Butches, you need to get tested for all the womanly cancers -- even if you don't feel womanly. Cancer doesn't care if you are butch; you can still get breast cancer. Do those self exams. See your doctor.
It's a question we still can't answer, because too many researchers just don't think to ask study participants about sexual orientation, and because there hasn't been much money put into research that specifically focuses on the LGBT community's health.