Colon cancer survivors who engaged in moderate-intensity exercise for six months had fewer circulating tumor cells than non-exercising survivors, according to a 2018 study. The researchers attributed these anticancer effects to mechanical stressors that cancer cells experience in the bloodstream during exercise that drive cells to self-destruct.

Researchers assigned 23 stage I-III colon cancer survivors to engage in either 150 or 300 minutes of moderate-intensity exercise (brisk walking) per week for six months or to continue their normal activities. The researchers measured the participants' circulating tumor cells before and after the intervention.

They found that after six months, both groups of exercisers experienced reductions in their circulating tumor cells, but non-exercisers did not. Exercisers also lost weight and had lower insulin levels.

Circulating tumor cells are cancer cells that separate from the primary cancer site and appear in the bloodstream, where they can migrate to and establish themselves in other parts of the body – a process known as metastasis. Exercise increases blood flow and exerts tremendous mechanical forces on circulating tumor cells, sensitizing them to apoptosis, a cellular self-destruct mechanism.

The findings from this small study suggest that exercise reduces the number of circulating tumor cells in cancer survivors. A larger study showed that stage III colon cancer survivors who exercised were 40 percent less likely to experience a recurrence and 63 percent less likely to die from their cancer compared to non-exercisers. Interestingly, time-restricted eating may help reduce the risk of cancer recurrence, too. Learn more in this episode featuring Dr. Ruth Patterson.

• Read full publication.