I would let your oncologist know about the severity of your postmenopausal symptoms. I know that there are some types of anti-depressants that can relieve some of the symptoms and that sleeping pills can also help as well. I am also going through 'surgical' menopause and it can be tough at times!
I was told that I could NOT take over the counter supplements for menopausal symptoms. They believe that my masses were estrogen receptive...that means no soy, no black cohash, etc as they all "mimic" estrogen.
I used folic acid and black cohosh for my symptoms. I really only had hot flashes and night sweats and using folic acid and black cohosh seemed to lessen the frequency and severity for me. This combination doesn't work for everybody. Check with your doctor before taking these supplements because they can intefer with some prescription medicines...especially for thyroid problems. Julie
Soy has plant estrogens. If your cancer is estrogen sensitive I would be very careful about using any product with "isolated soy protein."