CRC screening. More than 31% indicted that their providers never suggested CRC testing. However, participants who indicated that their providers recommended sigmoidoscopy/colonoscopy were almost 49 times (odds ratio [OR]: 48.9, 95% confidence interval [CI]: 29.5-81.2) more likely to obtain it compared to their counterparts who were not advised to have these procedures. Our data suggest that African American men were significantly less likely than women to receive recommendations from their providers (OR: 0.70, 95% CI: 0.50-0.91). Furthermore, controlling for other variables, the following factors: 1) living arrangement (OR: 1.44, 95% CI: 1.02-2.04), 2) health maintenance organization (HMO) membership (OR: 1.84, 95% CI: 1.28-2.67), 3) number of providers (OR: 1.15, 95% CI: 1.01-1.32), 4) satisfaction with access to and quality of care (OR: 1.24, 95% CI: 1.03-1.51), 5) depressive symptoms (OR: 0.92, 95% CI: 0.86-0.98), and 6) gastrointestinal conditions (OR: 1.73, 95% CI: 1.16-2.58) were associated with obtaining a sigmoidoscopy or colonoscopy test. Conclusion: Our findings suggest that the absence of a provider recommendation is the primary barrier preventing underserved older African Americans from obtaining CRC screening. In addition, our data revealed significant association between obtaining CRC screening and some of the predisposing characteristics of participants, satisfaction with access to and quality of care, and physical and mental health. These findings are consistent with this notion that disparities in health care for African Americans can be traced back to four primary factors: patients, healthcare providers, the healthcare system, and society as a whole, and emphasize the need for establishing theory-driven, culturally-sensitive, and cost-effective CRC screening interventions that recognize and address the constraints to cancer screening experienced by this segment of population.

Epigenome-Wide Study Identifies Epigenetic Outliers in Normal Mucosa of Patients with Colorectal Cancer

Nongenetic predisposition to colorectal cancer continues to be difficult to measure precisely, hampering efforts in targeted prevention and screening. Epigenetic changes in the normal mucosa of patients with colorectal cancer can serve as a tool in predicting colorectal cancer outcomes. We identified epigenetic changes affecting the normal mucosa of patients with colorectal cancer. DNA methylation profiling on normal colon mucosa from 77 patients with colorectal cancer and 68 controls identified a distinct subgroup of normally-appearing mucosa with markedly disrupted DNA methylation at a large number of CpGs, termed as "Outlier Methylation Phenotype" (OMP) and are present in 15 of 77 patients with cancer versus 0 of 68 controls (P < 0.001). Similar findings were also seen in publicly available datasets. Comparison of normal colon mucosa transcription profiles of patients with OMP cancer with those of patients with non-OMP cancer indicates genes whose promoters are hypermethylated in the OMP patients are also transcriptionally downregulated, and that many of the genes most affected are involved in interactions between epithelial cells, the mucus layer, and the microbiome. Analysis of 16S rRNA profiles suggests that normal colon mucosa of OMPs are enriched in bacterial genera associated with colorectal cancer risk, advanced tumor stage, chronic intestinal inflammation, malignant transformation, nosocomial infections, and KRAS mutations. In conclusion, our study identifies an epigenetically distinct OMP group in the normal mucosa of patients with colorectal cancer that is characterized by a disrupted methylome, altered gene expression, and microbial dysbiosis. Prospective studies are needed to determine whether OMP could serve as a biomarker for an elevated epigenetic risk for colorectal cancer development.

PREVENTION RELEVANCE

Our study identifies an epigenetically distinct OMP group in the normal mucosa of patients with colorectal cancer that is characterized by a disrupted methylome, altered gene expression, and microbial dysbiosis. Identification of OMPs in healthy controls and patients with colorectal cancer will lead to prevention and better prognosis, respectively.

Commencing colorectal cancer screening at age 45 years in U.S. racial groups

Screening for colorectal cancer (CRC) is cost-effective for reducing its mortality among the average-risk population. In the US, CRC incidence and mortality differ among racial/ethnic groups, with non-Hispanic Blacks (NHB) and American Indian/Alaska Natives showing highest incidence and mortality and earlier presentation. Since 2005, some professional societies have recommended CRC screening for NHB to commence at 45 years or earlier; this was not implemented due to lack of recommendation from key groups that influence insurance payment coverage. In 2017 the highly influential U.S. Multi-Society Task Force for Colorectal Cancer recommended screening to commence at 45 years for NHB; this recommendation was supplanted by data showing an increase in early-onset CRCs in non-Hispanic Whites approaching the under-50-year rates observed for NHB. Subsequently the American Cancer Society and the USPSTF recommended that the entire average-risk population move to commence CRC screening at 45 years. Implementing screening in 45–49-year-olds has its challenges as younger groups compared with older groups participate less in preventive care. The US had made extensive progress pre-COVID-19 in closing the disparity gap for CRC screening in NHB above age 50 years; implementing screening at younger ages will take ingenuity, foresight, and creative strategy to reach a broader-aged population while preventing widening the screening disparity gap. Approaches such as navigation for non-invasive and minimally invasive CRC screening tests, removal of financial barriers such as co-pays, and complete follow up to abnormal non-invasive screening tests will need to become the norm for broad implementation and success across all racial/ethnic groups.

