Hormones and neoplasia.

A phenomenon, the explanation of which still eludes us, is the regression of human breast cancer which may follow alterations in the hormonal environment. It was first observed in 1895 when recurrent cancer of the breast in a 33-year-old Glasgow woman remitted following removal of the ovaries (Beatson, 1896). The therapeutic advances which followed this observation are well known and include the administration of androgens and oestrogens and removal of the adrenals and the pituitary (Loeser, 1938; Ulrich, 1939; Haddow, Watkinson, and Paterson, 1944; Huggins and Bergenstal, 1952; Luft, Olivecrona, and Sjogren, 1W). The remission rates achieved by these various mnehods of treatment are remarkably similar; appronimately one third of tumours have a beneficial Vponse. Although in most patients the effects ar*short lived, in some they are prolonged and well nigh dtamatic. considered to be oestrogen, adrenocortical steroids, and growth hormone. For full lobulo-alveolar development, equivalent to that at the termination of pregnancy, oestrogen, progesterone, prolactin, and growth hormone; and for the initiation of lactation, prolactin, growth hormone, and cortisol. In effect all the hormones shown in fig I have a part to play in normal growth of the breast. Although species differences almost certainly occur it is reasonable to assume that the mechanism of growth control of the human female breast is similar. Small wonder the difficulty in defining the role of hormones on breast neoplasia, particularly as hormones are only one of several factors involved in the initiation and promotion of a tumour.