title: 4-Hydroxyandrostenedione in the prophylaxis of N-methyl-N-nitrosourea induced mammary tumourigenesis.
abstract: We have examined the role of the aromatase inhibitor 4-hydroxyandrostenedione (4-OHA) in the prevention of mammary tumourigenesis in experiments involving 170 rats. We first demonstrated a prophylactic effect of 4-OHA (50 mg/week) in reducing tumour incidence over a 30 week period compared to controls (P = 0.04). We repeated the experiment to determine optimum dose and duration of therapy. Although 4-OHA again prevented tumour development (P less than 0.0005), there was no difference between the standard (50 mg/week) dose and the higher dose (100 mg/week). Rats were randomised at 30 weeks to either stop or to continue prophylactic therapy; marginal benefit in tumour free survival in continuing therapy was observed (P = 0.03). We conclude that 4-OHA is an effective agent in preventing carcinogen-induced mammary tumours in rats and further studies of the role of oestrogen synthesis inhibitors in the prevention of human mammary tumours may be indicated.
authors.affiliation: Medical Oncology Unit, St George's Hospital Medical School, London, UK.
authors.forename: R C
authors.initials: RC
authors.lastname: Coombes
authors.forename: J R
authors.initials: JR
authors.lastname: Wilkinson
authors.forename: J M
authors.initials: JM
authors.lastname: Bliss
authors.forename: P
authors.initials: P
authors.lastname: Shah
authors.forename: D F
authors.initials: DF
authors.lastname: Easton
authors.forename: M
authors.initials: M
authors.lastname: Dowsett
mesh_terms: D000735:Androstenedione / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D047072:Aromatase Inhibitors; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000517:prevention & control*; D008770:Methylnitrosourea; D011897:Random Allocation; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D047072:Aromatase Inhibitors; D000735:Androstenedione; D008770:Methylnitrosourea; C014594:formestane