Portal de Periódicos da CAPES

Current Status of Sentinel Lymph Node Surgery for Breast Cancer

1999; Oxford University Press; Volume: 91; Issue: 4 Linguagem: Inglês

10.1093/jnci/91.4.302

1460-2105

David N. Krag,

Breast Implant and Reconstruction

The purpose of this review is to critically evaluate the collective epidemiologic evidence that a history of breastfeeding may decrease the risk of breast cancer.Original data for inclusion were identified through a MEDLINE® search of the English language literature from 1966 through 1998.To date, virtually all epidemiologic data regarding breastfeeding and breast cancer risk are derived from case-control studies, which vary according to classification of breastfeeding history.Overall, the evidence with respect to "ever" breast-feeding remains inconclusive, with results indicating either no association or a rather weak protective effect against breast cancer.An inverse association between increasing cumulative duration of breast-feeding and breast cancer risk among parous women has been reported in some, but not all, studies; the failure to detect an association in some Western populations may be due to the low prevalence of prolonged breast-feeding.It appears that the protective effect, if any, of long-term breast-feeding is stronger among, or confined to, premenopausal women.It has been hypothesized that an apparently protective effect of breast-feeding may be due to elevated breast cancer risk among women who discontinue breast-feeding or who take medication to suppress lactation; however, the evidence is limited and should be interpreted with caution.The biology underlying a protective effect of breast-feeding and why this should be restricted to premenopausal women remain unknown, although several mechanisms have been postulated (hormonal changes, such as reduced estrogen; removal of estrogens through breast fluid; excretion of carcinogens from breast tissue through breast-feeding; physical changes in the mammary epithelial cells, reflecting maximal differentiation; and delay of the re-establishment of ovulation).While breastfeeding is a potentially modifiable behavior, the practical implication of reduced breast cancer risk among premenopausal women with prolonged durations of breast-feeding may be of marginal importance, particularly in Western societies.[