Oral contraceptives and epithelial ovarian - Cancer does dose matter?

OBJECTIVE: To determine the risk of ovarian cancel among women who use low- estrogen-dose oral contraceptives. STUDY DESIGN: The stimy used data on white women under 70 years of age who had been enrolled in a population-based case-control study conducted betwee n 1986 and 1988 in three western Washington counties. Women with ovarian ca ncer (n = 276) were ascertained through a population-based cancer registry, and controls (n = 391) were selected by random digit dialing. Unconditiona l logistic regression mns used to estimate the risk of ovarian cancer assoc iated with oral contraceptive use. RESULTS: After adjustment for age and parity, women who took oral contracep tives for at least three months were at decreased risk of ovarian cancer (o dds ratio [OR] 0.8, 95% confidence interval [CI] 0.5-1.1) relative to women who never used this form of contraception. The reduced risk of ovarian can cer was present among women whose only preparation contained a low (< 50 mu g ethinyl estradiol or <80 mu g mestranol) (OX 0.6, 95% CI 0.3-1.1) find h igh (OX 0.8, 95% CI 0.5-1.2) estrogen nose. CONCLUSION: While our results are limited in their statistical precision an d by the inability of many subjects to recall the brands of oral contracept ives that they took, they suggest that the neu)er, low-estrogen-nose oral c ontraceptives confer a benefit regarding ovarian cancer risk similar to tha t conferred by earlier, high-estrogen-dose formulations.