Original Article

Second Malignant Neoplasms in Survivors of Childhood Cancer

Ray Merrill and Arielle Sloan
World Journal of Epidemiology and Cancer Prevention 2014, 3:3

Abstract

Introduction

 Individuals who survive a first primary cancer in childhood are at increased risk of a second neoplasm.

Study design

This cohort study updates a previous report with 10 additional years of data to verify and add to our existing knowledge about subsequent cancer risk.

Materials and Methods

Analyses are based on a cohort of 40,337 children (age<20 years) who survived cancer for at least two months from 1973 through 2010 in the Surveillance, Epidemiology, and End Results (SEER) program. Each member of this cohort was followed for an average of 17.6 years. Observed/expected ratios based on cancer rates in the general population were calculated based on primary and second primary cancer types and with/without radiation treatment.

Results

Follow-up of the cohort identified 1,081 second malignant neoplasms, which represented a 4.2-fold increase in incidence compared with the general population (O/E=4.2, 95% CI=4.0-4.5). O/E ratios for subsequent cancer were consistently lower than in the first study, with the exception of Hodgkin’s lymphoma. The study also found a heightened risk of esophageal, cecum, corpus uteri, and kidney cancers among Hodgkin’s lymphoma survivors, increased risk for salivary gland tumors among CNS patients, and increased risk of the oral cavity and pharynx, respiratory system, and soft tissue second primaries among bone cancer survivors. O/E risk of subsequent neoplasm was higher among radiation-treated individuals in the current sample than in the original study

Conclusion

The increased risk and latency periods for second malignant cancer among childhood cancer patients depends on the cancer type and treatment, but risk of subsequent cancer lowers over time.

Keywords

Childhood cancer, radiotherapy, secondary neoplasms, subsequent malignancies, treatment

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