Inflammation, microbiome and colorectal cancer disparity in African-Americans: Are there bugs in the genetics?

Dysregulated interactions between host inflammation and gut microbiota over the course of life increase the risk of colorectal cancer (CRC). While environmental factors and socio-economic realities of race remain predominant contributors to CRC disparities in African-Americans (AAs), this review focuses on the biological mediators of CRC disparity, namely the under-appreciated influence of inherited ancestral genetic regulation on mucosal innate immunity and its interaction with the microbiome. There remains a poor understanding of mechanisms linking immune-related genetic polymorphisms and microbiome diversity that could influence chronic inflammation and exacerbate CRC disparities in AAs. A better understanding of the relationship between host genetics, bacteria, and CRC pathogenesis will improve the prediction of cancer risk across race/ethnicity groups overall.

Opportunities for personalizing colorectal cancer care: an analysis of SEER-medicare data

United States clinical practice guidelines for metastatic colorectal cancer recommend use of medications impacted by genetic variants but do not recommend testing. We analyzed real-world treatment using a cancer registry and claims dataset to explore pharmacogenomic (PGx) medication treatment patterns and characterize exposure. In a cohort of 6957 patients, most (86.9%) were exposed to at least one chemotherapy medication with PGx guidelines. In a cohort of 2223 patients with retail pharmacy claims available, most (79.2%) were treated with at least one non-chemotherapy (79.2%) medication with PGx guidelines. PGx-associated chemotherapy exposure was associated with age, race/ethnicity, educational attainment, and rurality. PGx-associated non-chemotherapy exposure was associated with medication use and comorbidities. The potential impact of PGx testing is large and policies aimed at increasing PGx testing at diagnosis may impact treatment decisions for patients with metastatic colorectal cancer as most patients are exposed to medications with pharmacogenomics implications during treatment.

Engaging the Community on Colorectal Cancer Screening Education: Focus Group Discussions Among African Americans

Colorectal cancer (CRC) is the third most diagnosed cancer in the USA, and African Americans experience disproportionate CRC diagnosis and mortality. Early detection could reduce CRC incidence and mortality, and reduce CRC health disparities, which may be due in part to lower screening adherence and later stage diagnosis among African Americans compared to whites. Culturally tailored interventions to increase access to and uptake of CRC stool-based tests are one effective strategy to increase benefits of screening among African Americans. The objectives of this study were to obtain feedback from African Americans on CRC educational materials being developed for a subsequent behavioral clinical trial and explore participants' knowledge, attitudes, and beliefs about CRC and CRC screening. Seven focus groups were conducted between February and November 2020. Participants were African Americans recruited through community contacts. Four focus groups were held in-person and three were conducted virtually due to Covid-19 restrictions. Participants ranked CRC educational text messages and provided feedback on a culturally tailored educational brochure. A focus group guide with scripted probes was used to elicit discussion and transcripts were analyzed using traditional content analysis. Forty-two African Americans participated. Four themes were identified from focus group discussions: (1) knowledge, attitudes, and beliefs on CRC and CRC screening; (2) reliable sources of cancer education information; (3) cultural factors affecting perspectives on health; and (4) community insights into cancer education. Participant input on the brochure was incorporated in content creation. Engaging African American community members to qualitatively examine cancer prevention has value in improving implementation strategy and planning for behavioral clinical trials.

Epidemiology and biology of early onset colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related mortality in men or women in the United States. Average-risk screening that begins at age 50 years has reduced incidence and mortality of CRC in those over 50 years of age, whereas CRC incidence in those under age 50 years (early onset colorectal cancer (eoCRC)) has recently and dramatically increased. In this review, we summarize the recent literature including risk factors for eoCRC, differences in clinicopathologic presentation and outcomes in eoCRC, and emerging evidence regarding the molecular pathways that are altered in eoCRC compared to later onset CRC (loCRC). Epidemiologic studies of eoCRC show predominance in distal colon and rectum, and association with several modifiable risk factors, including diabetes, obesity, diet, sedentary time, alcohol consumption and smoking. Data regarding potential risk factors of prior antibiotic exposure and microbiome alterations or direct carcinogen exposure are still emerging. Aggressive clinicopathologic features of eoCRC at presentation may be due to delay in diagnosis or more aggressive tumor biology. EoCRC outcomes are similar to loCRC when matched for stage, but overall mortality is greater due to higher frequency of advanced disease at a younger presentation, with more life-years lost. There are only few molecular evaluations of eoCRC to date, with findings of potential increase in TP53 and CTNNB1 somatic mutation and decrease in APC, KRAS and BRAF somatic mutation, compared to loCRC. Other findings include LINE-1 hypomethylation, absence of microsatellite instability (MSI-H), presence of chromosomal instability (CIN) or microsatellite and chromosomal stability (MACS). These studies are only now emerging and have not yet identified a specific molecular signature defining eoCRC. Further research evaluating genetic and molecular differences as well as environmental triggers for eoCRCs should provide a clearer understanding to inform targeted screening for pre-symptomatic at-risk younger individuals.

