We systematically reviewed and synthesized evidence on the impact of physical activity/exercise on cancer treatment efficacy. We included six preclinical and seven clinical studies. Exercise ...significantly enhanced the efficacy of chemotherapy and tamoxifen in seven of eight rodent models in either an additive, sensitizing, or synergistic manner. In clinical studies, preliminary evidence indicates that exercise during neoadjuvant, primary, and adjuvant treatment may enhance efficacy of cancer therapies; however, no clinical study was designed for this purpose. Here we discuss the biological mechanisms of exercise-associated enhancement of therapeutic efficacy and propose future research directions to definitively examine the effects of exercise on cancer treatment and patient outcomes.
Breast cancer chemotherapy may cause unfavorable changes in physical functioning, body composition, psychosocial functioning, and quality of life (QOL). We evaluated the relative merits of aerobic ...and resistance exercise in blunting these effects.
We conducted a multicenter randomized controlled trial in Canada between 2003 and 2005 that randomly assigned 242 breast cancer patients initiating adjuvant chemotherapy to usual care (n = 82), supervised resistance exercise (n = 82), or supervised aerobic exercise (n = 78) for the duration of their chemotherapy (median, 17 weeks; 95% CI, 9 to 24 weeks). Our primary end point was cancer-specific QOL assessed by the Functional Assessment of Cancer Therapy-Anemia scale. Secondary end points were fatigue, psychosocial functioning, physical fitness, body composition, chemotherapy completion rate, and lymphedema.
The follow-up assessment rate for our primary end point was 92.1%, and adherence to the supervised exercise was 70.2%. Unadjusted and adjusted mixed-model analyses indicated that aerobic exercise was superior to usual care for improving self-esteem (P = .015), aerobic fitness (P = .006), and percent body fat (adjusted P = .076). Resistance exercise was superior to usual care for improving self-esteem (P = .018), muscular strength (P < .001), lean body mass (P = .015), and chemotherapy completion rate (P = .033). Changes in cancer-specific QOL, fatigue, depression, and anxiety favored the exercise groups but did not reach statistical significance. Exercise did not cause lymphedema or adverse events.
Neither aerobic nor resistance exercise significantly improved cancer-specific QOL in breast cancer patients receiving chemotherapy, but they did improve self-esteem, physical fitness, body composition, and chemotherapy completion rate without causing lymphedema or significant adverse events.
Summary
Excess body fat is a major risk factor for endometrial cancer incidence, but its impact on recurrence and survival remains unclear. The aim of this systematic review and meta‐analysis was to ...assess the association between excess body fat with recurrence, cancer‐specific, and all‐cause mortality among endometrial cancer survivors. We searched MEDLINE and EMBASE databases up to July 2021. Risk of bias was assessed with the Ottawa Newcastle Scale. Random effects models estimated pooled hazard ratios for the main associations between body mass index (BMI) and survival outcomes and stratified by endometrial cancer type. Potential heterogeneity and publication bias were evaluated with sensitivity analyses, funnel plots, and Egger's test. Forty‐six studies were included, of which 45 estimated body fat with BMI and six used direct waist circumference measures or CT/MRI scans. Higher BMI (≥30 kg/m2) was associated with increased all‐cause mortality (HR = 1.34, 95%CI = 1.12–1.59) and recurrence (HR = 1.28, 95%CI = 1.06–1.56). In sub‐group analysis, associations between higher BMI and all‐cause mortality were observed for both Types I and II survivors, while recurrence associations were only significant among Type I cases. Obesity at endometrial cancer diagnosis was associated with increased cancer recurrence and all‐cause mortality among endometrial cancer survivors but not endometrial cancer‐specific mortality.
