From the Guidelines
Regular aspirin use may help reduce the risk of bowel cancer, with a 20-40% reduction in colorectal cancer risk when taken at a low dose (75-100mg daily) over a long period (at least 5-10 years). This protective effect appears to be most significant when started in middle age (around 50-60 years old) and continued for at least a decade, as shown in a study published in 2021 1. Aspirin works by inhibiting cyclooxygenase enzymes, reducing inflammation and potentially slowing the growth of precancerous polyps in the colon.
The benefits of aspirin in reducing colorectal cancer risk are supported by several studies, including a pooled analysis of 4 trials (n = 69,535) that found a 40% reduction in CRC incidence 10-19 years after aspirin initiation (RR, 0.60; 0.47-0.76) 1. Another study found that aspirin reduced 20-year cumulative CRC incidence by 24% (HR, 0.76; 95% CI, 0.63-0.94) 1.
However, aspirin therapy carries risks, including gastrointestinal bleeding and hemorrhagic stroke. Therefore, it's not recommended for everyone as primary prevention. The decision to take aspirin should be individualized based on your personal risk factors for both colorectal cancer and bleeding complications. Those with a family history of colorectal cancer, certain genetic syndromes, or previous polyps may benefit more. Before starting aspirin therapy, consult with your healthcare provider to weigh the potential benefits against risks based on your specific health profile, as recommended by the US Preventive Services Task Force in 2016 1.
Some key points to consider when deciding whether to take aspirin for bowel cancer prevention include:
- The dose and duration of aspirin therapy: low-dose aspirin (75-100mg daily) taken for at least 5-10 years appears to be most beneficial
- Individual risk factors: family history, genetic syndromes, previous polyps, and bleeding complications should be taken into account
- Age: middle age (around 50-60 years old) appears to be the most beneficial time to start aspirin therapy
- Consultation with a healthcare provider: to weigh the potential benefits against risks based on your specific health profile.
From the Research
Aspirin and Bowel Cancer: Benefits and Risks
- Regular low-dose aspirin use has been shown to reduce the long-term incidence and risk of colorectal cancer deaths by approximately 20% 2.
- However, there are also risks to aspirin use, mainly gastrointestinal bleeding and haemorrhagic stroke 2, 3.
- The benefits of aspirin in preventing colorectal cancer may outweigh the risks for individuals at increased risk of developing cancer 4, 5.
Mechanisms of Action and Optimal Dose
- The exact mechanisms by which aspirin exerts its anticancer effects are not fully understood, but may involve the inhibition of platelet activation 3.
- There is uncertainty about the optimal dose and duration of aspirin for colorectal cancer prevention 4, 5.
- Large-scale meta-analyses are quantifying the cost-benefit ratio of aspirin use in the general population 4.
Clinical Practice and Future Directions
- Clinical guidelines for prophylactic aspirin use currently only consider the cardiovascular benefits of aspirin, but may need to be revised to take into account the potential benefits for colorectal cancer prevention 3.
- International trials are underway to assess the optimal dose of aspirin in high-risk individuals and the role of aspirin as an adjuvant in those who present with a malignancy 4.
- Further research is needed to understand the molecular mechanisms of aspirin's anticancer effects and to develop personalized approaches to colorectal cancer prevention 5, 6.