Of these, colorectal cancer is thought to be the most widespread in the Western world; in the United States, this form of malignancy is the second leading cause of cancer-related death.
There are a number of things that we can do to prevent cancer, including leading a healthy lifestyle and having regular screenings if we are at risk. In addition to these, an increasing number of studies have been recently pointing to another prevention strategy: the use of aspirin.
In 2009, an international consensus statement said, "Evidence clearly shows a chemopreventive effect for aspirin and other non-steroidal anti-inflammatory drugs [...] on colorectal cancer and probably other cancer types."
Also, the most recent recommendation statement from the U.S. Preventive Services Task Force "recommends initiating low-dose aspirin use for the primary prevention of [colorectal cancer] in adults aged 50 to 59 [...] willing to take low-dose aspirin daily for at least 10 years."
In this context, Prof. Kelvin Tsoi — from the Chinese University of Hong Kong — and his team set out to examine in more detail the preventive effects of aspirin use on gastrointestinal cancers.
The study spanned 10 years and included more than 600,000 participants. The findings were presented at the 25th United European Gastroenterology Week, held in Barcelona, Spain.
Studying digestive cancer and aspirin use
Prof. Tsoi and his colleagues examined 618,884 participants, 206,295 of whom were aspirin users. Patients taking aspirin were aged 67.5 years, on average, and those who weren't were aged 67.6 years, on average.
Aspirin users had been prescribed the drug for an average duration of 7.7 years, and the median dose prescribed was 80 milligrams.
The team followed the patients' outcomes for up to 14 years, looking for incidences of gastrointestinal cancers, which included colorectal cancer, liver cancer, esophageal cancer, pancreatic cancer, and gastric cancer, as well as non-gastrointestinal ones, which included "breast, bladder, kidney, leukemia, lung, multiple myeloma, or prostate cancers."
Overall, during the follow-up period, 15.9 percent of the patients developed cancer, with lung cancer being the most prevalent.
Digestive cancer risk cut by up to 47 percent
"Long-term use of aspirin showed 24 percent to 47 percent significant reduction on major cancers in the [gastrointestinal] tract," write the authors.
More specifically, aspirin users were 47 percent less likely to have liver and esophageal cancer, 38 percent less likely to have stomach cancer, and 34 percent less likely to have pancreatic cancer.
Additionally, the risk of colorectal cancer among aspirin users was also lowered by 24 percent.
As for non-gastrointestinal cancers, aspirin seemed to significantly reduce the risk of leukemia, lung cancer, and prostate cancer, but it had no significant impact on other cancers (such as breast cancer, bladder cancer, kidney cancer, and multiple myeloma).
Therefore, the study authors conclude that "[l]ong-term use of aspirin can reduce the major types of [gastrointestinal] cancers, but the benefits are limited to some other non-[gastrointestinal] cancers, such as breast and kidney."
"The findings demonstrate that the long-term use of aspirin can reduce the risk of developing many major cancers [...] What should be noted is the significance of the results for cancers within the digestive tract, where the reductions in cancer incidence were all very substantial, especially for liver and esophageal cancer."
Prof. Kelvin Tsoi