Breast cancer and depot-medroxyprogesterone acetate: a review

Synergistic tumor promoter effects of estrone and progesterone in methylnitrosourea-induced rat mammary cancer

Tumor promoter effects of steroid hormones were tested in ovariectomized rats treated with the tumor initiator, methylnitrosourea. Continuous treatment with low doses of estrone induced tumor in 55% of experimental animals while intact control animals had a 96-100% incidence. Although progesterone alone produced no tumors in ovariectomized, methylnitrosourea-treated animals, estrone and progesterone acted synergistically, inducing tumorigenesis in 88% of treated rats. These results point to an important interaction between estrogens and progestins in promoting mammary tumorigenesis.

Protective effect of depot-medroxyprogesterone acetate on surgically treated uterine leiomyomas: a multicentre case--control study

OBJECTIVE

To assess the protective effect of depot-medroxyprogesterone acetate (DMPA) on uterine leiomyomas. DMPA has been widely used in Thailand for many years; uterine leiomyomas is the most common female tumour.

DESIGN

A multicentre hospital-based case--control study.

SETTING

University and regional hospitals.

PATIENTS

Cases were all newly diagnosed patients with pathologically proven diagnosis of uterine leiomyomas, who were admitted to eight hospitals in three regions of Thailand from January 1991 to June 1993. Three controls matched with cases by sex, age within five years and date of admission within three months were recruited.

MAIN OUTCOME MEASURES

Information on socio-demographic factors, personal and family history, current disease, reproductive and contraceptive history was collected from cases and controls by interview.

RESULTS

There were 910 cases and 2709 controls. After univariate and unconditional multiple logistic regression analysis, risk factors associated positively with uterine leiomyomas are tubal ligation, family history of uterine leiomyomas, higher education, obesity and abortion. In contrast, DMPA, use of oral contraceptives, higher parity and smoking are associated with a lower relative risk suggesting that they have a protective effect against uterine leiomyomas. This causative relation is further strengthened by the strong duration-response relation between DMPA and uterine leiomyomas. This protection may persist for more than 10 years after the last dose.

CONCLUSION

We have demonstrated a strong, duration dependent protective effect of DMPA against uterine leiomyomas.

Pharmacokinetics of centchroman in healthy female subjects after oral administration

The pharmacokinetics of centchroman, a non-steroidal antifertility agent, were assessed in serum of eleven healthy female subjects after a single 30 mg oral dose. Maximum serum concentration (Cmax) of 55.53 (s.d., 15.45) microgram/L was attained at 5.18 (s.d., 1.78) h after oral administration. The concentration-time profile was best described by a two-compartment open model with bi-exponential disposition functions. The mean terminal elimination half-life (t1/2) was 165 (s.d., 49) h with a clearance of 6.17 (s.d., 1.67) L/h and volume of distribution of 1420 (s.d., 478) L. Comparison of the pharmacokinetic parameters of this study with those obtained after a single 60 mg oral dose did not show statistically significant differences in the rate of absorption, distribution and elimination. The Cmax and AUC0-infinity were dose-dependent. Thus, the absorption and disposition of centchroman are of first-order, reproducible and dose-dependent.