|Answer:||Most, but not all, breast cancers are oestrogen-positive. Tamoxifen was one of the first drugs used that binds to oestroegen receptors, hence blocking them. While there is some evidence that it reduces the recurrence of breast cancer, the positive effects of the drug wear off after five years. It also increases risk for a number of other problems, including uterine cancer and pulmonary embolism. In one trial where women without breast cancer were divided into a control group and a group given Tamoxifen, fewer of the women on Tamoxifen developed breast cancer, but more of them experienced pulmonary embolism, deep vein thrombosis and strokes. So Tamoxifen can have mild benefits and considerable down sides.
Soya beans contain isoflavones which are weak plant oestrogens. By occupying oestrogen receptors, but not delivering a strong oestrogenic ' message' , these too are touted as protecting against oestrogen dominance. And there is evidence to support this (see ' Why are soya products good as an anti-cancer food?' , page 143.) But since even plant oestrogens could be oestrogenic in excess, I wouldn' t encourage women to eat vast amounts of soya foods.
The relatively low incidence of breast cancer among women in East Asia is likely to be due partly to eating soya, and partly to other positive factors in their diet - more vegetables, garlic and ginger, and less meat and milk, for instance. So my advice is to eat a diet containing soya, but not more than 120z of, say, soya milk and tofu a day. And eat beans, lentils and chickpeas too, as these are good sources of phytoestrogens.
Is a total anti-cancer diet, backed up with supplements, a valid alternative to Tamoxifen? I' d say so.