The vast majority of survivors of childhood cancer do not develop new tumours. Over the decade after a child is declared cured - meaning there is no recurrence in a five-year period - his or her risk of developing a new cancer is less than 2 percent. Said another way, that means if we follow 100 of these kids for 10 years, we would see only two new cancers.
Harsh radiation and chemotherapy treatments that kill all cells, good and bad, are increasingly being replaced with more gentle, targeted therapies aimed specifically at eradicating tumour cells. Most doctors have dropped radiation altogether for Hodgkin's disease, one of the most common childhood cancers. Among the new approaches are less toxic chemotherapy drugs that target the cancer cells and so-called monoclonal antibodies that selectively seek out and destroy tumour cells, gene-based therapies and vaccines that use the immune system to attack and eradicate cancer cells.
However, people who survive cancer in childhood have six times the expected risk of developing new cancers by the time they are in their 30s. Children who received radiation were at greater risk for new cancer than those who were treated with drugs or surgery. Young girls treated with radiation for leukaemia, brain tumours or soft tissue cancers faced a risk of breast cancer in the next 20 years that is 16 times higher than normal.