Racial disparities and socioeconomic status in the incidence of colorectal cancer in Arizona

Statistical methods for measuring trends in colorectal cancer incidence in registries: A systematic review

Background

Monitoring cancer trends in a population is essential for tracking the disease’s burden, allocating resources, and informing public health policies. This review describes variations in commonly employed methods to estimate colorectal cancer (CRC) incidence trends.

Methods

We performed a systematic literature search in four databases to identify population-based studies reporting CRC incidence trends, published between January 2010 and May 2020. We extracted and described data on methods to estimate trends and assess model validity, and the software used.

Results

This review included 145 articles based on studies conducted in five continents. The majority (93%) presented visual summaries of trends combined with absolute, relative, or annual change estimates. Fourteen (10%) articles exclusively calculated the relative change in incidence over a given time interval, presented as the percentage of change in rates. Joinpoint regression analysis was the most commonly used method for assessing incidence trends (n= 65, 45%), providing estimates of the annual percentage change (APC) in rates. Nineteen (13%) studies performed Poisson regression and 18 (12%) linear regression analysis. Age-period-cohort modeling- a type of generalized linear models- was conducted in 18 (12%) studies. Thirty-nine (37%) of the studies modeling incidence trends (n=104, 72%) indicated the method used to evaluate model fitness. The joinpoint program (52%) was the statistical software most commonly used.

Conclusion

This review identified variation in the calculation of CRC incidence trends and inadequate reporting of model fit statistics. Our findings highlight the need for increasing clarity and transparency in reporting methods to facilitate interpretation, reproduction, and comparison with findings from previous studies.

Racial Disparities in Colorectal Cancer Care for Black Patients: Barriers and Solutions

Racial disparities in colorectal cancer for Black patients have led to a significant mortality difference when compared to White patients, a gap which has remained to this day. These differences have been linked to poorer quality insurance and socioeconomic status in addition to lower access to high-quality health care resources, which are emblematic of systemic racial inequities. Disparities impact nearly every point along the colorectal cancer care continuum and include barriers to screening, surgical care, oncologic care, and surveillance. These critical faults are the driving forces behind the mortality difference Black patients face. Health care systems should strive to correct these disparities through both cultural competency at the provider level and public policy change at the national level.

A systematic review of methods to estimate colorectal cancer incidence using population-based cancer registries

Background

Epidemiological studies of incidence play an essential role in quantifying disease burden, resource planning, and informing public health policies. A variety of measures for estimating cancer incidence have been used. Appropriate reporting of incidence calculations is essential to enable clear interpretation. This review uses colorectal cancer (CRC) as an exemplar to summarize and describe variation in commonly employed incidence measures and evaluate the quality of reporting incidence methods.

Methods

We searched four databases for CRC incidence studies published between January 2010 and May 2020. Two independent reviewers screened all titles and abstracts. Eligible studies were population-based cancer registry studies evaluating CRC incidence. We extracted data on study characteristics and author-defined criteria for assessing the quality of reporting incidence. We used descriptive statistics to summarize the information.

Results

This review retrieved 165 relevant articles. The age-standardized incidence rate (ASR) (80%) was the most commonly reported incidence measure, and the 2000 U.S. standard population the most commonly used reference population (39%). Slightly more than half (54%) of the studies reported CRC incidence stratified by anatomical site. The quality of reporting incidence methods was suboptimal. Of all included studies: 45 (27%) failed to report the classification system used to define CRC; 63 (38%) did not report CRC codes; and only 20 (12%) documented excluding certain CRC cases from the numerator. Concerning the denominator estimation: 61% of studies failed to state the source of population data; 24 (15%) indicated census years; 10 (6%) reported the method used to estimate yearly population counts; and only 5 (3%) explicitly explained the population size estimation procedure to calculate the overall average incidence rate. Thirty-three (20%) studies reported the confidence interval for incidence, and only 7 (4%) documented methods for dealing with missing data.

Conclusion

This review identified variations in incidence calculation and inadequate reporting of methods. We outlined recommendations to optimize incidence estimation and reporting practices. There is a need to establish clear guidelines for incidence reporting to facilitate assessment of the validity and interpretation of reported incidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01632-7.

Socioeconomic inequalities in colorectal cancer incidence in Canada: trends over two decades

PURPOSE

Colorectal cancer is the third most commonly diagnosed cancer in Canada. This study aimed to measure and examine trends in socioeconomic inequalities in the incidence of colorectal cancer in Canada.

METHODS

This study is a time trend ecological study based on Canadian Census Division level data constructed from the Canadian Cancer Registry, Canadian Census of Population, and National Household Survey. We assessed trends in income and education inequalities in colorectal cancer incidence in Canada from 1992 to 2010. The age-standardized Concentration index ([Formula: see text]), which measures inequality across all socioeconomic groups, was used to quantify socioeconomic inequalities in colorectal cancer incidence in Canada.

RESULTS

The average crude colorectal cancer incidence was found to be 61.52 per 100,000 population over the study period, with males having a higher incidence rate than females (males: 66.98; females: 56.25 per 100,000 population). The crude incidence increased over time and varied by province. The age-standardized C indicated a higher concentration of colorectal cancer incidence among lower income and less-educated neighborhoods in Canada. Income and education inequalities increased over time among males.

CONCLUSION

The concentration of colorectal cancer incidence in low socioeconomic neighborhoods in Canada has implications for primary prevention and screening.

Incidence and prognosis of undifferentiated cancers of the digestive system: a population-based cohort study

Background

Cases of undifferentiated cancers of the digestive system (UCDS) are occasionally encountered in clinical practice; however, no large-scale studies have described their characteristics. This study aimed to investigate the incidence, prognosis, and treatment strategies of UCDS.

