October 4, 2023 – Forty-five minutes of vigorous exercise thrice every week may reduce the chance of cancer in patients with Lynch syndrome, a genetic disorder that may result in cancer at a young age.
The Amount of exercise Researchers on the University of Texas MD Anderson Cancer Center have found that the immune system is best capable of eradicate cancer cells. The intervention — 45 minutes of high-intensity cycling three days every week — was specific in nature, said oncologist Eduardo Vilar-Sanchez, MD, PhD, professor of clinical cancer prevention and lead writer of the study.
“We wanted to be very specific with our recommendation,” he said. “People don't follow vague lifestyle advice like 'just exercise.' We wanted to combine a specific biological effect with a very specific intervention.”
The study was small (only 21 people), but it is based on a large amount of evidence linking regular exercise to a reduced risk of cancer, especially colon cancer. But researchers at MD Anderson went a step further and examined How Exercise could reduce the risk of cancer.
Exercise and the immune system
All 21 people in the study suffered from Lynch syndrome and were divided into two groups. One received a 12-month exercise program, the other did not. The scientists checked their cardiovascular and respiratory health and observed immune cells – natural killer cells and CD8+ T cells – in the blood and colon tissue.
“These are the immune cells accountable for attacking foreign entities akin to cancer cells,” Vilar-Sanchez said, “they usually were more lively within the participants who exercised.”
The level of the inflammatory marker prostaglandin E2 (PGE2) also fell in the participants in the training group. This decline was closely linked to the increase in immune cells. Both changes indicate a stronger immune response.
The researchers assume that the changes are related to a strengthening of the body's own “immune surveillance system” in the search for and elimination of harmful cells otherwise become cancerous.
Building on previous research
Science already provides a lot of evidence that regular exercise can help prevent cancer. Systematic review 2019 More than 45 studies and several million people found strong evidence that exercise can reduce the risk of several types of cancer – including bladder, breast, colon and stomach cancer – by up to 20%.
However, the MD Anderson study is the first to show a link between exercise and changes in immune biomarkers, the researchers said. “It's one thing to know the epidemiological context, but it's another thing to know the biological basis,” says Xavier Llor, MD, PhD, director of the GI Cancer Prevention Program at Yale Cancer Center and professor of medicine at Yale School of Medicine. (Llor was not involved in the study.)
Two previous studies looked at exercise and inflammatory markers in healthy people and in those with a history of colon polyps, but neither study produced meaningful results. The success of this new study may be due to the more intense exercise or additional colon tissue samples. But technological advances also now allow for more sensitive measurements, the researchers said.
What you should know
Vilar-Sanchez is hesitant to extend the study results beyond people with Lynch syndrome, but is optimistic that they could apply to the general population.
Llor agrees: “Through some of these mechanisms, exercise may protect against other types of cancer,” he said.
According to the American Cancer Society, more than 15% of all cancer deaths (excluding tobacco-related cancers) in the United States are due to lifestyle factors, including physical inactivity, obesity, alcohol consumption and poor diet. It recommends 150 to 300 minutes of moderately intense exercise per week to scale back the chance of cancer. Study participants showed a major immune response to 135 minutes of high-intensity exercise per week.
“The public should know that engaging in any form of physical activity somehow have implications for cancer prevention,” said Vilar-Sanchez.