Convincing evidence now supports a probable preventive role for physical activity in postmenopausal breast cancer. The mechanisms by which long-term physical activity affect risk, however, remain ...unclear. The aims of this review were to propose a biological model whereby long-term physical activity lowers postmenopausal breast cancer risk and to highlight gaps in the epidemiologic literature. To address the second aim, we summarized epidemiologic literature on 10 proposed biomarkers, namely, body mass index (BMI), estrogens, androgens, sex hormone binding globulin, leptin, adiponectin, markers of insulin resistance, tumor necrosis factor-alpha, interleukin-6, and C-reactive protein, in relation to postmenopausal breast cancer risk and physical activity, respectively. Associations were deemed "convincing," "probable," "possible," or "hypothesized" using set criteria. Our proposed biological model illustrated the co-occurrence of overweight/obesity, insulin resistance, and chronic inflammation influencing cancer risk through interrelated mechanisms. The most convincing epidemiologic evidence supported associations between postmenopausal breast cancer risk and BMI, estrogens, and androgens, respectively. In relation to physical activity, associations were most convincing for BMI, estrone, insulin resistance, and C-reactive protein. Only BMI and estrone were convincingly (or probably) associated with both postmenopausal breast cancer risk and physical activity. There is a need for prospective cohort studies relating the proposed biomarkers to cancer risk and for long-term exercise randomized controlled trials comparing biomarker changes over time, specifically in postmenopausal women. Future etiologic studies should consider interactions among biomarkers, whereas exercise trials should explore exercise effects independently of weight loss, different exercise prescriptions, and effects on central adiposity.
Abstract
Background
Although socioeconomic status (SES) has been shown to modify associations between the neighborhood built environment and physical activity, contradictory results exist. Objectives ...of this cross-sectional and longitudinal analysis were to: 1) examine whether overall neighborhood walkability and specific built characteristics were associated with walking among adults at a single point in time and after they relocate neighborhoods, and 2) test for effect modification of these associations by SES.
Methods
We linked longitudinal data from 703 adults who relocated urban neighborhoods between two waves of Alberta’s Tomorrow Project (2008–2015) to neighborhood built environment data. We created a walkability index from measures of population counts, street connectivity, and destination diversity within 400 m of participants’ homes. In cross-sectional analyses, we used generalized linear models to estimate associations between built characteristics and minutes walked per week at baseline. For the longitudinal analyses, we used fixed-effects linear regression models to estimate associations between changes in built characteristics and minutes walked per week. We also assessed if indicators of SES (individual education or household income) modified both sets of associations.
Results
Most cross-sectional and longitudinal associations were small and statistically non-significant. Neighborhood population count (
b
= 0.03, 95% CI: 0.01, 0.07) and street connectivity (
b
= − 1.75, 95% CI: − 3.26, − 0.24) were cross-sectionally associated with walking duration among the overall sample. None of the longitudinal associations were statistically significant among the overall sample. There was limited evidence of effect modification by SES, however, we found negative cross-sectional associations between street connectivity and walking among adults with lower education and income, and a positive association between percent change in walkability and change in walking among lower educated adults.
Conclusions
Despite population count and street connectivity being associated with walking at baseline, changes in these built environment variables were not associated with changes in walking following residential relocation. Our findings also provide evidence, albeit weak, that changes in neighborhood walkability, resulting from residential relocation, might more strongly affect walking among low SES adults. Further longitudinal research is needed to examine built environment characteristics with walking for different purposes and to test for inequitable socioeconomic impacts.
Physical activity, sufficient sleep, and limiting sedentary time may improve cancer survivorship.
Utilizing US nationally representative samples from the National Health Interview Survey 1997-2018 ...and the National Health and Nutrition Examination Survey 2007-2018, this study investigated the trends of meeting physical activity guidelines, insufficient sleep duration, and sitting time in US cancer survivors (n = 58 527) and noncancer adults (n = 640 109).