Assessing the effectiveness of a community health advisor plus screen to save educational intervention on stool-based testing adherence in an African American safety net clinic population: study protocol for a randomized pragmatic trial

Background

Colorectal cancer (CRC) is the second most deadly cancer affecting US adults and is also one of the most treatable cancers when detected at an earlier clinical stage of disease through screening. CRC health disparities experienced by African Americans are due in part to the later stage of diagnosis, suggesting the importance of improving African Americans’ CRC screening participation. The national Screen to Save (S2S) initiative employs a community health educator to deliver CRC screening education which can be tailored for specific populations, and such approaches have increased CRC screening rates in disadvantaged and racial/ethnic minority populations.

Methods/design

In this trial emphasizing stool-based CRC screening, focus groups informed the development of an adapted S2S video and brochure tailored for African Americans and identified preferred motivational text messages for a multicomponent community health advisor (CHA) intervention. A CHA hired from the community was trained to deliver a 6-week CRC educational intervention consisting of an initial face-to-face meeting followed by 5 weeks of calls and texts. Interested eligible persons are enrolled primarily through recruitment by two partnering community health centers (CHCs) and secondarily through various outreach channels and, after consenting and completing a baseline survey, are randomly assigned to one of two study arms. The CHCs are blinded to study arm assignment. Intervention arm participants receive the brochure and CHA intervention while participants assigned to the control group receive only the brochure. All participants receive a stool-based CRC screening test from their health center, and the primary outcome is the completion of the screening test at 12 months. Secondary objectives are to estimate the effect of the intervention on mediating factors, explore the effect of moderating factors, and perform a cost-effectiveness analysis of the CHA intervention.

Discussion

The TUNE-UP study will enhance understanding about CRC screening in African Americans obtaining primary health care through CHCs and is one of the very few studies to examine a CHA intervention in this context. A better understanding of the mechanisms by which the intervention affects patient beliefs and behaviors will help focus future research while the exploratory cost-effectiveness analysis will inform CHCs’ decision-making about implementing a CHA program to increase screening and reduce cancer health disparities.

Trial registration

ClinicalTrials.govNCT04304001. Registered on March 11, 2020.

The interplay of pineal hormones and socioeconomic status leading to colorectal cancer disparity

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Despite increased screening options and state-of-art treatments offered in clinics, racial differences remain in CRC. African Americans (AAs) are disproportionately affected by the disease; the incidence and mortality are higher in AAs than Caucasian Americans (CAs). At the time of diagnosis, AAs more often present with advanced stages and aggressive CRCs, primarily accounting for the racial differences in therapeutic outcomes and mortality. The early incidence of CRC in AAs could be attributed to race-specific gene polymorphisms and lifestyle choices associated with socioeconomic status (SES). Altered melatonin-serotonin signaling, besides the established CRC risk factors (age, diet, obesity, alcoholism, and tobacco use), steered by SES, glucocorticoid, and Vitamin D status in AAs could also account for the early incidence in this racial group. This review focuses on how the lifestyle factors, diet, allelic variants, and altered expression of specific genes could lead to atypical serotonin and melatonin signaling by modulating the synthesis, secretion, and signaling of these pineal hormones in AAs and predisposing them to develop more aggressive CRC earlier than CAs. Crosstalk between gut microbiota and pineal hormones and its impact on CRC pathobiology is addressed from a race-specific perspective. Lastly, the status of melatonin-focused CRC treatments, the need to better understand the perturbed melatonin signaling, and the potential of pineal hormone-directed therapeutic interventions to reduce CRC-associated disparity are discussed.

Racial disparities negatively impact outcomes in early-onset colorectal cancer independent of socioeconomic status

BACKGROUND

The incidence of colorectal cancer (CRC) in patients under age 50 is rising for unclear reasons. We examined the effects of socioeconomic factors on outcomes for patients with early-onset CRC compared to late-onset CRC.

METHODS

Patients with CRC from 2004 to 2015 in the National Cancer Database were included and categorized by age (under or over 50 years). Differences in demographic and socioeconomic factors, disease characteristics, and survival outcomes between early-onset versus late-onset CRC patients were assessed by Chi-squared test and Cox models.

RESULTS

The study population included 1,061,204 patients, 108,058 (10.2%) of whom were under age 50. The proportion of patients diagnosed under age 50 increased over time: 9.4% in 2004-2006, 10.1% in 2007-2009, 10.5% in 2010-2012, and 10.7% in 2013-2015 (p < 0.0001). Early-onset CRC patients were more likely to be Black (15.1% vs. 11.3%) or Hispanic (8.6% vs. 4.6%) and to present with stage 4 disease (24.9% vs. 17.0%), p < 0.0001 for all. Black patients had the worst median OS (58.3 months) compared to White (67.0 months), Hispanic (91.6 months), or Asian (104.9 months) patients, p < 0.0001. Within the subgroup of early-onset CRC patients with private insurance, Black patients had worse OS compared to White patients, even in communities with higher income and education status.

