How To Avoid Developing A Secondary Cancer ?

I am 43 and at 41 had ER+/PR+ HER2- breast cancer. Had mastectomy, chemo and radiation and put on tamoxifen. Now cancer has metastasized to bones. Currently started Eligard shots, Zometa, switched to Arimedix, also told to take Vitamin D and Calcium. My oncologist suggests removal of my ovaries. I wondered if I should have uterus and cervix out also. My mom passed away from Endometrial Cancer at age 60. I was told her cancer and mine not related. My breast cancer will not go to my uterus it will go other places. I tested negative for HPV so I was told no chance of cervical cancer, had uterine biopsy and all is healthy there. I was told my personal decision and I have to do what will make me sleep at night but my doctors say all is needed is ovaries to come out that to have hysterectomy is not medically necessary and will not change my survival changes at this point-which is 2-3 years since it is in my bones. I am so confused what would be best for me an oophorectomy or hysterectomy, I want to do best medically for me and what will help me live as long as I can without the worry of developing a secondary cancer somewhere else.