From 1997 to 2018, the prevalence of meeting physical activity guidelines was consistently lower in cancer survivors than in noncancer adults. Among cancer survivors, the prevalence of meeting physical activity guidelines increased from 34.9% (95% confidence interval CI = 33.1% to 36.8%) to 46.5% (95% CI = 45.0% to 48.1%) for aerobic (≥150 minutes per week at moderate intensity or 75 minutes per week at vigorous intensity), from 13.9% (95% CI = 12.8% to 15.1%) to 23.1% (95% CI = 21.8% to 24.4%) for muscle strengthening (≥2 days per week) activities, and from 9.5% (95% CI = 8.4% to 10.7%) to 17.9% (95% CI = 16.7% to 19.1%) for both combined (all Ptrend < .001). From 2004 to 2018, the prevalence of insufficient sleep duration (<7 hours per day) increased from 28.4% (95% CI = 26.3% to 30.5%) to 30.8% (95% CI = 29.3% to 32.2%) (Ptrend = .004). Daily sitting time increased from 6.09 hours per day (95% CI = 5.71 to 6.46 hours per day) in 2007-2008 to 7.36 hours per day (95% CI = 7.05 to 7.68 hours per day) in 2013-2014 and attenuated to 6.20 hours per day (95% CI = 5.74 to 6.65 hours per day) in 2017-2018. The pattern of physical activity, sleep, and sitting time varied by sex, race and ethnicity, body mass index, cancer type, and time since cancer diagnosis.
More than half of US cancer survivors did not meet physical activity guidelines, and a large proportion had insufficient sleep duration and prolonged sitting time.
In 2018, the World Health Organisation (WHO) commenced a program of work to update the 2010 Global Recommendations on Physical Activity for Health, for the first-time providing population-based ...guidelines on sedentary behaviour. This paper briefly summarizes and highlights the scientific evidence behind the new sedentary behaviour guidelines for all adults and discusses its strengths and limitations, including evidence gaps/research needs and potential implications for public health practice.
An overview of the scope and methods used to update the evidence is provided, along with quality assessment and grading methods for the eligible new systematic reviews. The literature search update was conducted for WHO by an external team and reviewers used the AMSTAR 2 (Assessment of Multiple Systematic Reviews) tool for critical appraisal of the systematic reviews under consideration for inclusion. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) method was used to rate the certainty (i.e. very low to high) of the evidence.
The updated systematic review identified 22 new reviews published from 2017 up to August 2019, 14 of which were incorporated into the final evidence profiles. Overall, there was moderate certainty evidence that higher amounts of sedentary behaviour increase the risk for all-cause, cardiovascular disease (CVD) and cancer mortality, as well as incidence of CVD, cancer, and type 2 diabetes. However, evidence was deemed insufficient at present to set quantified (time-based) recommendations for sedentary time. Moderate certainty evidence also showed that associations between sedentary behaviour and all-cause, CVD and cancer mortality vary by level of moderate-to-vigorous physical activity (MVPA), which underpinned additional guidance around MVPA in the context of high sedentary time. Finally, there was insufficient or low-certainty systematic review evidence on the type or domain of sedentary behaviour, or the frequency and/or duration of bouts or breaks in sedentary behaviour, to make specific recommendations for the health outcomes examined.
The WHO 2020 guidelines are based on the latest evidence on sedentary behaviour and health, along with interactions between sedentary behaviour and MVPA, and support implementing public health programmes and policies aimed at increasing MVPA and limiting sedentary behaviour. Important evidence gaps and research opportunities are identified.
Physical inactivity and being overweight are modifiable lifestyle risk factors that consistently have been associated with a higher risk of postmenopausal breast cancer in observational studies. One ...biologic hypothesis underlying this relationship may be via endogenous sex hormone levels. It is unclear if changes in dietary intake, physical activity, or both, are most effective in changing these hormone levels.
This systematic review and meta-analysis examines the effect of reduced caloric dietary intake and/or increased exercise levels on breast cancer-related endogenous sex hormones.
We conducted a systematic literature search in MEDLINE, Embase, and Cochrane's Central Register of Controlled Trials (CENTRAL) up to March 2017. Main outcome measures were breast cancer-related endogenous sex hormones. Randomized controlled trials (RCTs) reporting effects of reduced caloric intake and/or exercise interventions on endogenous sex hormones in healthy, physically inactive postmenopausal women were included. Studies including women using hormone therapy were excluded. The methodological quality of each study was assessed by the Cochrane's risk of bias tool.
