I've wondered about this for a while. I was in the category of large tumor, close margins, negative nodes. Too big to do a lumpectomy with good cosmetic results. But because of the close (but negative) margins, I also received radiation. I really, really want to see data comparing lumpectomy + rads with mastectomy + rads - as well as MX alone vs MX + rads, for similar tumor characteristics. I don't quite understand why so few people get post-mastectomy radiation given the relatively low risk of side effects with modern radiation treatment.

I feel that lumpectomy+radiation is more appropriate in certain cases then mastectomy, and vice versa. I don't think it can be quite as cut-and-dried as one gives you a better survival advantage than the other; it may be more truthful to say that - under certain circumstances - one may have better results for a certain type of individual depending on mitigating factors.