Methods

We used the data from the Surveillance, Epidemiology, and End Results database to evaluate clinical characteristics in UCDS patients. A cohort of 1,372 patients was included to estimate UCDS incidence; another cohort of 1,816 patients was followed up until December 31, 2017 to evaluate treatment and prognosis. The incidence, trends, treatments, overall survival, and cause-specific survival were assessed.

Results

The estimated incidence of UCDS was 0.136 per 100,000 people-years [95% confidence interval (CI): 0.129-0.143] from 1975 to 2016 with respect to sex, age, year of diagnosis, race, region, site, income, and education. The age-adjusted rates of UCDS dropped from 0.567 per 100,000 people-years in 1978 to 0.031 per 100,000 people-years in 2016. The rates of surgery, beam radiation, and chemotherapy in patients with UCDS were 37.3%, 17.3%, and 30.7%, respectively. Overall, the 5-year cause-specific survival rate was 18%, with a median cause-specific survival of 4 months. Patient prognosis improved significantly over the decades; stage, site, year of diagnosis, surgery, beam radiation, and chemotherapy were independent prognostic factors for UCDS mortality.

Conclusions

The incidence of UCDS has decreased in the United States over the past 40 years. Patients benefited from surgery, beam radiation, and chemotherapy. The survival of patients with UCDS has improved. Further research on developing decision-making recommendations for UCDS treatment is crucial.

Trends in Sociodemographic Disparities in Colorectal Cancer Staging and Survival: A SEER-Medicare Analysis

INTRODUCTION

Race, ethnicity, and socioeconomic status are known to influence staging and survival in colorectal cancer (CRC). It is unclear how these relationships are affected by geographic factors and changes in insurance coverage for CRC screening. We examined the temporal trends in the association between sociodemographic and geographic factors and staging and survival among Medicare beneficiaries.

METHODS

We identified patients 65 years or older with CRC using the 1991-2010 Surveillance, Epidemiology, and End Results-Medicare database and extracted area-level sociogeographic data. We constructed multinomial logistic regression models and the Cox proportional hazards models to assess factors associated with CRC stage and survival in 4 periods with evolving reimbursement and screening practices: (i) 1991-1997, (ii) 1998-June 2001, (iii) July 2001-2005, and (iv) 2006-2010.

RESULTS

We observed 327,504 cases and 102,421 CRC deaths. Blacks were 24%-39% more likely to present with distant disease than whites. High-income areas had 7%-12% reduction in distant disease. Compared with whites, blacks had 16%-21% increased mortality, Asians had 32% lower mortality from 1991 to 1997 but only 13% lower mortality from 2006 to 2010, and Hispanics had 20% reduced mortality only from 1991 to 1997. High-education areas had 9%-12% lower mortality, and high-income areas had 5%-6% lower mortality after Medicare began coverage for screening colonoscopy. No consistent temporal trends were observed for the associations between geographic factors and CRC survival.

DISCUSSION

Disparities in CRC staging and survival persisted over time for blacks and residents from areas of low socioeconomic status. Over time, staging and survival benefits have decreased for Asians and disappeared for Hispanics.

Decreased Use of Sphincter-Preserving Procedures Among African Americans with Rectal Cancer

BACKGROUND

Improved multimodality rectal cancer treatment has increased the use of sphincter-preserving surgery. This study sought to determine whether African American (AA) patients with rectal cancer receive sphincter-preserving surgery at the same rate as non-AA patients.

METHODS

The study used the Nationwide Inpatient Sample for years 1998-2012 to compare AA and non-AA patients with rectal cancer undergoing low anterior resection or abdominoperineal resection. The logistic regression model was used to adjust for age, gender, admission type, Elixhauser comorbidity index, and hospital factors such as size, location (urban vs.rural), teaching status, and procedure volume.

RESULTS

The search identified 22,697 patients, 1600 of whom were identified as AA. After adjustment for age and gender, the analysis showed that AA patients were less likely to undergo sphincter-preserving surgery than non-AA patients [odds ratio (OR) 0.70; 95% confidence interval (CI) 0.63-0.78; p < 0.0001). After further adjustment for the Elixhauser comorbidity index, admission type, hospital-specific factors, and insurance status, the analysis showed that AA patients still were less likely to undergo sphincter-preserving surgery (OR 0.78; 95% CI 0.70-0.87; p < 0.0001). Although the proportion of non-AA patients undergoing sphincter-preserving surgery increased during the study period (p = 0.0003), this trend was not significant for the AA patients (p = 0.13).

CONCLUSION

In this data analysis, the AA patients with rectal cancer had lower rates of sphincter-preserving surgery than the non-AA patients, even after adjustment for patient- and hospital-specific factors. Further work is required to elucidate why. Eliminating racial disparities in rectal cancer treatment should continue to be a priority for the surgical community.

The genetics and molecular biology of colonic neoplasia: practical implications for the clinician

PURPOSE OF REVIEW

Despite the large investment of resources from screening, the fact that colorectal cancer remains the second leading cause of cancer deaths among Americans underscores the need for alternative strategies. Thus, a major clinical and research imperative is personalize clinical care, while focusing on risk stratification for screening, surveillance, chemoprevention, and therapeutic intervention.

RECENT FINDINGS

A complicating factor that colorectal cancer is biologically heterogeneous for at least four consensus molecular subtypes presents clear challenges for developing robust molecular biomarkers.

SUMMARY

The purpose of the review is to discuss the genetics and molecular biology of colonic neoplasia, high and low penetrance, and racial disparities in colonic neoplasia. Finally, we put forth the emerging concept of greater genomic landscape and the idea of chromatin protection therapy as a novel adjuvant to chemotherapy.