Prospective cohort study of lifetime physical activity and breast cancer survival

Division of Population Health, Alberta Cancer Board, Calgary, AB, Canada.
International Journal of Cancer (Impact Factor: 5.01). 04/2009; 124(8):1954-62. DOI: 10.1002/ijc.24155
Source: PubMed

ABSTRACT Few studies have examined the association between physical activity and disease outcomes in breast cancer survivors. Here, we report the association between lifetime total physical activity performed prior to diagnosis and disease outcomes in a population-based sample of breast cancer survivors. A cohort of 1,231 women diagnosed with breast cancer between 1995 and 1997 was followed for a minimum of 8.3 years for any cancer progressions, recurrences and new primaries; and a minimum of 10.3 years for deaths. All treatment and follow-up care received was abstracted from medical records. Data on physical activity including type (occupational, household, recreational) and dose (frequency, intensity and duration) performed during the entire lifetime until diagnosis were examined in Cox proportional hazards models as well as with cumulative incidence curves. An average of 126 MET-hr/week were reported for total physical activity (of which 13.9, 46.9 and 65.3 MET-hr/week were, respectively, for recreational, occupational and household activity). A decreased risk of breast cancer death and all deaths was observed among women in the highest versus the lowest quartiles of recreational activity (MET-hr/week/year) (HR = 0.54, 95% CI = 0.36-0.79). Both moderate (0.56, 95% CI = 0.38-0.82) and vigorous intensity recreational activity (0.74, 95% CI = 0.56-0.98) decreased the risk of breast cancer death. Moderate intensity recreational activity decreased the risk of a recurrence, progression or new primary cancer (0.66, 95% CI = 0.48-0.91). No other association with breast cancer survival was observed for other types of physical activity. Prediagnosis recreational activity conferred a benefit for survival after breast cancer. Moderate intensity recreational activity was particularly protective.

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    ABSTRACT: We investigated the association of physical activity with survival for 601 Hispanic women and 682 non-Hispanic white women who participated in the population-based breast cancer case-control New Mexico Women's Health Study. We identified 240 deaths among cases diagnosed with a first primary invasive breast cancer between 1992 and 1994, and 88 deaths among controls. Follow-up extended through 2012 for cases and 2008 for controls. Multivariable hazard ratios (HRs) and 95 % confidence intervals (CIs) were estimated using Cox proportional hazards regression. Higher levels of total physical activity were inversely associated with all-cause mortality among Hispanic cases (Quartile (Q)4: HR = 0.55, 95 % CI 0.31-0.99). A non-significant trend was observed for recreational activity in Hispanic cases also (Q4: HR = 0.50, 95 % CI 0.23-1.09, p for trend = 0.08). No significant associations were noted for non-Hispanic white cases or for controls. The results suggest that increasing physical activity may be protective against mortality in Hispanic women with breast cancer, despite reporting lower levels of recreational activity than non-Hispanic white women or Hispanic controls. Public health programs in Hispanic communities should promote physical activity in women as a means of decreasing breast cancer risk and improving survival.
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    ABSTRACT: Background: Substantial observational evidence exists which supports a role for physical activity in improving breast cancer prognosis. Biological pathways linking physical activity to prognosis include alterations in obesity-related biomarkers involving chronic low-grade inflammation, adipokines, and markers of insulin resistance. Exercise interventions, with these biomarkers as end-points, may be beneficial for improving breast cancer outcomes. Objective: To conduct a systematic literature review, investigating the effect of exercise interventions on anthropometric variables and related biomarkers of cancer risk in breast cancer survivors. Methods: The preferred reporting for systematic review and meta-analysis (PRISMA) guidelines were followed. A comprehensive literatures search was conducted using the databases PubMed, Embase, SciVerse, the Cochrane Library, AMED, and PEDro, for articles published in English up to June 2012. Exercise interventions, both randomized and non-randomized, examining a range of biomarkers of cancer risk were included. Results: Thirteen articles, representing nine exercise interventions were included — seven randomized controlled trials (RCT) and two non-randomized trials. A number of trials reported improvements in anthropometrics (percentage body fat, body mass index, and waist / hip circumference). Three trials reported changes in insulin-like growth factor (IGF)-I and IGF-II, and insulin-like growth factor binding protein (IGFBP)-3. There were no reported changes in insulin, glucose, insulin resistance, adipokines or inflammatory markers. Conclusions: More robust RCTs are required to fully elucidate the effect of exercise training on biomarkers of breast cancer risk and determine the role of physical activity as an adjunct to breast cancer treatment as a means of reducing breast cancer recurrence and improving mortality.
    Physical Therapy Reviews 04/2013; 18(2):79-89. DOI:10.1179/1743288X12Y.0000000057
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    ABSTRACT: Strong evidence exists supporting the effect of lack of physical activity on the risk of developing breast cancer. However, studies examining the effects of physical activity on breast cancer outcomes, including survival and prognosis have been inconclusive. Therefore, the aim of the current study was to provide a systematic review and meta-analysis of studies investigating the association between physical activity and breast cancer recurrence and death. Methods. PubMed, EMBASE, and CENTRAL databases were searched up to 18 October 2014. Reference lists of retrieved articles and relevant previous reviews were also searched. Observational studies that reported risk estimates for all-cause and/or breast cancer-related death and/or breast cancer recurrences by levels of physical activity, were included in the review. Random effects models were used to calculate pooled hazard ratios (HR) and 95% confidence intervals (CI) and to incorporate variation between studies. The Newcastle-Ottawa scale was used to critically appraise the risk of bias across studies. Results. Twenty-two prospective cohort studies were eligible in this meta-analysis. During average follow-up periods ranging from 4.3 to 12.7 years there were 123 574 participants, 6898 all-cause deaths and 5462 breast cancer outcomes (i.e. breast cancer-related deaths or recurrences). The average Newcastle-Ottawa score was six stars (range 4–8). Compared to those who reported low/no lifetime recreational pre-diagnosis physical activity, participants who reported high lifetime recreational pre-diagnosis physical activity levels had a significantly lower risk of all-cause (HR = 0.82, 95% CI 0.70–0.96, p < 0.05) and breast cancer-related death (HR = 0.73, 95% CI 0.54–0.98, p < 0.05). Significant risk reductions for all-cause and breast cancer-related death was also demonstrated for more recent pre-diagnosis recreational physical activity (HR = 0.73, 95% CI 0.65–0.82, p < 0.001; and HR = 0.84, 95% CI 0.73–0.97, p < 0.05, respectively), post-diagnosis physical activity (HR = 0.52, 95% CI 0.43–0.64, p < 0.01; and HR = 0.59, 95% CI 0.45–0.78, p < 0.05, respectively) and meeting recommended physical activity guidelines (i.e. ≥ 8 MET-h/wk) post-diagnosis (HR = 0.54, 95% CI 0.38–0.76, p < 0.01; and HR = 0.67, 95% CI 0.50–0.90, p < 0.01, respectively). However, there was evidence of heterogeneity across lifetime recreational pre- and post-diagnosis physical activity analyses. Both pre-diagnosis (lifetime and more recent combined) and post-diagnosis physical activity were also associated with reduced risk of breast cancer events (breast cancer progression, new primaries and recurrence combined) (HR = 0.72 95% CI 0.56–0.91, p < 0.01; and HR = 0.79, 95% CI 0.63–0.98, p < 0.05, respectively). Conclusion. There is an inverse relationship between physical activity and all-cause, breast cancer-related death and breast cancer events. 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.
    Acta Oncologica 03/2015; DOI:10.3109/0284186X.2014.998275 · 3.71 Impact Factor

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