Exercise linked to decreased colon cancer risk

The Journal of Physiology published research that highlights the link between exercise and decreased tumour growth in colon cancer.

colon cancer

As time passes by, the baby-boomer generation increases in age and consequently, the global population’s median age also increases. With older age, comes a higher risk of chronic diseases. Cancer, specifically colon cancer, is the third most commonly diagnosed malignancy, and the fourth leading cause of colorectal death worldwide.

An article in the BMJ Journal states that colon cancer is considered a clear marker of countries undergoing societal and economic changes, as the rates of cancer are seen to increase rapidly to statistics seen only in high-income countries. In such countries, education of healthy behaviours, including regular regimented exercise, is always recommended but rarely fully implemented throughout the population.

The Journal of Physiology recently published a study that focused on the effects of physical exercise on colon cancer mortality. Male colon cancer survivors over 40 years old whose last radiation therapy, chemotherapy, or surgical treatment was less than one month ago, were selected. They then completed an acute or chronic high-intensity interval exercise (HIIE) session. Each session lasted roughly 38 minutes and was to be completed three times a week for four weeks.

Serum blood samples were collected at baseline and after the HIIE intervention. In the acute HIIE group, a sample was collected at the start of the study (fasted), immediately after the HIIE session, and again 120 minutes after the session. In the chronic HIIE group, the fasted blood sample was collected three to seven days prior to the session as a pre-intervention sample, and after the HIIE session. The samples were obtained at the same time of the day for both collections. Researchers then compared and analyzed the samples to study the growth of colon cancer cells.

Exercise may play a role in suppressing colon cancer growth

Upon analysis, the researchers found several systemic changes following the acute HIIE session. There was a transient promotion of systemic cytokine concentrations, which was believed to be linked to the suppression of the colon cancer cell proliferation. However, this promotion tapered off two hours after exercise, thus concluding that regular exercise would provide repeated acute benefits that would may make the body less conducive to colon cancer growth. Samples from the chronic HIIE intervention did not yield the same results.

Surprisingly, there was no increase in cellular reduction. Researchers linked this to a lack of change in specific markers (IGF1 and insulin), which have the potential to prevent tumour initiation of intracellular signalling and improved insulin resistance.

As stated in the press release from lead researcher James Devin, “We have shown that exercise may play a role in inhibiting the growth of colon cancer cells. After an acute bout of HIIT there were specific increases in inflammation immediately after exercise, which are hypothesized to be involved in reducing the number of cancer cells”. As the first of its kind to show the positive acute changes to colon cancer tumour growth immediately after an HIIE session, the study supported others that also came to similar conclusions in other types of cancer.

Several limitations were noted with this study. The findings were limited by a small number of participants, due to the nature of it being a pilot study. Next, other extraneous factors were not accounted for and may have contributed to the reductions in colon cancer cell growth. Lastly, the lack of a control group was considered as a limitation as results could not be compared to.

In all, there are a plethora of positive benefits already documented and researched with regular regimented exercise. Nevertheless, this study presents findings that give promise to future health and medical interventions that can fight against the global chronic disease of cancer.

Written by Lacey Hizartzidis, PhD

References:

  1. Arnold, M., Sierra, M. S., Laversanne, M., Soerjomataram, I., Jemal, A., & Bray, F. (2017, April 01). Global patterns and trends in colorectal cancer incidence and mortality. Retrieved from https://gut.bmj.com/content/66/4/683
  2. Devin, J. L., Hill, M. M., Mourtzakis, M., Quadrilatero, J., Jenkins, D. G., & Skinner, T. L. (2019). Acute high intensity interval exercise reduces colon cancer cell growth. The Journal of Physiology. doi:10.1113/jp277648
  3. Turan, J. (2019, February 27). Colon cancer growth reduced by exercise. Retrieved from https://www.eurekalert.org/pub_releases/2019-02/tps-ccg022619.php