Children With Soft-Tissue Cancers Face Risk of More Tumors
Survivors treated with chemotherapy and radiation at greater risk, study finds
MONDAY, April 25, 2005 (HealthDay News) -- Many more youngsters are surviving cancer, but at what cost?
A new National Cancer Institute study found that children who were treated for soft tissue sarcomas have a higher risk of developing other cancers when they are older.
Children who were treated with a combination of chemotherapy and radiation were at a particularly high risk for developing second cancers, said the study, which appears in the June 1 issue of Cancer.
"The good news is that you have people living long enough to have complications, because years ago you never did," said Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Clinic Foundation, in New Orleans.
The study adds to a growing body of literature showing that survivors of childhood cancer in general are more likely to suffer from health problems, including subsequent cancers, even as they live longer.
Soft tissue sarcomas are cancers that arise in tissues such as muscles, tendons, fat, nerves and blood vessels. According to the National Cancer Institute, they are relatively uncommon, accounting for less than 1 percent of all new cancer diagnoses each year. In 2000, there were an estimated 8,100 new cases of soft tissue sarcomas in the United States, about 850 or 900 of which were in children and adolescents under the age of 20.
The researchers reported that improvements in cancer treatments over the past 20 years have led to improved survival for children diagnosed with soft tissue sarcomas. There have also been previous reports of an increased risk of later malignancies, but the estimates of risk have ranged from three to 13 times the risk of the general population.
Other studies also involved only small numbers of patients, in contrast to the current study, which looked at data from 1,499 children and adolescents who survived for one year after they had been diagnosed and who were included in the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database.
The survivors of soft tissue sarcomas had about six times the risk of developing a subsequent cancer, compared to the general population, the study found.
Those initially treated with radiation and chemotherapy had a 15 times higher risk of second malignancies, compared to people treated with surgery alone -- they had a 1.4 times higher risk.
In particular, long-term survivors seemed to be prone to develop acute myeloid leukemia, melanoma, breast cancer, oral cavity cancers and sarcomas of the bone and soft tissue, the researchers said.
"Radiation to the breast in young women does increase the risk of having breast cancer," Brooks said. "Today, in the treatment of Hodgkin's disease, we try to avoid radiation at all costs, especially in young women."
Although this level of elevated risk may seem alarming, the study authors cautioned that the absolute risk was still low. Only about 3 percent of children with soft tissue sarcomas would be expected to develop a second cancer within 20 years of the initial diagnosis.
Treatment may not have been the only factor contributing to the increased risk of a second cancer. Childhood soft tissue sarcoma is associated with certain genetic syndromes, including neurofibromatosis type 1 and Li-Fraumeni syndrome, which predispose a person to multiple cancers, the researchers said.
According to the study authors, this was the first report of an association between soft tissue sarcoma and an elevated risk of cancers of the oral cavity. An increased risk of oral cancers and other childhood tumors has been noted, however.
"By doing studies like this we know what the long-term effects are, and we can then devise better treatments to try to avoid them," Brooks said. "For people who have already been treated, we can follow the patients for diseases we can screen for, such as breast cancer."
For more on soft tissue sarcomas, visit the National Cancer Institute.