11-year-old boy beats cancer — twice

Pedro Martinez, 11, rings the bell to signify his recovery from cancer, outside the Michigan Children’s Hospital in Detroit on November 6, 2020. He was diagnosed with Acute Lymphoblastic Leukemia in 2017 and started receiving chemotherapy. Shortly after, he experienced a relapse and received a bone marrow transplant from his father. (Antranik Tavitian/Detroit Free Press/TNS)

Pedro, 11, and his parents Leticia and Juan Martinez, watch cars filled with family and friends drive by after he rang the bell to signify his recovery from cancer, outside the Michigan Children's Hospital in Detroit on November 6, 2020. He was diagnosed with Acute Lymphoblastic Leukemia in 2017 and started receiving chemotherapy. Shortly after, he experienced a relapse and received a bone marrow transplant from his father. (Antranik Tavitian/Detroit Free Press/TNS)

Pedro, 11, and his mother, Leticia Martinez, watch cars filled with his family and friends drive by after he rang the bell to signify his recovery from cancer, outside the Michigan Children's Hospital in Detroit on November 6, 2020. He was diagnosed with Acute Lymphoblastic Leukemia in 2017 and started receiving chemotherapy. Shortly after, he experienced a relapse and received a bone marrow transplant from his father. (Antranik Tavitian/Detroit Free Press/TNS)

Pedro Martinez, 11, left, celebrates with nurses during a ceremony to signify his recovery from cancer, outside the Michigan Children’s Hospital in Detroit on November 6, 2020. (Antranik Tavitian/Detroit Free Press/TNS)

DETROIT — There is a tradition in pediatric oncology centers across the country. When a child is done with cancer treatment, they can ring a ceremonious bell, surrounded by friends, family and hospital staff.