Looking for a reason to exercise? How does cancer prevention and treatment sound?
It’s well known that exercise is essential in the treatment of heart disease, diabetes, high blood pressure, and obesity. But now, scientific research is indicating that being physically active is key to a lifestyle that may prevent and even help treat many forms of cancer. Exercise may be a side-effect free alternative to suffering the ravages of cancer.
It’s been known for some time that exercise may play an important role in preventing three types of cancer: colon, breast, and endometrial. More current research swells that number to over 13. Let’s take a look at some of that research and the new study that expands exercise’s potential to stave off cancer.
Take note that most of the research to date does not prove that exercise mitigates cancer risk entirely, but it does indicate a strong associational link.
The Anti-Cancer Potential of Exercise
According to the National Cancer Institute (NCI), “Colon cancer is one of the most extensively studied cancers in relation to physical activity.”
The NCI reports on numerous studies indicating cancer prevention. Here are two of the most significant:
A 2009 meta-analysis found that those who are the most physically active had a 24% lower risk of colon cancer than people who are least active. In 2016, a pooled analysis from 12 U.S. and European prospective, cohort studies found a 16% risk reduction for those most active over those least active.
The NCI reports that “many studies show that physically active women have a lower risk of breast cancer than inactive women.”
For instance, in a 2013 meta-analysis of 31 prospective studies, “the average breast cancer risk reduction…was 12%.”
The NCI states: “Many studies have examined the relationship between physical activity and the risk of endometrial cancer…”
In 2015, a systematic review of physical activity and endometrial cancer (31 studies) found a 20% cancer reduction in those women most physically active.
New Research: A Massive Pooling Study
Most recently, for the first time ever, a massive new study was published online by JAMA Internal Medicine indicating that exercise is associated with lowering the risk of 13 cancers. Twenty-six cancers were studied. The research, a meta-analysis, included 1.4 million subjects, including 186,932 cancers over the course of 11 years. The surprising findings were as follows:
- Esophageal cancer, a 42% lower risk
- Liver cancer, a 27% lower risk
- Lung cancer, a 26% lower risk
- Kidney cancer, a 23% lower risk
- Stomach cancer of the cardia (top portion of the stomach), a 22% lower risk
- Endometrial cancer, a 21% lower risk
- Myeloid leukemia, a 20% lower risk
- Myeloma, a 17% lower risk
- Colon cancer, a 16% lower risk
- Head and neck cancer, a 15% lower risk
- Rectal cancer, a 13% lower risk
- Bladder cancer, a 13% lower risk
- Breast cancer, a 10% lower risk
The study stands as a significant breakthrough in our scientific understanding of the relationship between cancer and exercise.
A study co-author, Alpa V. Patel, Ph.D., from the American Cancer Society, put the results this way:
For years, we’ve had substantial evidence supporting a role for physical activity in three leading cancers: colon, breast, and endometrial cancers, which together account for nearly one in four cancers in the United States. This study linking physical activity to 10 additional cancers shows its impact may be even more relevant, and that physical activity has far reaching value for cancer prevention.
Since nearly 51% of people in the U.S. do not meet minimum physical activity requirements, the authors concluded that their “findings support promoting physical activity as a key component of population-wide cancer prevention and control efforts.”
Caveat: The study also found an increase in the occurrence of prostate cancer (5%) and malignant melanoma (27%). The authors indicated that the increase in melanoma occurred in regions of the U.S. with higher levels of UV radiation. They stressed the importance of taking proper precautions. Prostate cancer increases may be due to screening bias. Healthy men are more likely to have health exams.
Takeaway: Regular aerobic exercise can have a profound impact on your cancer susceptibility.
Exercise and Cancer Survival
Besides lowering the risk of cancer, exercise also shows promise as a means of helping cancer survivors remain cancer-free. The research shows that exercise or overall physical activity can positively affect known aspects of cancer survival.
For a cancer survivor, both reduced physical activity and the effects of cancer treatment can lead to weight gain, which itself is linked to worse cancer survival rates. A 2012 meta-analysis of randomized controlled clinical trials found that physical activity was successful in reducing body weight and BMI in cancer survivors.
Quality of Life
Studies have shown that exercise interventions with cancer survivors had positive effects on quality of life issues such as self-esteem, body image, emotional stability, sleep, anxiety, fatigue, pain, sex, and overall social functioning. Other studies have found that physical activity reduces fatigue and depression and improves physical, social, and mental health.
Recurrence, Progression, and Survival
Physical activity after cancer diagnosis has been linked to better outcomes in specific cancers:
- Breast Cancer: 40 -50% lower risk of cancer recurrence
- Colorectal Cancer: 31% lower death rate
- Prostate Cancer: limited evidence, but one study found a 61% lower death rate in those that exercised at least three hours per week.
What We Still Need to Know
New research is being performed at Memorial Sloan Kettering Cancer Center. Dr. Lee Jones, who directs the Cardio-Oncology Research Program, and his team are attempting to learn how exercise may mitigate the cardiovascular side effects of treatment, as well as prevent cancer and cancer recurrence. It has been historically assumed that cancer patients are unable to participate in exercise programs. Jones’ research is looking at two paradigm shifting areas:
- Mitigating the negative impact of chemotherapy and radiation on cancer patients. Jones is finding that the debilitating effects of cancer therapy can be improved in people who participate in structured exercise programs
- Looking at the potential of exercise as an anti-cancer “drug” that would be prescribed to patients similarly to any other cancer drug.
Christine M. Friedenreich, PhD, an expert on physical activity and cancer risk with Alberta Health Services, says that much more needs to be known about exercise and cancer prevention. Some question for future inquiry include:
- Can resistance training also mitigate cancer susceptibility?
- What is the type, intensity, and amount of exercise needed to reduce cancer risk?
- How physically active at various times of life does one have to be to reduce risk?
- Does exercise benefit those with genetic susceptibility to cancer?
- Does physical activity prevent cancer or does physical inactivity cause cancer?
The hope is that, soon it will be possible to provide exact exercise prescriptions to individuals that can help prevent cancer, decrease recurrence, and foster greater survivability.
Given current scientific knowledge, it may be best to adopt a moderate to rigorous aerobic exercise program to help reduce your chances of developing specific cancers.
If you already have received a cancer diagnosis, speak to your oncologist about the role exercise can play in your recovery.