"Aspirin also probably works in ways that we don't quite understand," said Whelan, who heads the Department of Cellular and Molecular Nutrition at the University of Tennessee, Knoxville. "We don't know the mechanism, and it is very difficult to make a blanket public health statement without knowing the mechanism.
"While this backs everything up, I think people should consult their physicians."
The research may not be the last word on aspirin and cancer. Previous studies -- including the large Women's Health Study and the Physicians' Health Study -- have suggested no link between aspirin consumption and reductions in cancer occurrence or cancer-related death. The researchers behind the current study wrote that they excluded these major pieces of research because patients in these studies did not take aspirin on a daily basis.
Even then, the conclusions of the new research do not support a specific dose of aspirin -- so even if there is an effect, those who hope to benefit from it may find themselves at a loss over how much to take.
And although aspirin is a commonly used medicine available over the counter, it is not necessarily safe. People taking aspirin have an increased risk of bleeding, including bleeding in the gastrointestinal tract. This can be very dangerous, and the risk of it happening increases with higher doses.
Most agreed that before medical experts can make any concrete recommendations, further study is needed.
"Because these results are new, it will take time for the broader scientific community to evaluate the data in the context of existing knowledge and to consider whether the clinical guidelines should be changed." said Eric Jacobs, strategic director of Pharmaco-Epidemiology at the American Cancer Society, Inc.
"It is important for patients to follow colon cancer guidelines already in place and get their recommended colon cancer screening tests."
ABC News' Lisa Stark contributed to this report.