The importance of new effective agents for breast cancer chemoprevention is highlighted by the fact that to date tamoxifen and raloxifene administration has not been completely accepted to reduce breast cancer risk, mostly because they are both associated with rare but serious toxic effects. Moreover, while SERMs and aromatase inhibitors do prevent the development of many ER-positive breast cancers, these drugs do not reduce the risk of ER-negative breast cancer. These results show that new approaches are needed also for the prevention of the latter.

Phytochemicals present in fruits, vegetables, wine, and some medical herbs, especially botanical polyphenolic antioxidants, have received increasing attention in the last decade as potential chemopreventive agents for different human cancers. However, so far there is a limited knowledge of the processes regulating the absorption of phytochemicals (and/or their metabolites) into the body, and how they reach their biological target. In spite of epidemiological studies and scientific evidences supporting the beneficial role of phytochemicals in blocking cancer initiation and progression, the trials have though failed to yield predicted results in randomized intervention studies.

Treatment in a window of opportunity (WOP) before surgery may improve clinical benefits and represents a very useful tool in selecting new chemopreventive agents against breast cancer. With this approach we will be able to study the kinetics of phytochemicals on the target organ as well as the effect on cell proliferation and other biomarkers by comparing the difference between pre- and post-treatment specimens.

In the present pilot pre-surgical trial, we will study the bioavailability of two natural products formulated in a phosphatydilcholine complex, Greenselect® Phytosome® (a standardized caffeine-free green tea extract) and Siliphos® (the polyphenolic flavonoid silybin isolated from milk thistle) in breast cancer tissue. Ten histologically confirmed primary breast cancer patients will receive Greenselect® Phytosome® 300 mg / day and ten patients will receive Siliphos® 2.8 g / day for four weeks before surgery. The primary endpoint is to assess the concentration of the active ingredients and their metabolites by high performance liquid chromatography (HPLC) in plasma, tumor and surrounding non-neoplastic tissues.

The study may provide important information for the development of future phase II clinical trials, specifically designed to explore the possible role of these two natural products in breast carcinogenesis. Moreover, the study will help to understand the biology and mechanisms of action of these potential chemopreventive agents.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):A58.