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Areas to be explored: Can "miracle drugs" aspirin limit the development of colorectal cancer (CRC) in East Asians?
In Western countries, the reduction of CRC risk from low-dose aspirin use has been extensively studied and recognized.
According to Western studies, low-dose aspirin use reduces the risk of CRC by 13% to 42%, and some of these studies also believe that the longer you take aspirin, the more significantly the risk of CRC is reduced. In addition, taking low-dose aspirin also reduces the risk of CRC entering advanced stages.
For example, in June this year, researchers at Newcastle University in the United Kingdom led a study published in the Lancet showing that taking 600mg of aspirin per day for 2 years can significantly reduce the risk of CRC in patients with Lynch syndrome, and this protective effect can last for at least 20 years.
At the same time, the report also pointed out that the effective dose of aspirin is still uncertain, and researchers will explore this in subsequent studies.
In recent years, the incidence of CRC in Asia has remained high and rising year by year. This leads one to wonder another question, does aspirin still have this protective effect among East Asians?
Currently, there is less relevant data to support answering this question, limited to data from some medium-sized studies.
To explore the association between low-dose aspirin administration and CRC risk in East Asian populations, the Taiwanese cohort study, which included nearly five million people (n=4710504), was born.
Details and conclusions of the study
This nested case-control study included participants taking aspirin and matched individuals (matched by age, sex) who were taking aspirin in a 2:1 ratio each year from 2002 to 2010, all aged 40 years and older. Information is from Taiwan National Health Insurance (NHI) and Taiwan Cancer Registry (TCR).
In Taiwan, low-dose aspirin is a prescription drug for cardiovascular disease prevention that must be prescribed by a doctor, so the use of the drug is recorded in the NHI database.
Participants were included in the study when they were first prescribed low-dose aspirin. Patients with cancer or contraindications to aspirin before entering the cohort did not meet the admission requirements, and participants with a history of aspirin use prior to 2002 were excluded.
Different dosage forms of aspirin are available, and low-dose aspirin in this study was defined as aspirin with a daily dose of less than 150 mg, and in this study, the most common dosage was 100 mg/day.
The study eventually included 4710504 participants, of whom 2747830 [51.7%] were male; at the time of the study, the median age of the aspirin-using group was 61 [52-71] years and the median age of the non-user group was 59 [51-68]years), and a total of 79,095 participants developed a CRC.
There are three types of exposure to aspirin:
(1) Long-term and currently taking low-dose aspirin (defined as, the most recent dose is 1 year, low dose ≥ 3 years, the number of days taken in the past 3 years accounts for ≥70%)
(2) Occasionally taking low-dose aspirin (i.e., not taking aspirin in the past 1 year, or taking <70% of the days in the past 3 years);)
(3) Did not take aspirin (i.e., did not take low-dose aspirin before the inclusion of studies).
After analyzing the data, the researchers found:
Overall, the corrected post-CRC odds ratio (OR) was 0.89 for long-term users and 0.88 for occasional users compared to participants who did not take low-dose aspirin; among them, participants aged 40-59 had a lower corrected OR — 0.69 for long-term users and 0.64 for occasional users.
The study confirmed that taking low doses of aspirin reduces the risk of CRC.
For people aged 40 years and older, long-term use of low-dose aspirin reduced the risk of CRC by 11% and, if taken occasionally, by 12%.
This effect is more pronounced if the age at which the drug was started is less than 60 years old.
Starting long-term low-dose aspirin between the ages of 40 and 59 reduces the risk of CRC by 30%, while occasionally taking it reduces the risk by 36%.
The study did not support a more significant reduction in the risk of CRC as the duration of aspirin administration was prolonged.
brief summary
This is the largest study to date assessing the risk of low-dose aspirin CRC, with nearly 5 million participants included in the assessment, and 79,095 participants who eventually developed CRC, with a considerable sample size.
The study revealed that overall, for East Asian populations, low-dose aspirin was associated with an 11 percent CRC risk, and the link was even greater if started before the age of 60.
References: Hui-MinDianaLin, PareenVora, MontseSoriano-Gabarró, etal. AssociationBetweenLow-DoseAspirinUseandColorectalCancerIncidenceinTaiwan.JAMANetwOpen.2020;3(11):e2026494.doi:10.1001/jamanetworkopen.2020.26494.