I do think your age as well as stage and grade of cancer are very important considerations before making this decision. I have had ovarian cancer and had a complete hysterectomy and both ovaries removed at age 37. In my opinion, if you are done having children and your doctor feels your estrogen is causing a great cancer risk, then this surgery is a good option. Many women who are carriers of breast/ovarian cancer syndrome genes, opt to have this surgery to reduce their risk of ovarian and breast cancer. Studies have shown that it does reduce your risk. But, it is a very personal decision.
I have had a hard time with surgical menopause. But, so far, I have been able to adjust. I do already have early osteoporosis and it has only been three years since my surgery. It also is terrible for the libido! It does stink to be thrown into menopause and then have so many side effects! But, it is nothing compared to cancer. I am a believer in doing anything possible to stay in remission. Hormones definitely cause many types of breast and ovarian cancer to grow.
It sounds to me like your doctor is more concerned about your estrogen levels in relation to the cancer rather than the size of the fibroid. So, from that standpoint, it seems like a good choice. For peace of mind, you may consider getting a second opinion. Good luck on making your decision!
It would have been nice to know how old you are. I would get a second opinion before I resorted to more major surgery. I would also look into alternative treatments. Find a reputable homeopath and see what they think. If you get your hormones under balance, the fibroids usually shrink. A homeopath or whatever you are guided to will treat the whole body. Sometimes they grow before menopause and then after menopause they will shrink again. Instead of needing less estrogen, you may need more of your other hormones working to balance things out. There may be some under-activity in another area.