From the 2599 articles retrieved, seven articles from six RCTs were included in this meta-analysis. These trials investigated 1588 healthy postmenopausal women with a mean age ranging from 58 to 61 years. A combined intervention of reduced caloric intake and exercise, with durations ranging from 16 to 52 weeks, compared with a control group (without an intervention to achieve weight loss) resulted in the largest beneficial effects on estrone treatment effect ratio (TER) = 0.90 (95% confidence interval (CI) = 0.83-0.97), total estradiol TER = 0.82 (0.75-0.90), free estradiol TER = 0.73 (0.66-0.81), free testosterone TER = 0.86 (0.79-0.93), and sex hormone biding globulin (SHBG) TER = 1.23 (1.15-1.31). A reduced caloric intake without an exercise intervention resulted in significant effects compared with control on total estradiol TER = 0.86 (0.77-0.95), free estradiol TER = 0.77 (0.69-0.84), free testosterone TER = 0.91 (0.84-0.98), and SHBG TER = 1.20 (1.06-1.36). Exercise without dietary change, versus control, resulted in borderline significant effects on androstenedione TER = 0.97 (0.94-1.00), total estradiol TER = 0. 97 (0.94-1.00), and free testosterone TER = 0. 0.97 (0.95-1.00).
This meta-analysis of six RCTs demonstrated that there are beneficial effects of exercise, reduced caloric dietary intake or, preferably, a combination of exercise and diet on breast cancer-related endogenous sex hormones in physically inactive postmenopausal women.
Abstract The mechanisms by which aerobic fitness confers beneficial effects on cognition with aging are unclear but may involve cerebrovascular adaptations. In a cross-sectional study of women from ...the community ( n = 42; age range = 50–90 years), we sought to determine whether physical fitness is associated with higher cerebrovascular function, and its relationship to cognition. Main outcome measures included resting cerebral blood flow, cerebrovascular reserve, physical fitness (i.e., V ˙ O 2 max ) and cognition. Physically fit women had lower resting mean arterial pressure (MAP) and higher cerebrovascular conductance (CVC) than sedentary women. Overall cognition was negatively correlated with age and positively correlated with V ˙ O 2 max. V ˙ O 2 max was a predictor of resting CVC and MAP, and CVC and MAP when end-tidal gases were held constant at near-resting values. MAP and CVC were predictors of cognition. This study identified strong associations between physical fitness, vascular function and cognition, and provides new understanding regarding the mechanisms by which fitness positively impacts cognition with aging. The implications of this research are considerable and warrant future investigation.
Physical activity is consistently associated with a reduced risk of colorectal cancer in epidemiologic studies. This association among higher risk subgroups, such as those with a first-degree family ...history of colorectal cancer or high body mass index remains unclear.
We searched MEDLINE for studies examining physical activity and colorectal cancer risk among higher risk subgroups through July 11, 2017. Fifteen and three studies were eligible for inclusion for body mass index and first-degree family history of colorectal cancer subgroups, respectively. Estimates of the highest to lowest comparison of physical activity for each subgroup of risk were pooled using random-effects models.
The pooled associations of physical activity and colorectal cancer risk for those without and with a first-degree family history of colorectal cancer were 0.56 (95% confidence interval (CI) = 0.39-0.80) and 0.72 (95% CI = 0.39-1.32), respectively (p
= 0.586). The pooled associations of physical activity and colorectal cancer risk for the low and high body mass index groups were 0.74 (95% CI = 0.66-0.83) and 0.65 (95% CI = 0.53-0.79), respectively (p
= 0.389).
Overall, a stronger relative risk of physical activity on colorectal cancer risk was observed in the higher body mass index group, although the difference was not statistically significant, suggesting an added benefit of physical activity as a cancer prevention strategy in population groups with strong risk factors for colorectal cancer. Additional research among these subgroups is warranted.
PDF
