Introduction
Colorectal cancer (CRC) is the third most frequent malignant disease in the world. In some countries with established screening programs, its incidence and mortality have decreased, and survival has improved.
Aims
To obtain reliable data about the epidemiology of CRC in Chile, we analyzed the trends in the last ten years and the influence of observable factors on survival, including a nationwide health program for CRC treatment access (GES program).
Methods
Publicly available data published by the Ministry of Health and National Institute of Statistics were used. Data were obtained from registries of mortality and hospital discharges, making follow-up of the individuals possible. Crude and age-standardized incidence and mortality rates were calculated, and individual survival was studied by constructing Kaplan–Meier curves. Finally, a Cox statistical model was established to estimate the impact of the observable factors.
Results
We found 37,217 newly identified CRC patients between 2008 and 2019 in Chile, corresponding to 103,239 hospital discharges. In the same period, 24,217 people died of CRC. A nearly linear, steady increase in crude incidence, mortality and prevalence was observed. CRC incidence was the lowest in the North of the country, increasing toward the South and reaching a maximum value of 34.6/100,000 inhabitants/year in terms of crude incidence and 20.7/100,000 inhabitants/year in terms of crude mortality in the XII region in 2018. We found that older patients had lower survival rates, as well as men compared to women. Survival was significantly better for patients with private insurance than those under the public insurance system, and the treating hospital also played a significant role in the survival of patients. Patients in the capital region survived longer than those in almost every other part of the country. We found no significant effect on survival associated with the GES program.
Conclusions
We found important inequalities in the survival probabilities for CRC patients in Chile. Survival depends mainly on the type of insurance, access to more complex hospitals, and geographical location; all three factors correlated with socioeconomic status of the population. Our work emphasized the need to create specific programs addressing primary causes to decrease the differences in CRC survival.
Azathioprine (AZA) and 6-mercaptopurine (6-MP) are drugs widely used in the treatment of autoimmune diseases. Among the enzymes involved in the metabolism of AZA and 6-MP are thiopurine methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15). The existence of single nucleotide polymorphisms in the genes that code for these enzymes could decreased enzymatic activity AND lead to severe myelosuppression. The most relevant polymorphism is NUDT15*3 (rs116855232), where the replacement of cytosine for thymine at position 415, which in turn leads to a loss of enzymatic activity. In a previous study, it was identified that together the polymorphisms in the TPMT gene reach an allelic frequency of 3.81%. There is no information regarding the rs116855232 polymorphism in the NUDT15 gene, so this corresponds to the objective of this report. Blood samples from Chilean adult patients with indications for the use of AZA or 6-MP for different pathologies and who had undergone a TPMT gene polymorphism study were retrospectively analyzed. A total of 253 blood samples were analyzed. Of the 253 patients, 47 presented the c.415C>T polymorphism in the NUDT15 gene, 3 being homozygous and 44 heterozygous. Four of the heterozygous patients for NUDT15 also had the *3A variant in the TPMT gene, also heterozygous. The allelic frequency of the minor T allele found (9.88%) was very similar to that found in patients of Asian origin, and much higher than that reported for the European Caucasian or Latin American population.
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