Results from the Childhood Cancer Survivor Study (CCSS) show that current advances in treatment and follow-up have led to improved survival of childhood cancers, including lymphoma, especially by reducing deaths due to lingering effects of cancer treatment. The study, performed at St. Jude Children’s Research Hospital, was published in the online edition of the New England Journal of Medicine.
The extensive study looked at 34,033 children and adolescents diagnosed with cancer between 1970 and 1999. All participants were considered long-term survivors, living at least five years following diagnosis.
The results show that the death rate — particularly the 15-year death rate — among young cancer patients has decreased significantly since 1970, partly because of a reduction in treatment-related health complications. Data from 1970-74 and 1990-94 showed a decline from 12.6 percent to 6 percent among patients. Deaths due to secondary complications of treatment also decreased, from 3.5 percent to 2.1, percent during those time periods.
Since 1970, pediatric cancer care and follow-up treatment went through important changes. Reduction in exposure to anthracycline chemotherapy, and reduced use and dose of radiation therapy for the treatment of acute lymphoblastic leukemia (ALL) and Hodgkin lymphoma also led to a decreased rate of complications, such as secondary cancers and heart failure.
The percentage of ALL survivors treated by brain irradiation over the study’s 29 years decreased from 86 percent to 22 percent.
In a press release, the principal investigator of the CCSS study, Gregory Armstrong, said: “This study is the first to show that younger survivors from more recent treatment eras are less likely to die from the late effects of cancer treatment and more likely to enjoy longer lives. The results are a testament to the physicians and scientists who in the past 30 years took a calculated risk of developing new protocols that used less intense therapies that reduced the risk of late effects and maintained excellent five-year survival.”
The biggest difference in death rates were observed for patients diagnosed with standard-risk ALL, Hodgkin lymphoma or Wilms tumor (a kidney cancer) as their primary cancer. According to the American Cancer Society, five-year survival for pediatric patients with these cancers is now 90 percent or better.
Heart disease-related death decreased for survivors of ALL and Hodgkin lymphoma. These patients were also less likely to be treated with radiation therapy or anthracyclines.
According to the release, St. Jude published evidence in 2009 that pediatric ALL is curable without brain irradiation, and the hospital no longer uses such radiation treatment. It reports that 94 percent of its ALL patients now live at least five years post-diagnosis.
The percentage of Hodgkin lymphoma patients treated with radiation fell from 96 percent to 77 percent — a change also accompanied by a decrease in the mean cumulative anthracycline dose given these pediatric cancer patients. “For CCSS, the next question is what is the quality of life and health that childhood cancer survivors enjoy during their extended life span,” Dr. Armstrong said.