Physical activity linked to reduced mortality in breast and colon cancer patients
Physical activity is associated with reduced breast and colon cancer mortality, but there is insufficient evidence on the association for other cancer types, according to a study published May 8 in the Journal of the National Cancer Institute.
Improvements in cancer treatment and screening have allowed cancer survivors to live longer and as a result, cancer survivors frequently look at information about how lifestyle factors like exercise can affect their prognosis. Multiple observational studies and randomized control trials (RCTs) have looked at the effects that physical activity can have on cancer survivors.
To examine the association between physical activity and cancer survival, Rachel Ballard-Barbash, M.D., of the Applied Research Program in the Division of Cancer Control and Population Sciences at the National Cancer Institute and colleagues reviewed 45 articles reporting both observational studies and randomized controlled trials (RCTs) that looked at the relationship between physical activity and mortality and/or cancer biomarkers among cancer survivors. The studies were published between January 1950 and August 2011. The researchers found that the RCTs with biomarker endpoints suggest that exercise may provide benefits to survivors’ insulin levels, reduce inflammation, and, possibly, improve immunity. The strongest evidence is for breast cancer survivors: most studies showed a statistically significant reduced risk of breast cancer and all-cause mortality associated with exercise. The next strongest evidence was for colorectal cancer survivors.
The authors point out that because of the diversity of the studies, it would be impossible to extrapolate specific recommendations on type and timing of physical activity. However, they can attest to the overall safety, physical and mental benefits of exercise for cancer survivors. They add that future RCTs should look at different types of exercise, as well as how obesity, weight loss, and cancer treatments may influence the effects of exercise on biomarkers. Also, how exercise may influence comorbidities in cancer survivors should be studied, they write.
Myth: Breast cancer is largely genetic.
Fact: Just 5 to 10% of cases are due to faulty breast cancer genes BRCA1 and BRCA2.
Even in women who have a family history, many cases are due not to specific gene mutations, according to the American Cancer Society, but, rather, to a combination of shared lifestyle factors and genetic susceptibilities. The truth is that scientists still have no idea what causes breast cancer - but new research is shedding light on what makes cancer return.
Myth: Breast cancer always appears as a lump.
Fact: Approximately 10% of those diagnosed with breast cancer have no lumps, pain, or other indications of a problem in their breasts.
And among lumps that are detected, 80 to 85% are benign. They’re often cysts or noncancerous tumors called fibroadenomas. That said, any lump or breast symptom (especially from the list below) that does not go away should be checked by a doctor.
- A change in how the breast or nipple feels or looks
- A lump or thickening in or near the breast or in the underarm area
- Breast pain or nipple tenderness
- A change in the size or shape of the breast
- A nipple or skin that turns inward into the breast
- Feeling warm to the touch
- Scaly, red, or swollen skin of the breast, areola, or nipple, perhaps with ridges or pitting that resembles an orange peel
- Nipple discharge
Myth: Mammograms prevent or reduce your risk.
Fact: Regular mammograms will not prevent or reduce your risk of breast cancer.
They just detect breast cancer that already exists - reducing deaths among breast cancer patients by about 16%. However, most breast cancers have been present for 6 to 8 years by the time they appear on mammograms, and screening misses up to 20% of all tumors. That’s why it’s important that all women have an annual breast exam performed by a health care provider and pay close attention to their own bodies to spot potential changes as early as possible. Getting a high-quality mammogram and having a clinical breast exam on a regular basis are the most effective ways to detect breast cancer in its earliest stages.
In an accompanying editorial, Edward L. Giovannucci, M.D., ScD, of the Department of Nutrition at the Harvard School of Public Health, writes that physical activity may extend the life-span of the cancer survivor, as well as their quality of life. “Even though direct effects of physical activity on cancer are not definitely proven, given that physical activity is generally safe, improves quality of life for cancer patients, and has numerous other health benefits, adequate physical activity should be a standard part of cancer care,” he writes.
Global breast cancer mortality statistics.
Breast cancer mortality is declining in the United States, as well as in certain other industrialized areas - such as Canada, Austria, Germany, and the United Kingdom - possibly due to increased utilization of mammographic screening, early detection of disease, and availability of improved therapies. At least some of the decline has been attributed, however, to the higher fertility rates of the cohort of women born between 1924 and 1938 who bore children during the post-World War II period. In contrast, certain European nations - Spain, Portugal, Greece, Hungary, Poland, and Italy - have not reported these favorable trends. The lowest breast cancer mortality rates are reported in Asian regions, leading researchers to speculate that dietary, cultural, and/or environmental factors might be implicated in the etiology of the disease.
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Mettlin C.
Roswell Park Cancer Institute, Buffalo, NY, USA.
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Contact Info:
Article: Rachel Ballard-Barbash, .(JavaScript must be enabled to view this email address)
Editorial: Edward L. Giovannucci, .(JavaScript must be enabled to view this email address)
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Zachary Rathner
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301-841-1286
Journal of the National Cancer Institute