Oral Green Tea Extract and Milk Thistle Extract to Colorectal Cancer Patients Undergoing Resection

Overview

Colorectal cancer is the third most common form of cancer found in the United States. To date surgical resection provides the best chance for cure. Unfortunately, despite "curative" surgery, tumor recurrences develop in 30-40% of patients from either unforeseen residual metastases or from viable tumor cells shed into the circulation before or at the time of surgery. There is evidence from both humans and mice suggesting that tumor growth is stimulated after surgery for a period of time. This study calls for the administration of a green tea extract and a milk thistle extract, two orally ingested supplements, during the week immediately before and weeks after your surgery. It is not the current standard of care to give anti-cancer drugs during the perioperative period. The basic idea behind this study is that it should be beneficial to inhibit cancer growth in the days leading up to and following surgery. Why is this the case? It makes sense to limit or inhibit tumor growth before surgery with drugs provided it can be done safely and does not interfere with the surgery. It is also logical to give anti-cancer drugs after surgery because, unfortunately, about 35 percent of colorectal cancer patients, after resection, have hidden tumor cells that remain in the body. There is also strong human evidence that tumor growth is stimulated during the first month after tumor resection as a result of the surgical injuries and the healing process. Therefore, there is good reason to give anti-cancer drugs as soon as possible after surgery in order to offset some of surgery's negative effects. Although both supplements have been given safely to a wide variety of patients with a number of different medical problems, the two supplements together have never been given to cancer patients during the weeks just before and following surgery. The researchers hypothesize that the administration of these two supplements together will be safe in the period surrounding colorectal cancer surgery.

Green tea extract and Silibinin (from the milk thistle plant) have both been shown in experimental studies to have anti-cancer effects as well as limited toxicity. Epigallocatechin-3-gallate (EGCG) is the major active catechin in green tea; it has been shown to prevent and limit tumor growth in murine models1-3. Silymarin, which is extracted from the seeds of the milk thistle plant, is used clinically as a hepatoprotective agent in Europe4. Its major active component, Silibinin, is well-tolerated and largely free of adverse effects5-6. In recent studies, Silibinin has been shown to inhibit the growth of a number of cancers in mouse models, including lung7, bladder8, liver9, prostate10, and colon11-12. Silibinin and EGCG have similar anti-neoplastic mechanisms including: 1) cell cycle arrest via upregulation of P21 and P27 and downregulation of CDK, 2) induction of apoptosis via Caspase-3 activation and cleavage of poly (ADP-ribose) polymerase (PARP), and 3) suppression of angiogenesis and metastasis via inhibition of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP-9)