Aspirin and cancer |prevention

A statement from the well-respected US Preventive Services Task Force (USPSTF) in September further reinforced the usefulness of aspirin as a cancer preventive pill for some individuals.

Although still in draft form pending public comments, the new and bold recommendations from the USPSTF state that the taking of a daily dose of aspirin by certain adults in their 50s can not only prevent cardiovascular disease but also colorectal cancer. 

Bowel cancer or colorectal cancer (CRC) is the third leading cause of cancer death in men and women in the US. It affects mainly older adults above the age of 50, peaking at 70 years of age. Importantly, colon cancer can be cured if detected early enough and even avoided through regular screening that includes a colonoscopy procedure from the age of 50.

Aspirin (acetylsalicylic acid) has been widely studied for its multiple pharmacological effects. First synthesised in the late 19th century, aspirin possesses an antipyretic effect (reduces fever), acts as a painkiller (for minor pain) and also has anti-inflammatory properties.

In the early ’70s, its blood thinning effect was discovered and its efficacy in preventing blood clots in people who suffered a heart attack was subsequently recognised. Now aspirin is routinely used for lowering the risk of heart attack and stroke. And with a large number of cardiovascular patients taking daily aspirin, its added anti-cancer properties were incidentally observed, especially on tumours in the gastrointestinal tract. 

Evidence of aspirin’s anti-tumour effects was later consistently demonstrated in long-term trials involving hundreds of thousands of patients. Aspirin reduces the risk of polyps incidence (the benign growths on the inner lining of the colon that may become pre-cancerous and then advance into full-blown colon cancer), lowers the risk of CRC occurrence by about 20 to 40 per cent depending of the patient’s risk level, and limits the spread of secondary tumours (metastasis) in patients with existing CRC. In hereditary bowel cancer, known as Lynch syndrome, aspirin significantly reduces the frequency of malignant colon tumours and is now considered standard therapy for these high-risk patients. 

Many other cancers also appear to be responsive to aspirin’s preventive effects. There is increasing evidence of its help in preventing other malignancies of the gastro-intestinal tract such as oesophagus and stomach cancers as well as lung cancer and, to a lesser extent, prostate cancer. 

Inflammation is known to play an important role in cancer development. Aspirin exerts its anti-inflammatory effects in reducing the production of key substances (known as prostaglandins) that promote inflammation. Aspirin’s anti-cancer properties likely result from its sustained anti-inflammatory effects.

Prescribed at a low daily dosage of 80 to 100mg for cardiovascular prevention aspirin, it needs to be used for at least five years to provide significant benefits in cancer prevention. 

However, even low-dose aspirin has potentially serious side effects and the medicine is certainly not appropriate for every person between the ages of 50 and 59. Side effects include increased risk of ulcers and stomach bleeding, which can occasionally be serious enough to require blood transfusions. Although a growing number of medical experts believe that in the majority of cases, the benefits of aspirin on CRC prevention outweigh its potential risks, aspirin like any medicine needs to be recommended with regard to its benefits / risk ratio for each concerned individual. 

The prevention of bowel cancer also relies on adhering to the proven healthy lifestyle behaviour, that is, no smoking, moderate alcohol consumption, low consumption of red meat, maintenance of healthy body weight and regular exercise. If you are above or approaching 50 years of age, it is definitely worth asking the opinion of your GI specialist when you undergo your next colonoscopy.

 

DR GERARD LALANDE is managing director of CEO-Health, which provides medical referrals for expatriates and customised executive medical check-ups in Thailand. He can be contacted at [email protected].