Aspirin is a non-steroidal anti-inflammatory drug (NSAID) that can be used to reduce pain, fever and inflammation.
Researchers assessed the effects of the drug during a 10-year study of 937 people with Lynch syndrome - a genetic disorder that increases the risk of cancers, particularly colon cancer and womb cancer.
Among these patients, the researchers found that being overweight more than doubled the risk of colon cancer, also known as bowel cancer. However, this risk could be reversed with a regular dose of aspirin
The study, published in the Journal of Clinical Oncology, was funded by the UK Medical Research Council, Cancer Research UK, Bayer Pharma and the European Union.
"This is important for people with Lynch Syndrome but affects the rest of us too," states study author Sir John Burn, professor of clinical genetics at Newcastle University in the UK. "Lots of people struggle with their weight and this suggests the extra cancer risk can be canceled by taking an aspirin."
For the study, an international team of researchers from over 43 centers in 16 countries examined the progress of participants with Lynch syndrome who were randomly assigned to either take two aspirins (600 mg) a day for 2 years or a placebo.
The participants were then followed up 10 years later, at which point a total of 55 had developed colon cancers. The researchers found that participants who were obese were 2.75 times as likely to develop this cancer than participants whose weight was normal.
However, among the participants assigned to take two aspirins a day, the researchers found that the risk of colon cancer was the same whether the participants were obese or not.
Every unit of body mass index (BMI) above what is considered healthy increased the risk of colon cancer by 7%. John Mathers, professor of human nutrition at Newcastle University, states that it is surprising that obesity is a driver of cancer even in people with a genetic predisposition to the disease.
"Indeed, the obesity-associated risk was twice as great for people with Lynch Syndrome as for the general population," he adds.
Aspirin could help obese patients who are finding it difficult to lose weight
As the benefits of aspirin appeared to occur before the earliest stages of tumor development, the researchers believe aspirin may affect cells that are predisposed to becoming cancerous over time.
- Aspirin is typically used as a form of pain relief for minor aches and pains and to reduce fever and inflammation
- Aspirin is also prescribed to prevent blood clot formation in patients at high risk of heart attack and stroke
- An estimated 40,000 metric tons of aspirin are consumed annually around the world.
"We may be seeing a mechanism in humans whereby aspirin is encouraging genetically damaged stem cells to undergo programmed cell death," Prof. Burn suggests. "This would have an impact on cancer."
Another possibility is that the aspirin suppresses the inflammatory response that is increased by obesity. There is growing evidence to suggest that an increased inflammatory process is linked with an increased risk of cancer.
While people should try to maintain a healthy weight, Prof. Mathers suggests that aspirin could help patients who are obese and are finding losing weight difficult.
The researchers believe that further research needs to be conducted to both confirm and determine the precise extent of the protection provided by aspirin with respect to high BMI.
Prof. Burn says that before anyone starts to take aspirin on a regular basis, they need to consult their doctor as aspirin can cause a number of stomach complaints, such as ulcers. He adds:
"But if there is a strong family history of cancer, then people may want to weigh up the cost benefits, particularly as these days drugs which block acid production in the stomach are available over the counter."
The researchers now plan to conduct a larger follow-up trial involving 3,000 participants from around the world to test the effects of different doses of aspirin and see if lower doses can offer the same protection.
Aspirin has been found to have anti-cancer properties in the past. Previously, Medical News Today reported on a study that found a daily dose of aspirin could prevent breast cancer development and recurrence in women.