Exercise and the 14 Cancer Types Whose Risk It Reduces

This article highlights research and reviews revealing the relationship between physical activity, that is exercise, and cancer risk. Exercise also reduces treatment side effects and may help recovery after chemotherapy, radiotherapy and surgery.

Breast cancer survivors

A study in the Journal of Clinical Oncology stated that increasing strength training and aerobic exercise significantly reduced joint pain (arthralgia) in breast cancer survivors treated with aromatase inhibitors. Researchers noted reduced pain after only 3 months, but women continuing exercise for 12 months had substantial benefit (30% reduction in joint pain). These activities included 150 minutes of aerobic exercise weekly and supervised strength training twice weekly. Baseline worst pain scores were 5.6 in women exercising and 5.9 in those devoting little time to exercise. In active women, worst pain decreased an average of 1.6 points (29%), compared with 0.2 in less active women.

Breast cancer risk

“Biomarkers and Prevention,” one recent study published in Cancer Epidemiology, showed an association between regular light exercise and reduced invasive breast cancer risk in postmenopausal women. Over 4 years, women walking 4 hours weekly had a 10% lower disease risk than those exercising less during the same period. Researchers emphasized regular exercise: over 5 - 9 years, among women exercising more than 12 hours weekly, those reducing exercise had significantly increased breast cancer risk compared with those continuing regularly.

Prostate cancer

A study in Oncology Nursing Forum showed that supervised group exercise improved physical and mental health in prostate cancer patients and provided much-needed emotional and social support. Researchers interviewed 12 patients participating in a physiologist-led group program. Joining a prostate cancer-specific exercise group helped break down prejudices preventing patients from seeking health support. Researchers concluded group exercise programs should be included in supportive care for prostate cancer patients.

Lung cancer

A study in the Journal of Thoracic Oncology concluded that exercise and physical activity should be among treatment options for lung cancer patients because they reduce symptoms, improve exercise tolerance and quality of life, and reduce postoperative complications and hospital stays. Researchers found that most patients wanted guidance from physicians about physical activity and exercise and encouraged them to recommend exercise before, during and after diagnosis and treatment.

Ovarian cancer risk

Although evidence linking physical activity and ovarian cancer risk is insufficient, researchers continue studying this group. A review in Gynecologic Oncology concluded that physicians should encourage physical activity in ovarian cancer patients despite insufficient evidence. It included 26 studies finding a protective effect between epithelial ovarian cancer risk and physical activity. Most showed 30-60% lower risk in highly active women, but cohort studies showed no significant association.

Colorectal cancer

A Journal of Clinical Oncology study examined physical activity and sedentary leisure time in patients diagnosed with colorectal cancer. Participants answered questionnaires on physical activity and leisure time before and after diagnosis. Those undertaking 8.75 or more metabolic equivalent (MET)-hours weekly (approximately 150 dk. of walking weekly) had lower all-cause mortality than those undertaking less than 3.5 MET-hours weekly. Spending 6 or more leisure hours daily sitting also increased all-cause mortality compared with sitting less than 3 hours.

Stomach cancer risk

A study in the British Journal of Sports Medicine investigated whether physical activity was associated with stomach cancer risk. Using 7 prospective cohort and 4 case-control studies, it found a modest association between adequate physical activity and stomach cancer risk. Other factors, such as smoking and cancer subtype, weakened this association.

Leukemia

An Integrative Cancer Therapies study tested feasibility of an in-hospital exercise program for acute leukemia patients receiving chemotherapy. It included 10 patients, assessing weight, body composition, cardiorespiratory endurance, weakness, depression and quality of life at baseline and treatment end. Aerobic and strength exercises were performed twice daily for 30 dk, 3 times weekly. Cardiorespiratory endurance improved significantly, while weakness and depression scores decreased.

Head and neck cancers

A study evaluated exercise’s effects on functional capacity and quality of life in 48 head and neck cancer patients receiving chemoradiotherapy. Patients were divided into exercise and control groups. The exercise group followed a supervised program for 6 weeks, while controls received physical activity education. The study evaluated self-reported health and pain scales using a 6-minute walking distance. After 6 weeks, the exercise group’s 6-minute walking distance improved by 42 m, while controls declined by 96 m. Mental status also improved in the exercise group, while both physical and mental status declined in controls.

Pancreatic cancer

In a single-case study, researchers evaluated effectiveness and safety in a 49-year-old patient with stage-IIb pancreatic cancer receiving adjuvant treatment, using a supervised 6-month exercise program. It involved endurance and aerobic exercises twice weekly. Over 6 months, the patient tolerated the program well and achieved 73% attendance. Improvements in physical capacity and function, disease-related quality of life, cancer-related weakness, sleep quality and psychological distress were found at both 3 and 6 months.

Multiple myeloma

An Australian study investigated benefits and barriers to physical activity in patients recently treated for multiple myeloma. Benefits (psychological and social) and barriers (overcoming treatment symptoms and side effects, and low motivation) were assessed through interviews. Although all participants engaged in light and moderate activity such as walking and gardening, women reported benefits more than men. Patients treated with autologous stem cell transplantation also reported benefit, while those receiving other treatments such as chemotherapy and radiotherapy faced more pain barriers.

Kidney cancer risk

A study in Medicine & Science in Sports & Exercise found that walking and running may reduce kidney cancer risk independently of other known risk factors. After age and sex adjustment, weekly running or walking reduced risk by 1.9% per metabolic equivalent (MET)-hour. Compared with below-recommended running or walking (< 7.5 MET-hours weekly), risk fell 61% at recommended activity, at 1-2 times the recommended level by 67%, and at 2 or more than 2 times the level by 76.3%.

Brain cancer risk

Data from The National Runners’ and Walkers’ Health Studies were used to examine exercise’s effect on brain cancer mortality. After adjustment for age, sex, race, education and so on, brain cancer mortality risk decreased in those exercising 1.8 - 3.5 metabolic equivalent (MET)-hours daily by 43.2%, and in those exercising ≥ 3.6 MET-hours daily by 39.8% (compared with < 1.8 MET-hours daily). Researchers concluded that energy expended walking and running was associated with lower brain cancer mortality risk.

Endometrial (uterine) cancer risk

The American Institute for Cancer Research and The World Cancer Research Fund International published findings showing that approximately 60% of endometrial cancers in America could be prevented through regular exercise and maintaining healthy weight. Risk doubles in obese women because excess body fat is a major risk factor. Exercising at least 30dk daily and maintaining a healthy body mass index reduced endometrial cancer rates by 59%. Exercise may also prevent recurrence.

Sarcoma

A Journal of Sports Science & Medicine study showed that ongoing exercise shrank sarcoma tumors in mice by approximately 50%. Based on the idea that regular exercise can reduce progression and rates in some cancers, researchers transplanted murine sarcoma cells into mice in 3 groups. These 3 groups were controls, mice exercising until tumor transplantation, and mice continuing exercise after transplantation. Researchers concluded that, although the mechanism was unknown, tumor size decreased significantly in mice continuing exercise after transplantation.