title: Predictive value of serum medroxyprogesterone acetate concentration for response in advanced or recurrent breast cancer.
abstract: Medroxyprogesterone acetate (MPA) is one of the most commonly prescribed drugs for endocrine therapy of metastatic breast cancer. In this study, the serum MPA concentration was measured by high-performance liquid chromatography (HPLC) and evaluated for its usefulness in predicting the response in 79 cases of advanced or recurrent breast cancers. Overall, 29 patients (37%) achieved an objective response. The response rate correlated significantly with the oestrogen receptor (ER) status (P = 0.03), proliferative activity determined by DNA polymerase alpha (P = 0.04), the disease-free interval (DFI) (P = 0.05) and the serum MPA concentration (P < 0.001). Patients with ER-positive tumours, lower proliferative activity, a longer (DFI) or a higher serum MPA concentration responded more frequently. The mean serum MPA concentration in the responders with ER-positive tumours (P = 0.01) or tumours with a lower proliferative activity (P = 0.008) were significantly lower than in cases with ER-negative tumours or tumours with a higher proliferative activity, respectively. Cases with soft tissue metastases showed responses at significantly lower MPA concentrations (P = 0.003) than those with bone or visceral metastases. Furthermore, there was a dramatic decrease in the MPA concentration when a responder with a high concentration became unresponsive to the therapy. Thus, the serum MPA concentration is a determining factor for the response to treatment.
authors.affiliation: Department of Surgery, Kumamoto City Hospital, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Nishimura
authors.forename: K
authors.initials: K
authors.lastname: Nagao
authors.forename: M
authors.initials: M
authors.lastname: Matsuda
authors.forename: K
authors.initials: K
authors.lastname: Baba
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: H
authors.initials: H
authors.lastname: Yamashita
authors.forename: M
authors.initials: M
authors.lastname: Fukuda
authors.forename: A
authors.initials: A
authors.lastname: Higuchi
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000097:blood* / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000556:secondary; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005544:Forecasting; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000097:blood* / Q000627:therapeutic use; D008593:Menopause / Q000097:blood; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011379:Prognosis; D011960:Receptors, Estrogen / Q000032:analysis; D012983:Soft Tissue Neoplasms / Q000556:secondary; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D017258:Medroxyprogesterone Acetate