CONCLUSIONS

Early-onset CRC continues to increase. Patients with early-onset CRC are more likely to be Black or Hispanic and to present with stage 4 cancer. Early-onset Black patients showed worse OS compared to White patients in all income subgroups, even with private insurance.

Systematic Review of Interventions to Increase Stool Blood Colorectal Cancer Screening in African Americans

African Americans experience colorectal cancer (CRC) related disparities compared to other racial groups in the United States. African Americans are frequently diagnosed with CRC at a later stage, screening is underutilized, and mortality rates are highest in this group. This systematic review focused on intervention studies using stool blood CRC screening among African Americans in primary care and community settings. Given wide accessibility, low cost, and ease of dissemination of stool-based CRC screening tests, this review aims to determine effective interventions to improve participation rates. This systematic review included intervention studies published between January 1, 2000 and March 16, 2019. After reviewing an initial search of 650 studies, 11 studies were eventually included in this review. The included studies were studies conducted in community and clinical settings, using both inreach and outreach strategies to increase CRC screening. For each study, an unadjusted odds ratio (OR) for the CRC screening intervention compared to the control arm was calculated based on the data in each study to report effectiveness. The eleven studies together recruited a total of 3334 participants. The five studies using two-arm experimental designs ranged in effectiveness with ORs ranging from 1.1 to 13.0 using interventions such as mailed reminders, patient navigation, and tailored educational materials. Effective strategies to increase stool blood testing included mailed stool blood tests augmented by patient navigation, tailored educational materials, and follow-up calls or mailings to increase trust in the patient-provider relationship. More studies are needed on stool blood testing interventions to determine effectiveness in this population.

Racial and ethnic disparities in colorectal cancer incidence and mortality

The occurrence of colorectal cancer (CRC) shows a large disparity among recognized races and ethnicities in the U.S., with Black Americans demonstrating the highest incidence and mortality from this disease. Contributors for the observed CRC disparity appear to be multifactorial and consequential that may be initiated by structured societal issues (e.g., low socioeconomic status and lack of adequate health insurance) that facilitate abnormal environmental factors (through use of tobacco and alcohol, and poor diet composition that modifies one's metabolism, microbiome and local immune microenvironment) and trigger cancer-specific immune and genetic changes (e.g., localized inflammation and somatic driver gene mutations). Mitigating the disparity by prevention through CRC screening has been demonstrated; this has not been adequately shown once CRC has developed. Acquiring additional knowledge into the science behind the observed disparity will inform approaches towards abating both the incidence and mortality of CRC between U.S. racial and ethnic groups.

Disparities in Early-Onset Colorectal Cancer

The incidence and mortality of early-onset colorectal cancer (CRC) are increasing in the United States (US) and worldwide. In the US, there are notable disparities in early-onset CRC burden by race/ethnicity and geography. African Americans, Hispanic/Latinos, and populations residing in specific regions of the Southern U.S. are disproportionately affected with CRC diagnosed at younger ages, while less is known about disparities in other countries. Reasons for these disparities are likely multi-factorial and potentially implicate differences in health determinants including biology/genetics, diet/environment, individual health behaviors, and access to high-quality health services, as well as social and policy factors. This review summarizes current understanding of early-onset CRC disparities and identifies specific research areas that will inform evidence-based interventions at individual, practice, and policy levels to reduce the global burden of this disease.

Impact of type 2 diabetes on adenoma detection in screening colonoscopies performed in disparate populations

BACKGROUND

The Black/African Ancestry (AA) population has a higher prevalence of type 2 diabetes mellitus (T2DM) and a higher incidence and mortality rate for colorectal cancer (CRC) than all other races in the United States. T2DM has been shown to increase adenoma risk in predominantly white/European ancestry (EA) populations, but the effect of T2DM on adenoma risk in Black/AA individuals is less clear. We hypothesize that T2DM has a significant effect on adenoma risk in a predominantly Black/AA population.

AIM

To investigate the effect of T2DM and race on the adenoma detection rate (ADR) in screening colonoscopies in two disparate populations.

METHODS

A retrospective cohort study was conducted on ADR during index screening colonoscopies (age 45-75) performed at an urban public hospital serving a predominantly Black/AA population (92%) (2017-2018, n = 1606). Clinical metadata collected included basic demographics, insurance, body mass index (BMI), family history of CRC, smoking, diabetes diagnosis, and aspirin use. This dataset was combined with a recently reported parallel retrospective cohort data set collected at a suburban university hospital serving a predominantly White/EA population (87%) (2012-2015, n = 2882).

