paywalled: Physical Activity, Biomarkers, and Disease Outcomes in Cancer Survivors: A Systematic Review

Physical Activity, Biomarkers, and Disease Outcomes in Cancer Survivors: A Systematic Review:

Background
Cancer survivors often seek information about how lifestyle factors, such as physical activity, may influence their prognosis. We systematically reviewed studies that examined relationships between physical activity and mortality (cancer-specific and all-cause) and/or cancer biomarkers.

Methods
We identified 45 articles published from January 1950 to August 2011 through MEDLINE database searches that were related to physical activity, cancer survival, and biomarkers potentially relevant to cancer survival. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement to guide this review. Study characteristics, mortality outcomes, and biomarker-relevant and subgroup results were abstracted for each article that met the inclusion criteria (ie, research articles that included participants with a cancer diagnosis, mortality outcomes, and an assessment of physical activity).

Results
There was consistent evidence from 27 observational studies that physical activity is associated with reduced all-cause, breast cancer–specific, and colon cancer–specific mortality. There is currently insufficient evidence regarding the association between physical activity and mortality for survivors of other cancers. Randomized controlled trials of exercise that included biomarker endpoints suggest that exercise may result in beneficial changes in the circulating level of insulin, insulin-related pathways, inflammation, and, possibly, immunity; however, the evidence is still preliminary.

Conclusions
Future research directions identified include the need for more observational studies on additional types of cancer with larger sample sizes; the need to examine whether the association between physical activity and mortality varies by tumor, clinical, or risk factor characteristics; and the need for research on the biological mechanisms involved in the association between physical activity and survival after a cancer diagnosis. Future randomized controlled trials of exercise with biomarker and cancer-specific disease endpoints, such as recurrence, new primary cancers, and cancer-specific mortality in cancer survivors, are warranted.

abstract: Priorities for cancer prevention: lifestyle choices versus unavoidable exposures

Priorities for cancer prevention: lifestyle choices versus unavoidable exposures:
Source: The Lancet Oncology

"Although cancer prevention in the USA and other developed countries focuses on disease attributable to lifestyle factors such as smoking, alcohol intake, sun exposure, and obesity, cancer caused by involuntary exposures is a concern. The term environmental is ambiguously used to distinguish between lifestyle and unavoidable exposures. The general community is said to be vulnerable to carcinogens encountered in pollution, contaminated food, and consumer products. In view of these concerns, assessments of the carcinogenicity of particular chemicals are of little assistance in prevention of cancer. Appraisal of cancer attributable to widespread and localised pollution, pesticides, endocrine disrupting chemicals, and consumer products yields diverse outcomes, from established causation to absence of harm. The precautionary principle is not a practicable approach for unknown carcinogenic risks. Procedures for individuals to reduce exposure to recognised or suspect carcinogens in consumer products are not effective measures for cancer prevention. Anxiety concerning insidious cancer causation could divert attention from proven means of cancer prevention."

Secrets To Longevity: It's Not All About Broccoli : NPR (genes vs lifestyle)

abstract: Feasibility of a lifestyle intervention for ovarian cancer patients receiving adjuvant chemotherapy

OBJECTIVES

This study aimed to assess the feasibility of a lifestyle intervention for promoting physical activity (PA) and diet quality during adjuvant chemotherapy for ovarian cancer.

METHODS:

Patients were enrolled post-operatively and received PA and nutrition counseling, at every chemotherapy visit for six cycles. Quality of life (QoL) was measured with the Functional Assessment of Cancer Therapy (FACT-G), PA with the Leisure Score Index (LSI), dietary intake with 3-day food records, and symptom severity/distress by the Memorial Symptom Assessment Scale (MSAS). Pedometer step count was collected during chemotherapy cycles.

