In the largest study yet, it was found that childhood cancer survivors are at a high risk of developing new tumours as they age.
The research involved 14,358 individuals enrolled in the federally funded Childhood Cancer Survivor Study (CCSS).
St. Jude Children's Research Hospital investigators leading the effort reported that 1,382, or 9.6 percent, of survivors developed new tumours unrelated to their original cancers.
About 30 percent of those survivors, 386 individuals, developed third tumours. Four or more tumours were found in 153 survivors in this study.
"These findings show that when you describe adult survivors of childhood cancer it is not sufficient to describe their risk of a first subsequent cancer, but to acknowledge that some of these patients are at risk for multiple cancers," Gregory Armstrong, M.D., the study's principal investigator and an assistant member of the St. Jude Department of Epidemiology and Cancer Control, explained.
"This is the first study to more fully enumerate that risk," he said.
The work underscores the importance of cancer screenings for this growing population.
For example, mammograms beginning at age 25 rather than age 40 are recommended for female survivors whose childhood treatment included chest radiation of 20 grays or more. A gray is a measure of absorbed radiation.
"These survivors are candidates for additional genetic evaluation to look for an underlying genetic propensity for tumour development or an inability to protect healthy cells against the harmful effects of radiation," Armstrong said.
The findings have been published in the June 27 online edition of the Journal of Clinical Oncology.