Modern society is a sedentary society. You don’t need me to tell you exercise is important. You already know that.
Research, both epidemiological and cohort studies, suggests that exercise can help reduce the risk of some breast cancers, particularly for pre-menopausal women. Exercise also helps reduce the risk of recurrence for menopausal women, with possibly a more positive effect for estrogen receptor positive breast cancer.
Physical activity is inversely associated with and sedentary behaviour is positively (and independently) associated with an increased risk of more than ten types of cancer, including colorectal cancer (and advanced adenomas), endometrial cancers, and breast cancer.
New findings demonstrate that engaging in even minimal amounts of exercise is protective against breast cancer. Further, numerous studies have identified the role of exercise in the treatment of breast cancer and improvement in treatment side effects, quality of life, and overall survival.
Researchers examined 6831 self-reported cancer cases and 1992 self-reported cancer-free controls from the Cancer Lifestyle and Evaluation of Risk Study. Breast cancer risk was lower for those with low and moderate levels of physical activity (PA). “These findings suggest that PA and obesity are independent cancer risk factors.”
Women who report adherence to international physical activity recommendations entail a significant decrease in risk for all pathologic breast cancer subtypes.
Strong epidemiologic evidence documents the protective effect of physical activity on breast cancer risk, recurrence, and mortality… our findings offer a mechanistic explanation for exercise-dependent suppression of breast cancer cell growth.
From 2016:
Across 26 studies of breast, colorectal, and prostate cancer patients, a 37% reduction was seen in risk of cancer-specific mortality, comparing the most versus the least active patients. Risks of recurrence or recurrence/cancer-specific death (combined outcome) were also reduced based on fewer studies.
Researchers performed a meta-analysis of 22 cohort studies with 123,574 participants. “There is an inverse relationship between physical activity and all-cause, breast cancer-related death and breast cancerevents. The current meta-analysis supports the notion that appropriate physical activity may be an important intervention for reducing death and breast cancer events among breast cancer survivors.”
In the prospective National Institutes of Health-AARP Diet and Health Study, researchers followed 293,511 men and women. Over a median 12.1 years, 15,001 died of cancer. The researchers focused on moderate to vigorous intensity leisure time physical activity (MVPA). Patients reporting >7 hr/week of MVPA had a lower risk of dying of cancer than patients reporting never/rare MVPA.
We analyzed data from 59,308 postmenopausal women (2,155 incident invasive breast cancers) followed between 1993 and 2005 (8.5 years postmenopause on average) through biennial questionnaires…Our results suggest a decrease in risk associated with recent recreational physical activity even of modest levels.
Researchers analyzed 31 studies with 63,786 cases. There was an inverse association between recreational, occupational and household activity and a breast cancer diagnosis. A stronger association was found for patients with a BMI <25 kg/m, premenopausal women, and those with estrogen and progesterone receptor-negative breast cancer (this is a minority group).
A meta-analyses of observational studies supports the concept that moderate recreational physical activity (about 3-4 h walking per week) may reduce breast cancer incidence and that women with early stage breast cancer who increased or maintain their physical activity may have lower recurrence risk as well.
Epidemiologic evidence supports an inverse association between physical activity and postmenopausal breast cancer… Among 73,615 postmenopausal women in the American Cancer Society Cancer Prevention Study II Nutrition Cohort, 4,760 women were diagnosed with breast cancer between 1992 and 2009… Forty-seven percent of women reported walking as their only recreational activity; among these women, a 14% lower risk was observed for ≥7 hours/week relative to ≤3 hours/week of walking… These results support an inverse association between physical activity and postmenopausal breast cancer that does not differ by ER status.
A comprehensive literature review identified six studies (12,108 patients with breast cancer) that focused on physical activity (PA) and breast cancer. Patients with estrogen receptor (ER)-positive tumors who engaged in physical activity post-diagnosis had a 34% reduction in breast cancer deaths.
Within the prospective Nurses’ Health Study, we assessed the associations of specific and total activity, queried every 2 to 4 years since 1986, with breast cancer risk… Activity was measured as hours of metabolic equivalent task values (MET-h)… Compared with less than 3 MET-h/wk (<1 h/wk walking), women engaged in higher amounts of recent total physical activity were at lower breast cancer risk … Compared with women who were least active at menopause and through follow-up… women who increased activity were at lower risk… Among specific activities modeled simultaneously, brisk walking was associated with lower risk.
We prospectively examined the relation between postdiagnosis recreational physical activity and risk of breast cancer death in women who had a previous invasive breast cancer diagnosed between 1988 and 2001 (at ages 20-79 years)… This study provides support for reduced overall mortality and mortality from breast cancer among women who engage in physical activity after breast cancer diagnosis.
Physical activity has been shown to decrease the incidence of breast cancer … Three MET-hours is equivalent to walking at average pace of 2 to 2.9 mph for 1 hour. The benefit of physical activity was particularly apparent among women with hormone-responsive tumors…. Physical activity after a breast cancer diagnosis may reduce the risk of death from this disease. The greatest benefit occurred in women who performed the equivalent of walking 3 to 5 hours per week at an average pace, with little evidence of a correlation between increased benefit and greater energy expenditure.
Great synopsis of the research on the benefits of exercise in warding off cancer, Kathy.
Thanks, Kevin.