RESULTS

The ADR was higher in T2DM patients than in patients without T2DM or prediabetes (35.2% vs 27.9%, P = 0.0166, n = 981) at the urban public hospital. Multivariable analysis of the combined datasets showed that T2DM [odds ratio (OR) = 1.29, 95% confidence interval (CI): 1.08-1.55, P = 0.0049], smoking (current vs never OR = 1.47, 95%CI: 1.18-1.82, current vs past OR = 1.32, 95%CI: 1.02-1.70, P = 0.0026), older age (OR = 1.05 per year, 95%CI: 1.04-1.06, P < 0.0001), higher BMI (OR = 1.02 per unit, 95%CI: 1.01-1.03, P = 0.0003), and male sex (OR = 1.87, 95%CI: 1.62-2.15, P < 0.0001) were associated with increased ADR in the combined datasets, but race, aspirin use and insurance were not.

CONCLUSION

T2DM, but not race, is significantly associated with increased ADR on index screening colonoscopy while controlling for other factors.

Impact of preoperative antibiotics and other variables on integrated microbiome-host transcriptomic data generated from colorectal cancer resections

BACKGROUND

Integrative multi-omic approaches have been increasingly applied to discovery and functional studies of complex human diseases. Short-term preoperative antibiotics have been adopted to reduce site infections in colorectal cancer (CRC) resections. We hypothesize that the antibiotics will impact analysis of multi-omic datasets generated from resection samples to investigate biological CRC risk factors.

AIM

To assess the impact of preoperative antibiotics and other variables on integrated microbiome and human transcriptomic data generated from archived CRC resection samples.

METHODS

Genomic DNA (gDNA) and RNA were extracted from prospectively collected 51 pairs of frozen sporadic CRC tumor and adjacent non-tumor mucosal samples from 50 CRC patients archived at a single medical center from 2010-2020. The 16S rRNA gene sequencing (V3V4 region, paired end, 300 bp) and confirmatory quantitative polymerase chain reaction (qPCR) assays were conducted on gDNA. RNA sequencing (IPE, 125 bp) was performed on parallel tumor and non-tumor RNA samples with RNA Integrity Numbers scores ≥ 6.

RESULTS

PERMANOVA detected significant effects of tumor vs nontumor histology (P = 0.002) and antibiotics (P = 0.001) on microbial β-diversity, but CRC tumor location (left vs right), diabetes mellitus vs not diabetic and Black/African Ancestry (AA) vs not Black/AA, did not reach significance. Linear mixed models detected significant tumor vs nontumor histology*antibiotics interaction terms for 14 genus level taxa. QPCR confirmed increased Fusobacterium abundance in tumor vs nontumor groups, and detected significantly reduced bacterial load in the (+)antibiotics group. Principal coordinate analysis of the transcriptomic data showed a clear separation between tumor and nontumor samples. Differentially expressed genes obtained from separate analyses of tumor and nontumor samples, are presented for the antibiotics, CRC location, diabetes and Black/AA race groups.

CONCLUSION

Recent adoption of additional preoperative antibiotics as standard of care, has a measurable impact on -omics analysis of resected specimens. This study still confirmed increased Fusobacterium nucleatum in tumor.

Insights into disparities observed with COVID-19

The onset of human disease by infection with SARS-CoV-2 causing COVID-19 has revealed risk factors for disease severity. There are four identified factors that put one at high risk for infection and/or mortality creating a disparity: age, co-morbidities, race/ethnicity and gender. Data indicate that the older a person is, and/or the presence of obesity and diabetes, cardiovascular disease and chronic kidney disease place one at higher risk for COVID-19. In the United States, specific race/ethnicities, particularly African Americans and Native Americans, are strong COVID-19 risk components. Male gender has also emerged as a severity risk factor. For age and racial/ethnicities, the accumulation of health co-morbidities is common precipitating mechanisms. In particular, underlying socio-economic structures in the United States likely drive development of co-morbidities, putting affected populations at higher risk for severe COVID-19. Sudden cardiac death triggered by a common sodium channel variant in African Americans with COVID-19 has not been evaluated as a cause for racial disparity. There is no evidence that racial/ethnic differences for COVID-19 are caused by ABO blood groups, use of angiotensin-converting enzyme (ACE) inhibitors or from amino acid substitutions in the SARS-CoV-2 spike protein. There is growing evidence that androgen-enabled expression of ACE2 receptors and the serine protease TMPRSS2, two permissive elements engaging the SARS-CoV-2 spike protein for infection, may contribute to severe COVID-19 in men. Overall, COVID-19 has generated disparities for who is infected and the severity of that infection. Understanding the mechanisms for the disparity will help nullify the differences in risk for COVID-19.

Colorectal cancer incidence and mortality trends by sex and population group in South Africa: 2002-2014

BACKGROUND

South Africa (SA) has experienced a rapid transition in the Human Development Index (HDI) over the past decade, which had an effect on the incidence and mortality rates of colorectal cancer (CRC). This study aims to provide CRC incidence and mortality trends by population group and sex in SA from 2002 to 2014.

