Amid a challenging battle with cancer, actress Shannen Doherty has shared a hopeful update on her health journey. The actress spoke about her experience on her most recent podcast. Shannen Doherty, known for her roles in “Beverly Hills, 90210” and “Charmed,” has been undergoing a new cancer infusion treatment. After an uncertain start, the 52-year-old has revealed a significant breakthrough. “After the sixth and seventh treatment, we really saw it breaking down the blood-brain barrier,” Doherty said. “Do I call that a miracle? For me, that happens to be a miracle right now.” The actress attrib…