Numerous lines of evidence point to the tumor promoting properties of prostaglandin (PG)E2. Preclinical studies have demonstrated the ability of both vitamin D (vitD) and celecoxib to downregulate the ecisanoid. We hypothesized that the two agents would work synergistically. The purpose of the study was to determine the dose dependent effects of vitD, with or without celecoxib. 24 women were prospectively enrolled and randomized in double blind fashion for one month (postmenopausal) or one menstrual cycle (premenopausal) to one of four daily treatment regimens: placebo, 400 IU vitD, 2000 IU vitD, or 2000 IU vitD + 400 mg celecoxib. Breast nipple aspirate fluid (NAF) and serum were collected. Both breast specific and systemic levels of PGE2 were measured. There was a significant dose dependent increase in 25(OH)D levels (p<.01). The post-treatment levels of NAF (but not serum) PGE2 were lower and the decrease greater in the 2000 IU vitD than in the other groups (p<.05) of normal risk women. A similar effect was not observed in women at increased breast cancer risk, nor in women receiving vitD + celecoxib. These findings suggest the potential of vitamin D, given in adequate dose, at lowering a key cancer promoting enzyme in women of normal breast cancer risk.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):B62.

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2011