top of page
Key Findings

Completed Studies


The goal of this study was to find out if anti-estrogen compounds extracted from soy beans could have a cancer prevention effect in healthy women at high risk for breast cancer.  The study found that in postmenopausal women, no significant good or bad effects were seen on the breast. But in pre-menopausal women, there was a possibility that these soy compounds could increase the growth rate of breast cells, which is undesirable.  The outcome of the study was therefore to caution women - particularly younger women - against the use of soy extracts, although the consumption of whole soy foods (like edemame or tofu) has no known harmful effects.


Aspirin and Cancer Prevention

Aspirin use has been shown in many studies to have protective effects against colon cancer.  In this study, we tested a new way of looking at colon cells, to see if the beneficial effects of aspirin could be assessed after a short time of aspirin use,  by shining a light on the colon cells.  The study was successful in this regard; after three months of treatment, participants in the aspirin group showed normalization of these markers, but participants who received placebo did not.  Therefore, this new and accurate way of evaluating colon cells is being tested further in our ongoing studies and will be an important aid to studies of colon cancer prevention.



Selenium is a food component that has shown promise for cancer prevention, but clinical trials have shown mixed results.  In this study, we looked at a particular form of selenium given to healthy men, in three doses, to better understand the absorption of this compound when given by mouth, and the effects of different doses.


In a second selenium study, we conducted additional investigations to see what is the best form of selenium to use in cancer prevention studies. Healthy male volunteers took two different forms of selenium, to study relative absorption and excretion.  These two studies will guide the design of future prevention trials using selenium in people who are selenium-deficient.

Photo Therapy

Photodynamic Therapy for Prevention of Mouth Cancer

Over the past three decades, photodynamic therapy (PDT) has developed as a light-based tool which aids in the destruction of abnormalities that occur on the surface of organs, such as the skin, the lining of the mouth, the lung, and the gut. It involves the use of a drug that makes cancer and pre-cancer cells sensitive to laser light; when laser light is then applied to the abnormal areas, these are destroyed. In the mouth, people at risk for cancer may develop whitish patches called leukoplakia which can then progress to cancer.  This trial tested the safety and effectiveness of a newer form of PDT, and found that this was safe and had some effectiveness.  These findings help to form the basis for additional, larger trials in the future.

Colon Cancer Prevention with a Colon-Cleansing Laxative

Polyethylene glycol (PEG) is a laxative that is used to cleanse the colon in preparation for colonoscopy.  Findings from the laboratories at Northwestern and other universities suggested that PEG may also prevent colon cancer. We conducted the first human trial to evaluate early signals of colon protection, using two different doses of PEG versus a placebo.  We found that the use of PEG in this setting is safe, and changes suggestive of colonic protection were seen.  Larger trials are now needed to establish PEG as a strategy for colon cancer prevention.

CCP laxative

Tamoxifen as a Pill vs. a Gel for Safer Breast Cancer Prevention

Tamoxifen is a well proven medication for breast cancer prevention and the treatment of duct carcinoma in situ (DCIS, or Stage zero ductal cancer). However, many women decline tamoxifen pills for fear of side effects. In this study we tested a new way of delivering an active form of tamoxifen (4-hydroxytamoxifen or 4-OHT) as a gel applied to the breast skin in women who needed surgery for DCIS. We found that the 4-OHT gel was as effective as tamoxifen pills in decreasing the growth rate of DCIS cells, suggesting that 4-OHT gel may be substituted for oral tamoxifen in future studies. Particularly important was the fact that very little 4-OHT appeared in the circulation of women in the gel group, raising expectations that 4-OHT gel would cause few side effects and would be more acceptable to women. Additional studies of this approach are now ongoing.


Colon Cancer Prevention in People with Inflammatory Bowel Disease

Myo-inositol is a compound that has shown promise as an anti-inflammatory agent. People with inflammatory bowel disease and abnormal colonic cells are at increased risk for colon cancer.  We found that the use of myo-inositol decreased the molecular changes that are associated with colon cancer risk, and further development of myo-inositol in this setting may therefore be useful.

bottom of page