A preliminary study reveals that fenretinide, a non-toxic drug related to Vitamin A, may significantly reduce recurrent breast cancer in pre-menopausal women. Though researchers say the results need further confirmation, the use of fenretinide in younger women may lead to a new and safe method to prevent breast cancer recurrence. The study, led by Dr. Umberto Veronesi of the Istituto Nazionale Tumori in Milan, found that fenretinide reduces the risk of a second breast cancer in pre-menopausal women by 35%.

Dr. Versonesi and researchers recruited 2972 women between the ages of 30 and 70 years of age who had previously undergone breast surgery for either Stage 1 breast cancer or ductal carcinoma in situ (DCIS) to participate in the trial. The women were randomly assigned into two groups: one group received daily doses of fenretinide for five years while the other group (the control group) did not receive any further breast cancer treatment. After seven years of monitoring the women’s health, researchers discovered 214 cases of a second cancer. Of those 214 women, only 85 had been using fenretinide compared to 129 women who had not taken fenretinide.

Though fenretinide significantly reduced recurrent breast cancer in pre-menopausal women in the trial, the drug showed no benefit in women who had already reached menopause. Dr. Veronesi and researchers are not certain why fenretinide worked well in younger women but believe the effect may be related to the interaction of fenretinide and the female hormone estrogen (a hormone that exists at higher levels in pre-menopausal women). Researchers found that the use of fenretinide by post-menopausal women may actually increase their risk for developing a second breast cancer.

Though fenretinide must undergo additional clinical trials, officials at the National Cancer Institute believe that the preliminary results are promising. Fenretinide has been previously studied as a cancer preventive. Though it is less potent in reducing the risk of breast cancer recurrence than tamoxifen, another drug used to prevent and treat breast cancer, fenrentide has fewer side effects than tamoxifen. The main side effects of tamoxifen include hot flashes, irregular menstrual cycles, vaginal discharge or bleeding, and irritation of skin around the vagina. Currently, women with early stage breast cancer are four to five times as likely to develop cancer in the opposite breast than women who have not had breast cancer.

According to Dr. Veronesi, fenretinide works by imposing order on breast cells that are becoming malignant (cancerous) by growing more disorganized and multiplying out of control. Fenretinide also forces cells that are becoming "dangerously immortal" to undergo normal apoptosis (cell death).⁽¹⁾

In addition to reducing recurrent breast cancer risk in pre-menopausal women, fenretinide also decreased the risk of ovarian cancer.

in younger women in the study. Six cases of ovarian cancer were discovered among the control group (who did not take fenretinide) compared to zero cases among the women on fenretinide. Ovarian cancer is far less common than breast cancer but potentially more deadly.

Additional Resources and References

• (1) The November 3, 1999 NYT Syndicate report, "Nontoxic Drug Shown to Help Reduce Return of Breast Cancer," is available at http://199.97.97.16/contWriter/yhdweek/1999/11/04/medic/8807-0285-pat_nytimes.html
• The November 3,1999 Boston Globe article, "Drug May Reduce Return of Breast Cancer," is available online at http://www.more.com/article.html?itemId=400817.
• The November 3, 1999 Reuters Health report, "Fenretinide's Effect On Risk Of Breast Cancer Recurrence Appears Age Related," is available at http://www.reutershealth.com/.

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