Long-term mortality from second malignant neoplasms in 5-year survivors of solid childhood tumors: temporal pattern of risk according to type of treatment.

BACKGROUND

The temporal pattern in mortality from late second malignant neoplasms in solid childhood cancer survivors, according to the type of treatment, has not been investigated in detail.

METHODS

We studied 4,230 5-year survivors of solid childhood cancer diagnosed between 1942 and 1986 in France and the United Kingdom. Complete clinical, chemotherapy, and radiotherapy data were recorded and the integral radiation dose was estimated for 2,701 of the 2,948 patients who had received radiotherapy.

RESULTS

After a median follow-up of 28 years, 134 fatal events were due to second malignancies, compared with the 13.3 expected from the general France-UK population rates. The standardized mortality ratio was of a similar magnitude after radiotherapy alone and chemotherapy alone and higher after both treatments. The standardized mortality ratio decreased with follow-up, whereas the absolute excess risk increased significantly over a period of at least 25 years after the first cancer. This temporal pattern was similar after chemotherapy alone, radiotherapy alone, or both treatments. We observed a similar long-term temporal pattern among survivors who had died of a second malignant neoplasm of the gastrointestinal tract and breast. Survivors who had received a higher integral radiation dose during radiotherapy were at a particularly high risk, as well as those who had received alkylating agents and epipodophyllotoxins.

CONCLUSIONS

Five-year survivors of childhood cancer run a high long-term mortality risk for all types of second malignant neoplasms whatever the treatment received and require careful long-term screening well beyond 25 years after the diagnosis.