This video will examine how regular exercise can lower the risk for some cancers, as well as its role in the treatment for cancer patients and survivors. Cancer relates to a group of diseases characterized by uncontrolled growth and spread of abnormal cells. There are over 200 different forms of cancer affecting many cells and tissues in the body. I will focus on the more common types of cancer today. The major modifiable risk factors pertaining to cancer prevention include obesity or fat mass, physical activity and poor dietary habits. A more complete list of risk factors for cancer is shown here and includes age, smoking, sun exposure, infectious diseases, family history and exposure to radiation and chemicals. Regular exercise has been shown to lower the risk for three of the four major forms of cancer. Those sites are breast, prostate and colon cancers. Early detection of cancer greatly improves to treatment options and survival rates. Shown here are the stages of colon cancer. There in the early the stages, the cancer involves just the primary site, but has not spread to nearby tissues. In stage IV cancer, the tumor has grown and has spread to other parts of the body, such as the lungs, making the cancer much more difficult to treat. There are several ways in which regular exercise can reduce the risk for developing certain types of cancers. First, it can retard cancer growth at certain sites by enhancing natural immunity. This will help one's immune system to detect and destroy cancerous cells. Second, regular exercise can increase levels of antioxidants which will reduce the damaging effects from cellular oxidative stress known to promote cancer. Additionally, as discussed in the video on obesity, exercise can reduce total body fat mass which is a risk factor in several types of cancers, such as breast cancer. Finally, exercise can minimize the effects of various hormones and growth factors that can contribute to tumor growth. A prime example is that for IGF-1, or insulin-like growth factor 1. As an example, shown here I have highlighted the main mechanisms cited by medical researchers whereby exercise can reduce key risk factors for primary and secondary breast cancer. In addition to the main mechanisms I have just mentioned related to enhanced immune function, lower fat mass, reduced oxidative stress and growth factors, other potential benefits from regular exercise specific to breast cancer risk are noted. Other examples of the risk lowering effects of exercise, include EGFR colon cancer. The incidence of both of both distal and proximal colon cancers is lower in people who are more physically active than in those who are less physically active. Physical activity is also associated with a decrease risk of colon polyps that may develop into colon cancer. Other potential mechanisms for exercise benefits relate to a reduced exposure time to dietary carcinogens in the colon. As such, risk reduction associated with being physically active, for both breast and colon cancer, can range from approximately 15 to 20%, which compares favorably to the benefits reported for heart disease and diabetes. When examining death rates from all forms of cancer, the relationship between fitness levels and mortality for both men and women is shown here. The more aerobically fit an individual is, the less likely they will die from a cancer related illness. Please notice that even an average fitness level provides a significant protection when compared to sedentary populations. A recent landmark study investigating the relationship between regular physical activity and 26 types of cancers in over 1.4 million adults from many different countries reached the following conclusion. Leisure-time physical activity was associated with lower risk of 13 of the 26 cancers investigated. Healthcare professionals counseling inactive adults should emphasize that most of these associations were evident, regardless of body size or smoking history, supporting broad generalizability of these findings. Thus, even individuals with other risk factors for cancer can see potential risk lowering benefits from exercise. Now that we have discussed exercise and cancer prevention, let's discuss the role of exercise in the treatment for cancer patients and survivors. Cancer patients receiving radiation and chemotherapy treatments frequently suffer from chronic fatigue, loss of muscle mass and strength, reduced stamina, depression and anxiety. Physical activity has been shown to reduce the severity of these side effects, thereby increasing the patient's well-being, and overall quality of life. Physical activity may also lessen the chances of a recurrence and mortality for certain types of cancer, such as breast and colon cancer. Here is one of the many studies demonstrating that regular exercise improves fitness and stamina in cancer patients suffering from severe fatigue. Improvement in these variables can impact other factors such as depression, anxiety and self esteem. Shown here are such outcomes. After 10 weeks of moderate exercise, women recovering from breast cancer surgery reported significantly less depression and anxiety. Further, exercise was something they had control over and made them feel involved in their treatment process, giving them more confidence and peace of mind. The mechanisms responsible for these exercise effects are similar to those already discussed for the prevention of cancer, such as improved immune function, reduced oxidative stress and growth factors as well as the traditional adaptations related to endurance and strength training. Finally, I will conclude today's video by sharing the findings from the very recent, large scale study, comparing the effectiveness of pharmaceutical, psychological and exercise treatments for cancer related fatigue. This meta-analysis investigation examined 113 unique study articles Involving approximately 12,000 cancer patients. The take-home message was that exercise and psychological interventions are effective for improving cancer-related fatigue during and after primary treatment, whereas pharmaceutical interventions are not. Clinicians should prescribe exercise or psychological interventions as first line treatments for cancer related fatigue. I will leave you with a more complete list of the potential benefits of exercise for cancer patients and survivors. In summary, regular physical activity can reduce the risk some of the more common forms of cancer, including breast, prostate and colon cancer. Regular physical activity also improves other risk factors associated with these cancers including obesity, growth factors and oxidative stress. Exercise is also an excellent therapy for cancer patients and survivors, lessening fatigue, depression and anxiety, while increasing stamina, strength, and self-esteem.
