Ovarian function suppression with a GnRH analogue: D-ser(But[t])[6]-Arzgly[10]-LHRH (Goserelin) in hormone dependent canine mammary cancer

Hormones and hormone level modifying substances have long been used to trea t hormone-dependent tumours in humans. Recently, attempts have been made to use hormone manipulation regimens for the treatment of these tumours in ve terinary medicine. The aim of the present study was to evaluate the activit y of the luteinizing hormone-releasing hormone (LHRH)-agonist, D-ser(But[t] )[6]-Azgly[10]-LHRH (Goserelin) in hormone-dependent mammary cancer in dogs . Eighteen female dogs with hormone-dependent mammary cancer (T-2-T-4, N-0, M-0 according to TNM clinical staging classification) were selected and al located into two groups: nine dogs not treated with Goserelin (Group 1) ref erred to as control; and nine dogs treated with 60 mu g/kg depot Goserelin every 21 days for 12 months (Group 2), Goserelin treatment decreased circul ating levels of oestradiol and progesterone and reduced the size of mammary tumours; all the animals showed objective response (OR) to treatment after 3 months, and the relapse-free survival after 2 years was 88%. Haematology and blood chemistry parameters, measured every month from the beginning of treatment, as well as physical examination, showed that the drug was witho ut toxic effects. This suggests that, at the dose administered, Goserelin b locks the hypothalamus-pituitary-ovary axis, and consequently can be useful to treat hormone-dependent mammary tumours in female dogs.