Incidence and mortality from colon and rectal cancer in Midwestern Brazil

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.

The value of miR-510 in the prognosis and development of colon cancer

Purpose

Colon cancer is one of the malignant tumors that threatens human health. miR-510 was demonstrated to play roles in the progression of various cancers; its dysregulation was speculated to be associated with the development of colon cancer.

Methods

One hundred and thirteen colon cancer patients participated in this research. With the help of RT-qPCR, the expression of miR-510 in collected tissues and cultured cells was analyzed. The association between miR-510 expression level and clinical features and prognosis of patients was evaluated. Moreover, the effects of miR-510 on cell proliferation, migration, and invasion of colon cancer were assessed by CCK8 and Transwell assay.

Results

miR-510 significantly upregulated in colon cancer tissues and cell lines relative to the adjacent normal tissues and colonic cells. The expression of miR-510 was significantly associated with the TNM stage and poor prognosis of patients, indicating miR-510 was involved in the disease progression and clinical prognosis of colon cancer. Additionally, the upregulation of miR-510 significantly promoted cell proliferation, migration, and invasion of colon cancer, while its knockdown significantly inhibited these cellular processes. SRCIN 1 was the direct target of miR-510 during its promoted effect on the development of colon cancer.

Conclusion

The upregulation of miR-510 acts as an independent prognostic indicator and a tumor promoter by targeting SRCIN 1 in colon cancer, which provides novel therapeutic strategies for colon cancer.

Net survival for colorectal cancer in Cuiabá and Várzea Grande (state of Mato Grosso), Brazil

In studies of cancer survival, Population-Based Cancer Registries (PBCRs) can provide an overview of the disease for places that have this source of information available. In Brazil, PBCR is officially available in 22 state capitals and 8 cities in the interior of the country. PBCR data from Cuiabá and Várzea Grande, state of Mato Grosso, in Midwestern Brazil, were used to estimate the survival rate of colon (C18), rectosigmoid junction (C19) and rectum (C20) cancer cases diagnosed in 2000-2009 according to the International Classification of Diseases, 10th Revision. Five-year survival rate was estimated by the unbiased and consistent net survival estimator, which is used in the country estimates of the global surveillance of cancer survival programme CONCORD Group, for all cases, and also by sex, age group, diagnosis period and place of residence. The probability of death and the number of years of life lost to illness were also estimated. The estimated standardised 5-year survival rate for colorectal cancer was 45.46% (95% CI: 43.09%-47.96%) in the cities of Cuiabá and Várzea Grande. There was no difference between the curves when the survival rate was assessed by diagnostic period (2000-2004 and 2005-2009), sex, age group or city of residence. The gross 5-year probability of death from the disease was 51.2%, accounting for 6.4% of the gross probability of death from other causes, with 2.07 being the years of life lost to illness. The results obtained for Cuiabá and Várzea Grande are compatible with survival rates estimated for Brazil in the CONCORD study, but demonstrate the need to identify reasons why we continue to have low survival rates when compared to most countries involved in the global study mentioned. The results may reflect late diagnosis, difficult access and delays in starting treatment.

Colorectal cancer mortality in Mato Grosso, Brazil: Spatiotemporal trends

Mortality due to colorectal cancer is increasing in Brazil, but an organised approach to screening and prevention is lacking. Considering the importance of this disease, the present study examines recent mortality trends of colorectal cancer mortality in the meso- and microregions in the state of Mato Grosso with the objective of analysing spatiotemporal trends to help guide the allocation of health services related to this type of cancer. Mortality data from the Brazilian national public health system from 1996 to 2015 were analysed investigating spatiotemporal trends using Conditional Autoregressive (CAR) models, a class of Bayesian hierarchical models that rely on Markov Chain Monte Carlo (MCMC) simulations. Convergence issues arose with several types of CAR models, but notably not with the linear variant, which models the mortality within each spatial region as a linear function of time. Men and women of all ages displayed higher and increasing mortality rates in the Cuiabá and Rondonópolis microregions. Additional regions of increasing mortality were found for specific age and gender strata. It was concluded that spatiotemporal modelling is a useful tool for the characterisation of diseases, including cancer, which are influenced by several factors and need to be monitored over space and time. The combination of spatial and temporal analyses of mortality shown in this paper unveils important information regarding the small areas dynamics, which may guide discussions, regulation and application of decentralised public health policies.