Vaginal cytology as an aid to hormone therapy in postmenopausal cancer of the breast

Cytohormonal study of the vaginal smear is a simple and inexpensive method of selecting patients with mammary cancer who might benefit from castration in the years immediately following the menopause. It selects the patients in this age group for whom estrogen therapy is advised and also the patients in an older age group for whom hormone therapy other than estrogens is advised. It has a predictive function in selecting postmenopausal patients with mammary cancer for progestin therapy. Those patients whose pretreatment smear shows estatrophy (intermediate cell predominance) have a significantly higher tumor regression rate than those with teleatrophy (parabasal cell predominance). The pretreatment smear does not appear to have a similar predictive function with regard to androgen or estrogen therapy. On the other hand, a marked and persistent change in serial smear patterns during estrogen therapy is associated with a significantly higher rate of tumor regression than is a slight or transitory change. A successful attempt at increasing the estrogen effect upon the vaginal smear by concomitant administration of Methimazole was not associated with an increased incidence of tumor regression.