Children fighting cancer. Part 3, Olivia and Zakk.

The third in a four-part series following nine children as they fight childhood leukemia. This part looks at 3-year-old Olivia and 13-year-old Zakk who both have the most common form of leukemia - acute lymphoblastic leukemia. The methods of treating this kind of leukemia have improved greatly since the 100% death rate in the 1950s to the now nearly 90% survival rate. Olivia is being treated at Great Ormond Street hospital and is currently in remission. We follow her treatment follow-ups after the initial one month intensive chemotherapy treatments and also explore her relationship to her twin sister who so far shows no sign of developing leukemia. Zakk's leukemia is initially resistant to the initial intensive chemotherapy and is put on the most aggressive chemotherapy treatment available for children which has very unpleasant side effects. Professor Mel Greaves says that "leukemia is the paradoxical price we have to pay for controlling infections early in life." Both children in this episode make a full recovery although Olivia is left blind in one eye due to an episode of shingles during the latter part of her treatment and the family have to live with the worry that twin sister Isabella will also develop leukemia.