THE POTENTIAL FOR OXYTOCIN (OT) TO PREVENT BREAST-CANCER - A HYPOTHESIS

This hypothesis proposes that carcinogens in the breast are generated by the action of superoxide free radicals released when acinal gland d istension, under the influence of unopposed prolactin, causes microves sel ischaemia. Inadequate nipple care in the at-risk years leads to du ctal obstruction preventing the elimination of carcinogens from the br east. The regular production of oxytocin (OT) from nipple stimulation would cause contraction of the myoepithelial cells, relieving acinal g land distension and aiding the active elimination of carcinogenic flui d from the breast. Mechanical breast pump stimulation causes an increa se in plasma OT levels in the luteal but not in the follicular phase o f the menstrual cycle. OT production upon nipple stimulation in the lu teal phase of premenopausal, non-lactating women may be protective aga inst the high rates of mitotic breast cell division noted at this time via the potential to block the effect of oestrogen. The epidemiology of breast cancer suggests that lengthy lactation time is beneficial. S exual activity in nulliparous women also protects and OT levels have b een shown to rise with orgasm in women and in men. OT systems in the b rain are intricately linked to oestrogen and progesterone levels, and it is possible that these hormones may modify the OT secretory respons e both centrally and through an effect on the sensitivity of the breas t. OT production with nipple care and in sex and lactation, and the re duction in cycling ovarian hormones that occurs with pregnancy, may al l be important preventative factors in the development of breast cance r both pre- and post-menopausally.