The weight gain is probably not technically a side effect of the drugs, but the treatment may be responsible. Hormone receptor drugs cause an estrogen-depleted state. Our bodies need estrogen to survive - not just for reproductive purposes, but for healthy skin, bones, and other processes. When our endocrine system perceives that there is not enough estrogen, it tries to find a work-around. One of the ways our bodies make estrogen is through fat cells - the more fat we have, the more estradiol we will produce. Therefore, if your system was trying to produce more estradiol to make up for estrogen loss otherwise, your metabolism may have been slowed and other processes changed so as to cause weight gain.
Many women find that they gain a lot of weight after a hysterectomy. For many years drs have poo-pooed this as just an emotional reaction and dysfunctional coping after surgery. Thank goodness there are now medical professionals who are beginning to realize and accept that there is a very real physiologic reason for this weight gain, and are attempting to help women cope with estrogen depletion through natural therapies. 15 pounds over 4 months is distressing; the average over a period of several years seems to be about 50 pounds.
So, in one way, your weight gain could be seen as an encouraging thing - if your body is perceiving itself to be in an estrogen depleted state, then the hormone receptor therapy is very effective at depriving any cancer cells in your body of estrogen.
As for reining in the weight gain, the thing that would help most - supplementing with natural phytoestrogens - is the one thing you shouldn't do, because it negates the hormone receptor therapy. If the weight gain is the major thing that is bothering you, and you are otherwise doing well on treatment, then I recommend you step up some other things to keep your weight where it is now and not gain anymore. Drink lots and lots of pure, fresh water (steam-distilled or reverse-osmosis-filtered are best.) This will help regulate your metabolism. Add exercise to your routine - at least 20 minutes 3 - 4 times a week of an aerobic exercise. Walking or swimming are fine choices. Use detoxifiers, like green or black tea - they help eliminate toxins in the blood stream that can contribute to a sluggish metabolism. Increase your intake of antioxidants - a supplement called SOD (superoxide dismutase) is an excellent choice for that. Make sure you are getting plenty of B vitamins, especially vitamin B12.
Watch your dietary intake of processed foods. A diet based on raw, fresh produce (organic when possible) is best. Animal foods slow down the digestive tract, and contribute to weight gain. Unless you are already vegetarian or vegan, best to limit to 3 -4 ounces of meat, poultry or fish 3 -4 times a week. Raw milk is best; if you can't get it or don't like it, try to get milk from grass-fed dairy cows that aren't given any growth hormones. The same with butter and cheese. Eggs should be from free range chickens that aren't given hormones or antibiotics. For sweetener use stevia, crystallized fructose, or small amounts of 100%pure honey or 100% maple syrup. Make sure to get a good intake of essential fatty acids - they play a very important role in both metabolism, the immune system, the endocrine system, and fighting cancer. (A handful of roasted pumpkin seeds will give you all the omegas you need for one day, plus lots of good vegetable protein. recipe: http://motherearthtreasurechest.blogspot.com/2008/09/roasted )
Last, but by no means least, cut out all partially-hydrogenated or fully-hydrogenated fats from your diet. Our bodies cannot digest/metabolise these, but rather than eliminating them, they are stored as fat, because the body has hope that maybe some other day they can be accessed for energy and digested/metabolised then. Just doesn't ever happen - everything we eat in the way of hydrogenized fats follows the old rule: "once across the lips, always on the hips." The best oils to use are cold-pressed or expeller pressed organic olive oil, or expeller pressed 100% pure coconut oil from fresh coconuts as opposed to dried chopra. Both olive oil and coconut oil promote metabolism while providing wonderful cancer-fighting nutrients to the body.
I wish you great success in your treatment, and a wonderful holiday!
Sincerely,
Tre