Breast cancer research and treatment
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Breast Cancer Res. Treat. · Oct 2010
Review Meta AnalysisAdult weight gain in relation to breast cancer risk by estrogen and progesterone receptor status: a meta-analysis.
Adult weight gain is positively associated with postmenopausal breast cancer and inversely associated with premenopausal breast cancer risk. To date, no meta-analysis has been conducted to assess this association by estrogen receptor (ER) and progesterone receptor (PR) status. We searched PubMed for relevant studies published through March 2010. ⋯ Risk for ER(-)PR(-) tumors among postmenopausal women was also slightly increased (7 studies; RE = 1.34; 95% CI 1.06, 1.63), but statistically significantly different from risk for ER(+)PR(+) tumors (p (heterogeneity) < 0.0001). No associations were observed for ER(+)PR(-) tumors whereas risk for ER(-)PR(+) tumors could not be assessed. In conclusion, the association between adult weight gain and postmenopausal breast cancer risk is heterogeneous according to ER/PR status and stronger for ER(+)PR(+) than for ER(-)PR(-) tumors.
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Breast Cancer Res. Treat. · Oct 2010
Review Meta AnalysisEffect of obesity on survival of women with breast cancer: systematic review and meta-analysis.
Obesity is a risk factor for the development of new cases of breast cancer and also affects survival in women who have already been diagnosed with breast cancer. Early studies of obesity and breast cancer survival have been summarised in two meta-analyses, but the latest of these only included studies that recruited women diagnosed as recently as 1991. The primary aim of this study was to conduct a meta-analysis that included the more recent studies. ⋯ However, no study has elucidated the causal mechanism and there is currently no evidence that weight loss after diagnosis improves survival. Consequently, there is currently no reason to place the additional burden of weight loss on women already burdened with a diagnosis of cancer. Further research should concentrate on assessing whether factors such as diabetes or type of chemotherapy modify the obesity effect and on understanding the causal mechanism, in particular the role of relative under-dosing.