Children who survive bone cancer have a modest risk of developing a second “solid organ” cancer elsewhere in the body later in life, a long-term follow-up study confirms.

The study included more than 2,800 children who were treated for osteosarcoma or Ewing sarcoma, which are cancers of the bone, from 1976 to 2005. Sixty-four percent of patients were alive at the time of the analysis.

During a median follow-up of 6.1 years, 17 patients developed a second cancer a median of 7 years after being diagnosed with bone cancer, Dr. Robert Goldsby of University of California-San Francisco and colleagues report in the journal Cancer.

Compared with a sex- and age-matched general population, the risk of a second solid organ cancer was increased 2.9-fold in patients who had had osteosarcoma and 5-fold in patients who had had Ewing sarcoma.

The estimated 10-year cumulative incidence of second cancers was 1.4 percent for the entire study group, 0.9 percent for osteosarcoma patients, and 1.8 percent for Ewing sarcoma patients.

The “relatively low” cumulative incidence of second cancers may stem from the fact that the cohort has been followed for a fairly short period of time, the investigators say. With increasing follow up, second cancers will likely emerge, “because they typically occur after a latency of 10 to 15 years,” they point out.

Exposure to the chemotherapy drugs etoposide and cyclophosphamide and to radiation significantly increased the risk of second cancers.

The data also indicate that the outcome after development of a second cancer is poor, with a 5-year overall survival rate less than 40 percent.

“The development of improved therapies with fewer long-term consequences is paramount,” Goldsby and colleagues conclude. Follow up of children who survive malignant bone tumors, they say, “should focus on monitoring for both recurrence of primary malignancies and development of second malignant neoplasms.”

SOURCE: Cancer, November 1, 2008.