Colorectal Cancer Diagnosis and Prevention Strategies

Global Statistics on Colorectal Cancer

In 2012, approximately 1.4 million individuals worldwide received a diagnosis of colorectal cancer. Prevention strategies, particularly screening programs, play a crucial role in decreasing the number of confirmed cases. However, in the United Kingdom, these screening processes only identify about 10% of colorectal cancer cases.

Limitations of Screening Programs

Despite participation in screening programs, the occurrence of post-colonoscopy colorectal cancers remains a concern, underscoring the necessity for additional preventive measures. Pre-cancerous polyps, which can affect the lining of the colon, are often indicators of potential future colorectal cancer.

Aspirin and Omega-3 Fatty Acids in Colorectal Cancer Prevention

Study Background

Research has indicated that a specific free fatty acid (FFA) version of an omega-3 polyunsaturated fatty acid (PUFA), known as C20:5n3 eicosapentaenoic acid (EPA), may improve prognosis for rectal adenoma. Aspirin has also shown potential benefits in preventing colorectal cancer, although guidelines on who should use aspirin and the appropriate dosage remain unclear.

Research Objectives and Methods

Hull and colleagues conducted a study to evaluate the effects of EPA, aspirin, a combination of both, or a placebo on individuals identified as “high risk” for colorectal cancer. This randomized, double-blind controlled trial involved 53 endoscopy units across England, with participants aged 55 to 73 years. They were randomly assigned to receive EPA and aspirin, aspirin and placebo, EPA and placebo, or a double dose of placebo. The EPA dosage consisted of two doses of 2 g 99% EPA-FFA per day, while participants took one 300 mg enteric-coated aspirin tablet daily. A final colonoscopy was performed after 12 months to assess outcomes.

Findings on Adenoma Detection Rates

The study included 709 participants: 179 received EPA, 177 received aspirin, 177 received both treatments, and 176 received the placebo. Results indicated no significant difference in adenoma detection rates across the four groups. However, the combination of EPA and aspirin resulted in a lower incidence of pre-cancerous polyps compared to the other treatments. Notably, EPA influenced different types of lesions variably, and aspirin appeared to reduce the prevalence of conventional pre-cancerous polyps.

Adverse Events and Study Limitations

Participants in the EPA-only group reported a higher incidence of gastrointestinal adverse events, such as nausea, compared to other groups. Serious adverse events were minimal and primarily gastrointestinal or cardiac-related. The study’s limitations included a one-year duration, which may be insufficient for observing significant changes, a higher recruitment of males, and a smaller sample size than originally planned.

Conclusion on Aspirin and EPA Use

Overall Recommendations

Over the course of the 12-month trial, neither EPA nor aspirin demonstrated benefits in adenoma detection rates. However, aspirin users experienced a reduction in the number of pre-cancerous polyps. The effects of EPA and aspirin vary based on polyp types and other factors, with conventional adenomas in the left colorectum showing lower rates in the EPA group and reductions in the right colon attributed to aspirin.

Future Research Directions

Future studies could leverage the findings from this trial to adopt a more personalized medicine approach, identifying which patients might benefit most from using EPA, aspirin, or both, along with other preventive measures.

Reference

Hull MA, et al. Eicosapentaenoic acid and aspirin, alone and in combination, for the prevention of colorectal adenomas (seAFOodPolyp Prevention trial): a multicentre, randomised, double-blind, placebo-controlled, 2 × 2 factorial trial. The Lancet. 2018; 1–12. doi: http://dx.doi.org/10.1016/S0140-6736(18)31775-6.