(CNN) Shannen Doherty has shared an update on her battle with stage 4 breast cancer, telling Elle magazine that she's trying to "treasure all the small moments" in her life. Doherty said Piro explained that she would have to undergo "hormone therapy to block the estrogen fueling her cancer, plus a second targeted drug that is often effective at stabilizing metastatic disease." "The small things are magnified for me. Doherty said she's been reflecting on her life, asking herself if she has good karma and wondering about the end. "I was like, 'OK, do I have good karma?