Childhood cancer survivors at increased risk of sarcoma

Survivors of childhood cancers have a ninefold increased risk of developing a secondary sarcoma - a cancer of connective or supportive tissue such as bone, fat, or muscle - compared with the general population, according to a study in the February 21 Journal of the National Cancer Institute.

Treatments for childhood cancer have resulted in a current overall cure rate of over 70 percent. However, long-term survivors of childhood cancer are at a higher risk of developing a secondary cancer than the general population. Previous studies have shown that these survivors are specifically at a higher risk of secondary sarcomas, such as soft tissue sarcomas and osteosarcoma. Radiation therapy is associated with secondary sarcomas, but other specific risk factors are largely unknown.

Tara Henderson, M.D., of the University of Chicago Department of Pediatrics, and colleagues examined the incidence of secondary sarcomas and the risk factors associated with that risk among the 14,372 participants in the Childhood Cancer Survivor Study. Overall, there were 751 second cancers diagnosed among the participants, 108 of which were secondary sarcomas such as soft tissue sarcoma, malignant peripheral nerve sheath tumors, and osteosarcoma. These sarcomas were diagnosed an average of 11 years after patients were diagnosed with their primary cancer.

The authors found that patients with secondary sarcomas were more likely to have received primary radiation therapy; to have received higher doses of drugs called anthracyclines or alkylators; to have had a primary diagnosis of soft tissue sarcoma, bone tumor, or Hodgkin lymphoma; to have a family history of cancer; or to have a history of other second cancers. The risk of a secondary sarcoma was ninefold higher among childhood cancer survivors than the general population. The authors calculated that the excess number of cases of secondary sarcomas among childhood cancer survivors over those in the general population is 32.5 cases per 100,000 person-years of follow-up.

"As the childhood cancer survivor population ages and expands in number, clinicians and researchers must carefully identify patients who are at risk for secondary morbidities, particularly for secondary cancers," the authors write. "Diagnosis of a sarcoma can sometimes be elusive because symptoms are often nonspecific."
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Journal of the National Cancer Institute