Importance of Cancer Aftercare

Q: I am 72 years old, and have a history of cancer (ovarian and histiocytoma in my leg). Five years ago I had a mastectomy, and I have scar tissue from the surgery. A few months ago I developed pink scar tissue in the area where the staple was pulled out. Within the pink scar tissue a large dark mole came, then another. It oozes occasionally, and at times is painful—usually after I do housework. I have had other large dark moles that eventually fall off, as well as several moles that start out as skin color and itchy, but then turn into dark moles. Should I be concerned about them?