Breast Cancer Prevention

In the last column we asked: Can we prevent breast cancer? The answer is NO! Can we reduce the risk of breast cancer? The answer is YES!

The risk of breast cancer can be reduced by use of medications, surgery and change in lifestyle. Let us first discuss the use of medication – tamoxifen.

The risk of breast cancer is related to levels of hormones present in the body from internal and external sources, says a review article in the New England Journal of Medicine written by Dr. Rowan Chlebowski, Harbor-UCLA Medical Centre, California. Tamoxifen is a medication that blocks the action of oestrogen on tissues. Most breast cancers are oestrogen dependent. And tamoxifen has been found to reduce recurrence of breast cancer in 47 percent of patients who have had breast cancer previously.

Tamoxifen has also been found to reduce the risk of breast cancer in the other breast by 47 percent regardless of the oestrogen dependence of the initial tumour. If this is the case then it was felt that tamoxifen might also reduce the risk of breast cancer in women who have no personal history of the same.

This hypothesis was tried for four years on 13,388 women, with no personal history of breast cancer but with an above average risk. Tamoxifen reduced the overall odds of breast cancer in these women by 50 percent. Unfortunately, the same results were not obtained from the trials in Britain and Italy. Probably, the trials had different designs.

It is not certain whether tamoxifen helps improve mortality, how long should it be used, and once stopped then how long the benefit will last. There is no evidence that more than five years of therapy results in further benefit. Keeping this in mind, the Food and Drug Administration in US has approved the use of tamoxifen for the reduction of breast cancer risk on women at increased risk of this disease.

Use of tamoxifen is not without risk. It is generally very safe but in rare instances can cause cancer of the uterus, blood clots, hot flashes, vaginal discharge etc. Tamoxifen should not be taken for prevention of breast cancer without first discussing with an oncologist.

What about surgery?

Prophylactic removal of both breasts is a reasonable option only for women identified as being at very high risk for breast cancer who are willing to consider its long-term implications, says Dr. Chlebowski. It is an irreversible procedure, there is loss of nipple sensation, and cosmetic and aesthetic results may not always be satisfactory. In one study, removal of both breasts resulted in reducing the calculated odds of breast cancer and associated death by about 90 percent. This is pretty good.

Second surgical option is to have both ovaries removed before menopause. Observational studies have suggested that this may reduce the risk of breast cancer by 22 to 50 percent. But further studies are required to prove that this a good option of premenopausal women at high risk for breast cancer who have decided not to have children or not to have more children, says Dr. Chlebowski.

Finally, lifestyle changes and risk reduction. Increased dietary fat intake, body weight, and alcohol intake and decreased exercise have been associated with increase breast-cancer risk, says Dr. Chlebowski. Improving in all these areas will certainly help in overall improvement of health.

Sometimes medicine has been described as imperfect science. What you read today is a good example. There are no clear-cut answers, but there some options which may help some women. I guess that is better than no options! So discuss this with your doctor or an oncologist before you decide what is good for you.

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