RESULTS:

Recruitment was 73% with 27 patients enrolled. Mean [95% confidence interval] change in minutes of PA from cycle #3 to following cycle #6 was 61min [-3, 120] p=0.063, and from baseline to after cycle #6 was 73min [-10, 15]; p=0.082. Mean change in total fruit and vegetable consumption between baseline and during chemotherapy was 0.56 [-0.09, 0.64]; p=0.090. FACT-G increased from 75.4 at baseline to 77.6 during chemotherapy and 83.9 following chemotherapy (p=0.001 for change from baseline to post-chemotherapy).


Mean total MSAS ( Memorial Symptom Assessment Scale) score was 20.6 at baseline, 26.6 at cycle #3 and decreased to 17.0 following chemotherapy (p=0.01 comparison of cycle #3 and following chemotherapy). Increased moderate to strenuous PA was correlated with higher physical well-being during chemotherapy (r=0.48, p=0.037).

CONCLUSIONS:

Lifestyle counseling during adjuvant chemotherapy for ovarian cancer is feasible and may improve PA and diet quality. Randomized controlled trials examining the effects of lifestyle counseling on quality of life and treatment outcomes in ovarian cancer patients are warranted.

Weight, Physical Activity, Diet, and Prognosis in Breast and Gynecologic Cancers — JCO

Abstract

Diet, physical activity, and weight may affect prognosis among women who are diagnosed with breast or gynecologic cancer. Observational studies show associations between being overweight or obese and weight gain with several measures of reduced prognosis in women with breast cancer and some suggestion of poor prognosis in underweight women. Observational studies have shown an association between higher levels of physical activity and improved breast cancer–specific and all-cause mortality, although a dose-response relationship has not been established. One large randomized controlled trial reported increased disease-free survival after a mean of 5 years in patients with breast cancer randomly assigned to a low-fat diet versus control. However, another trial of similar size found no effect from a high vegetable/fruit, low-fat diet on breast cancer prognosis. The few reported studies suggest that obesity negatively affects endometrial cancer survival, while the limited data are mixed for associations of weight with ovarian cancer prognosis. Insufficient data exist for assessing associations of weight, physical activity, or diet with prognosis in other gynecologic cancers. Associations of particular micronutrient intake and alcohol use with prognosis are not defined for any of these cancers. The effects of dietary weight loss and increase in physical activity on survival or recurrence in breast and gynecologic cancers are not yet established, and randomized controlled trials are needed for definitive data.

Time Course of Risk Factors in Cancer Etiology and Progression — JCO

Blogger's Note: in the absence of the full paper, 'may' is not definitive

 Abstract

Patients with cancer increasingly ask what they can do to change their lifestyles and improve outcomes. Risk factors for onset of cancer may differ substantially from those that modify survival with implications for counseling. This review focuses on recent data derived from population-based studies of causes of cancer and of patients with cancer to contrast risk factors for etiology with those that impact survival. For different cancer sites, the level of information to inform the timing of lifestyle exposures and risk of disease onset or progression after diagnosis is often limited. For breast cancer, timing of some exposures, such as radiation, is particularly important. For other exposures, such as physical activity, higher levels may prevent onset and also improve survival. For colon cancer, study of precursor polyps has provided additional insight to timing. Extensive data indicate that physical activity reduces risk of colon cancer, and more limited data suggest that exposure after diagnosis improves survival. Dietary factors including folate and calcium may also reduce risk of onset. More limited data on prostate cancer point to obesity increasing risk of aggressive or advanced disease. Timing of change in lifestyle for change in risk of onset and for survival is important but understudied among patients with cancer. Counseling patients with cancer to increase physical activity and avoid weight gain may improve outcomes. Advice to family members on lifestyle may become increasingly important for breast and other cancers where family history is a strong risk factor.

Abstract: The role of body mass index, physical activity, and diet in colorectal cancer recurrence and survival: a review of the literature.

"In conclusion, only a paucity of data is available about the effect of dietary and other lifestyle factors on colorectal cancer recurrence and survival. Thus far, no clear conclusions can be drawn. Future studies are warranted, particularly on postdiagnosis BMI and diet."

Breast Cancer Genetic Risks Not Affected By Lifestyle Factors