Postdiagnosis recreational physical activity and breast cancer prognosis: Global Cancer Update Programme (CUP Global) systematic literature review and meta‐analysis

Abstract

It is important to clarify the associations between modifiable lifestyle factors such as physical activity and breast cancer prognosis to enable the development of evidencebased survivorship recommendations. We performed a systematic review and metaanalyses to summarise the evidence on the relationship between postbreast cancer diagnosis physical activity and mortality, recurrence and second primary cancers. We searched PubMed and Embase through 31st October 2021 and included 20 observational studies and three follow-up observational analyses of patients enrolled in clinical trials. In linear dose-response meta-analysis of the observational studies, each 10-unit increase in metabolic equivalent of task (MET)-h/week higher recreational physical activity was associated with 15% and 14% lower risk of all-cause (95% confidence interval [CI]: 8%-22%, studies = 12, deaths = 3670) and breast cancer-specific mortality (95% CI: 4%-23%, studies = 11, deaths = 1632), respectively. Recreational physical activity was not associated with breast cancer recurrence (HR = 0.97, 95% CI: 0.91-1.05, studies = 6, deaths = 1705). Nonlinear dose-response meta-analyses indicated 48% lower all-cause and 38% lower breast cancer-specific mortality with increasing recreational physical activity up to 20 MET-h/week, but little further reduction in risk at higher levels. Predefined subgroup analyses across strata of body mass index, hormone receptors, adjustment for confounders, number of deaths, menopause and physical activity intensities were consistent in direction and magnitude to the main analyses. Considering the methodological limitations of the included studies, the independent Expert Panel concluded 'limited-suggestive' likelihood of causality for an association between recreational physical activity and lower risk of all-cause and breast cancer-specific mortality.

Postdiagnosis body fatness, recreational physical activity, dietary factors and breast cancer prognosis: Global Cancer Update Programme (CUP Global) summary of evidence grading

“…We included 20 longitudinal observational studies in the systematic review 11 . Most of these articles published data on recreational physical activity; thus, studies that evaluated total physical activity, nonrecreational physical activity, physical activity changes and sedentary behaviour were descriptively synthesised.…”

“…We included 20 longitudinal observational studies in the systematic review. 11 Most of these articles published data on recreational physical activity; thus, studies that evaluated total physical activity, nonrecreational physical activity, physical activity changes and sedentary behaviour were descriptively synthesised. There were also three exploratory RCTs from two publications that met our inclusion criteria, 25 , 26 and their results suggested a beneficial effect of physical activity interventions on outcomes after breast cancer, but these findings were limited by small numbers of events and wide CIs.…”

“…An independent Expert Panel graded the quality of the evidence. This article presents the summary of the evidence grading and more details on the rationale, methods and findings are provided in the accompanied systematic review articles 10‐12 …”

Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta‐analysis

“…We conducted updated systematic literature reviews and meta‐analyses to summarize the evidence published until and after 30 June 2012 of the previous report 5 and an independent Expert Panel evaluated the accumulated evidence. This paper presents the evidence on body fatness, weight change and breast cancer outcomes, whereas evidence on physical activity, diet and the overall summary is presented in the accompanied papers 15‐17 …”

Postdiagnosis dietary factors, supplement use and breast cancer prognosis: Global Cancer Update Programme (CUP Global) systematic literature review and meta‐analysis

“…This article presents the evidence on dietary factors and supplement use and breast cancer outcomes, whereas evidence on body fatness, physical activity, and the overall summary is presented in the accompanied papers. 13 , 14 , 15 …”