METHODS

Incidence data were extracted from the South African National Cancer Registry and mortality data obtained from Statistics South Africa (STATS SA), for the period 2002 to 2014. Age-standardised incidence rates (ASIR) and age-standardised mortality rates (ASMR) were calculated using the STATS SA mid-year population as the denominator and the Segi world standard population data for standardisation. A Joinpoint regression analysis was computed for the CRC ASIR and ASMR by population group and sex.

RESULTS

A total of 33,232 incident CRC cases and 26,836 CRC deaths were reported during the study period. Of the CRC cases reported, 54% were males and 46% were females, and among deaths reported, 47% were males and 53% were females. Overall, there was a 2.5% annual average percentage change (AAPC) increase in ASIR from 2002 to 2014 (95% CI: 0.6-4.5, p-value < 0.001). For ASMR overall, there was 1.3% increase from 2002 to 2014 (95% CI: 0.1-2.6, p-value < 0.001). The ASIR and ASMR among population groups were stable, with the exception of the Black population group. The ASIR increased consistently at 4.3% for black males (95% CI: 1.9-6.7, p-value < 0.001) and 3.4% for black females (95% CI: 1.5-5.3, p-value < 0.001) from 2002 to 2014, respectively. Similarly, ASMR for black males and females increased by 4.2% (95% CI: 2.0-6.5, p-value < 0.001) and 3.4% (, 95%CI: 2.0-4.8, p-value < 0.01) from 2002 to 2014, respectively.

CONCLUSIONS

The disparities in the CRC incidence and mortality trends may reflect socioeconomic inequalities across different population groups in SA. The rapid increase in CRC trends among the Black population group is concerning and requires further investigation and increased efforts for cancer prevention, early screening and diagnosis, as well as better access to cancer treatment.

EHD2 Overexpression Suppresses the Proliferation, Migration, and Invasion in Human Colon Cancer

Background: To investigate how EHD2 influences the development of colon cancer.Methods: Immunohistochemistry of 90 colon cancer tissue specimens were determined the expression of EHD2. The lentivirus-EHD2-transfected colon cancer cells were conducted to evaluate the biological behaviors.Results: EHD2 was closely associated with clinic pathological parameters (p < 0.001). EHD2 upregulation was relative with a longer overall survival. The results of the univariate and multivariate analyses indicated that EHD2 could be an independent prognosis marker. EHD2 overexpression suppressed cell invasion and proliferation, but enhanced cell apoptosis and cell cycle arrest.Conclusions: EHD2 might represent a therapeutic target of colon cancer.IMPACT STATEMENTWhat is already known on this subject? Membrane trafficking is crucial for cell proliferation, differentiation and apoptosis, especially tumorigenesis and development. EHD2 proteins play an important role in the regulation of membrane trafficking in endocytosis. EHD2 has been suggested to participate in the occurrence of some malignancies.What are the new findings? EHD2 could be an independent prognosis marker in colon cancer. EHD2 overexpression suppressed cell invasion and proliferation, but enhanced cell apoptosis and cell cycle arrest in vitro. EHD2 overexpression markedly increased the expression of EMT marker E-cadherin in colon cancer.How might it impact on clinical practice in the foreseeable future? EHD2 overexpression may inhibit tumorigenesis in colon cancer through the modulation of E-cadherin, the critical marker of EMT which is closely related to invasion and distant metastasis of tumor cells.

Cancer health disparities in racial/ethnic minorities in the United States

There are well-established disparities in cancer incidence and outcomes by race/ethnicity that result from the interplay between structural, socioeconomic, socio-environmental, behavioural and biological factors. However, large research studies designed to investigate factors contributing to cancer aetiology and progression have mainly focused on populations of European origin. The limitations in clinicopathological and genetic data, as well as the reduced availability of biospecimens from diverse populations, contribute to the knowledge gap and have the potential to widen cancer health disparities. In this review, we summarise reported disparities and associated factors in the United States of America (USA) for the most common cancers (breast, prostate, lung and colon), and for a subset of other cancers that highlight the complexity of disparities (gastric, liver, pancreas and leukaemia). We focus on populations commonly identified and referred to as racial/ethnic minorities in the USA-African Americans/Blacks, American Indians and Alaska Natives, Asians, Native Hawaiians/other Pacific Islanders and Hispanics/Latinos. We conclude that even though substantial progress has been made in understanding the factors underlying cancer health disparities, marked inequities persist. Additional efforts are needed to include participants from diverse populations in the research of cancer aetiology, biology and treatment. Furthermore, to eliminate cancer health disparities, it will be necessary to facilitate access to, and utilisation of, health services to all individuals, and to address structural inequities, including racism, that disproportionally affect racial/ethnic minorities in the USA.

