Global differences in the prevalence of the CpG island methylator phenotype of colorectal cancer.

BACKGROUND: CpG Island Methylator Phenotype (CIMP) is an epigenetic phenotype in CRC characterized by hypermethylation of CpG islands in promoter regions of tumor suppressor genes, leading to their transcriptional silencing and loss of function. While the prevalence of CRC differs across geographical regions, no studies have compared prevalence of CIMP-High phenotype across regions. The purpose of this project was to compare the prevalence of CIMP across geographical regions after adjusting for variations in methodologies to measure CIMP in a meta-analysis. METHODS: We searched PubMed, Medline, and Embase for articles focusing on CIMP published from 2000 to 2018. Two reviewers independently identified 111 articles to be included in final meta-analysis. We classified methods used to quantify CIMP into 4 categories: a) Classical (MINT marker) Panel group b) Weisenberg-Ogino (W-O) group c) Human Methylation Arrays group and d) Miscellaneous group. We compared the prevalence of CIMP across geographical regions after correcting for methodological variations using meta-regression techniques. RESULTS: The pooled prevalence of CIMP-High across all studies was 22% (95% confidence interval:21-24%; I2 = 94.75%). Pooled prevalence of CIMP-H across Asia, Australia, Europe, North America and South America was 22, 21, 21, 27 and 25%, respectively. Meta-regression analysis identified no significant differences in the prevalence of CIMP-H across geographical regions after correction for methodological variations. In exploratory analysis, we observed variations in CIMP-H prevalence across countries. CONCLUSION: Although no differences were found for CIMP-H prevalence across countries, further studies are needed to compare the influence of demographic, lifestyle and environmental factors in relation to the prevalence of CIMP across geographical regions.

Patient-reported Symptom Outcomes and Microsatellite Instability in Patients With Metastatic Colorectal Cancer.

BACKGROUND: The survival of patients with metastatic colorectal cancer (mCRC) is influenced by the genetic and epigenetic changes that might influence the patient experience of symptom burden. Understanding the association of molecular changes with the symptom burden could help clinicians gain insight into the molecular basis of symptom burden and improve treatment tolerance. To date, no studies have compared the patient-reported symptom burden with these molecular subsets among patients with mCRC. PATIENTS AND METHODS: We recruited patients with mCRC that was refractory to ≥ 1 line of therapy who had been enrolled in the Assessment of Targeted Therapies Against Colorectal Cancer trial at The University of Texas MD Anderson Cancer Center. All patients completed a baseline gastrointestinal symptom inventory (MD Anderson Symptom Inventory, gastrointestinal). The symptom burden across key demographic variables and molecular changes, including CRC-associated mutations, microsatellite instability (MSI) status, and the CpG island methylator phenotype (CIMP) were compared using χ2 tests. Association of the symptom burden with overall survival was examined using Cox regression models. RESULTS: Patients with an MSI-high (MSI-H) phenotype reported greater pain (odds ratio [OR], 3.06; 95% confidence interval [CI], 1.61-5.84), fatigue (OR, 2.78; 95% CI, 1.41-5.49), sleep (OR, 2.52; 95% CI, 1.32-4.08); and drowsiness (OR, 2.51; 95% CI, 1.32-4.78) compared with microsatellite stable patients. Patients with an MSI-H phenotype also had greater odds of overall symptom burden (OR, 2.48; 95% CI, 1.29-4.74) compared with microsatellite stable patients. The CIMP-high patients experienced greater odds of pain compared with the CIMP-negative patients (OR, 1.72; 95% CI, 1.06-2.80). A greater overall symptom burden was associated with poor overall survival (hazard ratio, 1.42; 95% CI, 0.98-2.06]), although the difference was not significant (P = .06). CONCLUSION: Correlation of MSI-H-associated tumor features with the symptom burden could help provide a better understanding of underlying mechanisms associated with our findings.

Racial Differences in the Incidence and Survival of Patients With Neuroendocrine Tumors.

OBJECTIVES: The incidence of neuroendocrine tumors (NETs) has been steadily increasing. Racial differences in the incidence and survival are mostly unknown. This study examines the racial differences and the underlying causes. METHODS: We conducted a retrospective, population-based study using datasets from Surveillance, Epidemiology, and End Results (SEER) cancer registry and SEER data linked with Medicare claims (SEER-Medicare). We examined the incidence rates and the effects of patient demographics, clinical characteristics, and socioeconomic factors on survival. RESULTS: Of the 15,786 and 1731 cases from SEER and SEER-Medicare, 1991 and 163 were blacks, respectively. We found that blacks had higher NET incidence for all stages, with the largest difference noted in the local stage (4.3 vs 2.6 per 100,000 in whites). We found worse survival for distant-stage black patients, although they more often had clinical factors typically associated with better prognosis in NETs. However, they were also found to have significant unfavorable differences in socioeconomic and sociodemographic factors. CONCLUSIONS: Blacks have higher incidence of NETs and worse survival compared with other races, especially whites. The influences of neighborhood socioeconomic, sociodemographic, and marital status suggest that social determinants, support mechanisms, and access to health care may be contributing factors.