I was diagnosed with DCIS in my left breast in July, 2008. I wanted a double mastectomy and reconstruction from the outset. I saw three different breast doctors, and one thought that anything more than a lumpectomy and radiation was overkill.
The doctor whom I chose to do my surgery asked me why I wanted a bilateral mastectomy. I gave him my reasons: (1) I was in good health and very strong right now, and there was no guarantee that if I had a recurrence after a lumpectomy or a single mastectomy, that I would be as strong as I am now, (2) I didn't want radiation, which would be required with a lumpectomy, (3) I did not want to take tamoxifen, which I was told I would need to take if I had any breast tissue, since my tumors were estrogen and progesterone receptive (I have no ovaries so that was not an issue), (4) if I had a single mastectomy, the reconstruction process would involve cutting into the other breast to make them symmetrical, and (5) I was currently employed and had health insurance. He thought they were all good reasons and he agreed to do the double mastectomy.
The pathology came back and we were all shocked to find out that they found invasive lobular cancer (.07 cm) in my prophylactic breast (in addition to lobular cancer in-situ in both breasts that was undetected), which never showed in any of the mammograms or sonograms. My doctor says that this is rare, but I tell this story because it was such an amazing validation on my insistence for the double mastectomy which basically saved my life. My sentinel nodes were clean (both sides were biopsied).
Follow your gut and your heart. I did and it saved my life.