Similarities in Risk for COVID-19 and Cancer Disparities

Coronavirus disease 2019 (COVID-19) is a novel infectious disease that has spread worldwide. In the United States, COVID-19 disproportionately affects racial and ethnic minorities, particularly African Americans, with an observed 2-fold higher rate for hospitalization and greater than 2-fold higher rate for death as compared with White Americans. The disparity seen with COVID-19 is consistent with patterns of disparities observed for cancer; it is well documented that 5-year survival rates for multiple cancers are lower in African Americans compared with White Americans. Root cause contributions for the disparity overlap between COVID-19 and cancer. While cancer is a genetic disease that is influenced by tissue microenvironment, COVID-19 is an infectious disease that is enabled by cellular expression of angiotensin-converting enzyme 2 receptors. However, socioeconomic disadvantages, level of education, lifestyle factors, health comorbidities, and limited access to medical care appear to fuel underlying risk for both cancer and COVID-19 disparities. In addition to African Americans demonstrating higher risk of acquiring and dying from either disease, they are underrepresented in clinical trials involving cancer or COVID-19. Long-term disparities are present with survivorship from cancer and may be likely with survivorship from COVID-19; both have revealed untoward effects on postdiagnosis economic viability for African Americans. Collaborative strategies that include community engagement, diverse participation in cancer and COVID-19 clinical trials, providing insurance for affected persons who lost employment due to either disease, and supporting safety-net and public hospitals for health care access will be critical to stem these disparities.

African-Americans Are Less Frequently Assessed For Hereditary Colon Cancer

INTRODUCTION

Colorectal cancer (CRC) is the third most common malignancy in the United States and disproportionately affects African-Americans. Approximately 5-10% of CRC results from hereditary cancer syndromes. A detailed family history is recommended as an initial component of cancer risk assessment to help determine initiation, frequency, screening method and genetic counselling referral. This study evaluated the rate of hereditary CRC risk assessment in African-American and white patients.

METHODS

A chart review of all patients referred for CRC screening in a university gastroenterology clinic during a 3 month period was performed. Patient self-described race/ethnicity, gender, age, documentation of multi-generational family medical history (3+ generations) were obtained. Amsterdam II Criteria, Bethesda Criteria and Colorectal Cancer Risk Assessment Tool were used to determine which patients with family histories should receive referrals for genetic counselling. Statistical analysis was performed using Fisher's Exact Test with significance set at p < 0.05. The study was IRB approved.

RESULTS

872 medical records were reviewed, including 452 African-American (276 females, 176 males; mean age 60.2), 263 White (123 females, 140 males; mean age 59.4), 45 Hispanic, and 42 Asian. Multi-generational family history was obtained from 143 (16.4%); 62 African-American (13.7%; 47 females, 15 males), 58 White (22.1%; 37 females, 21 whites), 3 Hispanic (6.7%), and 4 Asian (9.5%). There was a significant difference (p = 0.0050) in the rate of detailed family history in African-Americans and whites. However, African-Americans and Whites similarly qualified for genetic counselling when family history was obtained (p = 0.7915); 58.1% African-Americans (36; 30 females, 6 males) and 50% Whites (29: 19 females, 10 males) qualified for genetic counselling. Overall referral rate to genetic counselling was 16.5% with no significant difference (p = 0.7586) between African-Americans and whites.

CONCLUSIONS

CRC risk assessment with detailed family medical history was inconsistently performed in all patients. There was significantly lower rate of obtaining multi-generational family medical histories in African-Americans. Referrals of all patients for genetic counselling and testing were also insufficient. Appropriate identification of individuals at increased risk for hereditary cancer syndromes, particularly African-Americans, is critical to prevention, early detection, and treatment of CRC and improving disparities in care.

Co-morbid risk factors and NSAID use among white and black Americans that predicts overall survival from diagnosed colon cancer

Black Americans (BA) have higher incidence and higher mortality rates for colorectal cancers (CRC) as compared to White Americans (WA). While there are several identified risk factors associated with the development of CRC and evidence that high levels of adequate screening can reduce differences in incidence for CRC between BA and WA, there remains little data regarding patient co-morbid contributions towards survival once an individual has CRC. Here we set out to identify patient risk factors that influenced overall survival in a cohort of 293 BA and 348 WA with colon cancer. Amid our cohort, we found that patients’ age, tobacco usage, and pre-diagnosed medical conditions such as hypertension and diabetes were associated with shorter overall survival (OS) from colon cancer. We identified pre-diagnosed hypertension and diabetes among BA were responsible for one-third of the colon cancer mortality disparity compared with WA. We also identified long-term regular use of non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, was associated with shorter OS from colon cancer among WA >65 years of age, but not younger WA patients or any aged BA patients. Our results raise the importance of not only treating the colon cancer itself, but also taking into consideration co-morbid medical conditions and NSAID usage to enhance patient OS. Further evaluation regarding adequate treatment of co-morbidities and timing of NSAID continuance after cancer therapy will need to be studied.

