Aspirin in the chemo-prevention of colorectal neoplasia: an overview

Overview

Colorectal cancer remains a significant cause of illness and death worldwide. Because there has been increasing evidence that long-term use of daily aspirin can decrease a patient’s risk of developing colorectal cancer, an Expert Roundtable was convened to discuss the evidence. They evaluated clinical trials on aspirin’s role in the prevention of cardiovascular disease to determine if aspirin also reduced the risk of colorectal cancer, and observed that aspirin provided this additional benefit. Cancer death (from all types of cancers) was decreased in patients who had taken aspirin for at least four years.

Methodology

The Expert Roundtable performed a systematic review of the evidence indicating aspirin’s preventive benefits on cancer outcomes. They re-evaluated randomized trials designed to evaluate the cardiovascular disease benefits of aspirin, and examined whether research participants taking daily aspirin had a reduced risk of colorectal cancer compared to placebo. They considered several different types of studies and synthesized the results into an assessment about current knowledge of the relationship between aspirin use and cancer.

Results

  • A pooled analysis of four clinical trials concluded that past aspirin use of various durations led to a 24% reduction in the 20-year risk of colorectal cancer.

  • In this same analysis, the benefit increased with longer aspirin use (at least five years) with a 32% reduction in colorectal cancer.

  • Another pooled analysis of eight trials, including a total of 20,000 patients, demonstrated a 21% reduced risk of death from all cancers in patients who had taken aspirin for at least four years.

Conclusions

  • Aspirin reduces the risk of colorectal cancer and cancer mortality. This study confirmed the increasing evidence that daily aspirin can decrease a patient’s risk of developing colorectal cancer, and that this benefit increased with longer aspirin use (>5 years). Aspirin reduced the risk of mortality from all cancers.

  • Aspirin’s potential to prevent cancer should be considered in the decision to prescribe aspirin. Aspirin’s potential to prevent colorectal cancer and cancer mortality should be part of clinical discussions about the benefits and harms of preventive aspirin. In addition, consideration of cancer should expand the population taking aspirin beyond the group identified solely via aspirin’s cardiovascular benefits.