Dr. Pike’s research interests are in the etiology and chemoprevention of breast, endometrial and ovarian cancer. A woman’s risks of endometrial and ovarian cancers are significantly reduced by use of combined estrogen-progestin oral contraceptives (COCs). The protection increases with duration of COC use and lasts for more than 30 years after the last use of a COC. Why COC use protects against endometrial cancer is well-understood, but why COC use protects against ovarian cancer is not. ‘Traditionally’ almost all COC packs have contained 21 active and 7 placebo pills, but recently the ratio of active to placebo pills has been changed to 24:4 and 84:7. These 24:4 and 84:7 COCs are predicted to add significantly to the protection of COCs against endometrial cancer. The effect of these COCs on ovarian cancer risk is unclear. If ovarian cancer risk reduction is determined through ovulation inhibition these changes will have little or no effect on the extent of risk reduction. If, however, the protection is through increased exposure to the progestin component of the COC then these changes could make the protection much greater. Dr. Pike is working with gynecologic faculty at MSK on understanding the mechanism of protection against ovarian cancer from COCs by studying the biology of the fallopian tube and cortical inclusion cysts within the ovary, the two sites where current evidence suggests most of the most common ovarian cancers arise. He is also working with gynecologic oncology faculty and pathology faculty at MSK and the University of Michigan to directly study the effect of contraceptives on the fallopian tube. He is continuing his epidemiological work on ovarian cancer with particular emphasis on the effects of breastfeeding, incomplete pregnancies, and ages at births and use of COCs. Dr. Pike is working with Dr. Jonine Bernstein and radiology faculty at MSK to evaluate whether breast magnetic resonance imaging can be used in a novel way through evaluation of ‘background parenchymal enhancement’ to identify women at greatly increased risk of breast cancer and to study the ‘activity’ of the breast as an aid to various studies of possible approaches to prevention of breast cancer, including changes in hormonal contraceptive formulations. He is working with gynecology and radiology faculty at Columbia University Medical Center on a new hormonal contraceptive approach using an anti-progestin for the prevention of breast cancer.