Disparities in Cancer Prevention in the COVID-19 Era

Screening for cancer is a proven and recommended approach to prevent deaths from cancer; screening can locate precursor lesions and/or cancer at early stages when it is potentially curable. Racial and ethnic minorities and other medically underserved populations exhibit lower uptake of cancer screening than nonminorities in the United States. The COVID-19 pandemic, which disproportionately affected minority communities, has curtailed preventive services including cancer screening to preserve personal protective equipment and prevent spread of infection. While there is evidence for a rebound from the pandemic-driven reduction in cancer screening nationally, the return may not be even across all populations, with minority population screening that was already behind becoming further behind as a result of the community ravages from COVID-19. Fear of contracting COVID-19, limited access to safety-net clinics, and personal factors like, financial, employment, and transportation issues are concerns that are intensified in medically underserved communities. Prolonged delays in cancer screening will increase cancer in the overall population from pre-COVID-19 trajectories, and elevate the cancer disparity in minority populations. Knowing the overall benefit of cancer screening versus the risk of acquiring COVID-19, utilizing at-home screening tests and keeping the COVID-19-induced delay in screening to a minimum might slow the growth of disparity.

Demographics Predict Stage III/IV Colorectal Cancer in Individuals Under Age 50

GOALS

The goal of this study was to quantify the association between demographic factors and advanced colorectal cancer (CRC) in patients under age 50.

BACKGROUND

CRC incidence in the United States has declined in older individuals but increased in those under age 50 (early-onset). More than 60% of early-onset CRC patients present with advanced disease (stage III/IV), but predictors of stage in this population are poorly defined.

STUDY

We analyzed CRC cases diagnosed between age 20 and 49 in the United States Surveillance, Epidemiology, and End Results (SEER) 18 database during 2004 to 2015. Logistic regression models were fit to assess the impact of age, sex, race, ethnicity, marital status, and cancer site on the probability of advanced disease.

RESULTS

The analysis included 37,044 cases. On multivariable regression, age was inversely associated with advanced disease. Relative to 45 to 49-year-olds, 40 to 44-year-olds had 8% greater odds of having advanced CRC, and 20 to 24-year-olds had 53% greater odds. Asians, blacks, and Pacific Islanders had 10%, 12%, and 45% greater odds of advanced disease compared with whites. Compared with nonpartnered individuals, those with partners had 11% lower odds of advanced CRC. Both right-sided and left-sided colon cancer were more likely to be diagnosed at stage IV compared with rectal cancer.

CONCLUSIONS

Among individuals with early-onset CRC, younger age, Asian, black, or Pacific Islander race, and being nonpartnered were predictors of advanced disease at presentation. Colon cancer was more likely to be diagnosed at stage IV than rectal cancer. Patient characteristics associated with advanced CRC may indicate both differences in tumor biology and disparities in health care access.

Association Between Mycotoxin Exposure and Dietary Habits in Colorectal Cancer Development Among a Polish Population: A Study Protocol

Colorectal cancer (CRC) is one of the most common and lethal types of cancer worldwide. The developing of this disease includes many factors such as genetic, socioeconomic, environmental, and lifestyle factors, and nutrition habits. The aim of the study is the determination of zearalenone and its metabolite level in the biological samples of participants at risk of CRC, in relation to the nutrition data and information on the quality of life dependent on health. In the cohort clinical trial, 150 participants aged between 50 and 65 will be studied. The participants will be assigned into two groups depending on the colonoscopy result. Participants will be tested at dietary intake, quality of life, sleep time and quality, stress level as well as biochemical parameters of the blood. Moreover, in the biological samples, concentration of zearalenone and its metabolites (α-zearalenol and β-zearalenol) as well as the characteristics of gastrointestinal bacterial will be determined, and the end of the trial for both groups and their results will be compared. Taking into account the possible effect of mycotoxins and nutrition habits on the development of cancer, the results obtained may allow the formulation of new nutritional recommendations and reduce the development and occurrence of CRC.

Causes of Socioeconomic Disparities in Colorectal Cancer and Intervention Framework and Strategies

Colorectal cancer (CRC) disproportionately affects people from low socioeconomic backgrounds and some racial minorities. Disparities in CRC incidence and outcomes might result from differences in exposure to risk factors such as unhealthy diet and sedentary lifestyle; limited access to risk-reducing behaviors such as chemoprevention, screening, and follow-up of abnormal test results; or lack of access to high-quality treatment resources. These factors operate at the individual, provider, health system, community, and policy levels to perpetuate CRC disparities. However, CRC disparities can be eliminated. Addressing the complex factors that contribute to development and progression of CRC with multicomponent, adaptive interventions, at multiple levels of the care continuum, can reduce gaps in mortality. These might be addressed with a combination of health care and community-based interventions and policy changes that promote healthy behaviors and ensure access to high-quality and effective measures for CRC prevention, diagnosis, and treatment. Improving resources and coordinating efforts in communities where people of low socioeconomic status live and work would increase access to evidence-based interventions. Research is also needed to understand the role and potential mechanisms by which factors in diet, intestinal microbiome, and/or inflammation contribute to differences in colorectal carcinogenesis. Studies of large cohorts with diverse populations are needed to identify epidemiologic and molecular factors that contribute to CRC development in different populations.