Childhood Cancer Survival Study Provides Data about Long-Term Prognosis
Childhood cancer survivors are nine times as likely as the general population to develop a sarcoma - a cancer of connective or supportive tissue such as bone, fat, or muscle - according to a study released today by the Journal of the National Cancer Institute, but indicators can help physicians in knowing who's most at risk.
With data from more than 14,000 childhood cancer survivors treated between 1970 and 1986, the Childhood Cancer Survivor Study (CCSS) is believed to be the largest of its kind to date. Tara Henderson, a pediatric oncologist/hematologist at the University of Chicago Comer Children's Hospital, led a study investigating the risk factors associated with developing second sarcomas among the participants of the CCSS.
Today the cure rate for childhood cancer is approaching 80 percent. The survival rate for childhood acute lymphoblastic leukemia alone approaches 90 percent. When deciding upon therapies, physicians need a better understanding of the long-term effects of cancer treatments.
"A generation ago, a pediatric cancer diagnosis was a death sentence," Henderson said. "A new generation is coming of age. Finally, we can see the effects of therapy on growing bodies.
"The hope with this study is that we can learn which patients are predisposed to secondary cancers," she said. The researchers identified factors that increased the risk of developing secondary sarcoma. Those factors include:
- High doses of anthracyclines or alkylators, two types of chemotherapy
- Previous radiation exposure
- Age at the time of primary diagnosis
- Type of cancer
Cancer survivors who are highest at risk for secondary sarcoma are those who were first diagnosed with soft tissue or bone sarcomas, renal tumors or Hodgkin lymphoma.
The study combined data from 26 institutions across the United States and Canada. Out of the 14,372 participants, medical records and pathologic reviews identified 104 independent secondary sarcomas. Four of the 104 developed tertiary sarcomas.
The median age of secondary sarcoma diagnosis was 20 years with a median age for primary diagnosis at 11 years.
Doctors should be very vigilant when caring for a childhood cancer survivor, Henderson said. "They should investigate [a complaint] more quickly--order imaging or blood work as appropriate."
The study confirmed a direct correlation between radiation therapy and the development of secondary sarcomas. The study also found that some survivors who did not have radiotherapy also developed secondary sarcomas.
Sarcomas are more difficult than other cancers to detect because they can occur anywhere in the body. Secondary cancers are the second leading cause of death among 5-year childhood cancer survivors. The leading cause of death among cancer survivors is a relapse of the primary cancer.
Henderson emphasized the importance of early screening for survivors of pediatric cancer. "It's important for childhood cancer survivors to have regular follow-up appointments with physicians who have knowledge of childhood cancer and its late effects so the patients can be appropriately screened."