Second malignant neoplasms after childhood cancer: A nationwide population-based study in Korea.

Hee Young Ju,Jiwon Lim,Hyeon Jin Park,Eun-Kyeong Moon,Hee Young Shin,Byung Kiu Park,Young-Joo Won,Samir M Dalia

doi:10.1371/journal.pone.0207243

Hee Young Ju, Jiwon Lim + Show 6 more

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https://doi.org/10.1371/journal.pone.0207243

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Abstract

BackgroundSecond malignant neoplasm is one of the most devastating late effects of childhood cancers. This study aimed to evaluate the incidence and survival outcomes of patients developing second malignant neoplasms (SMNs) after surviving childhood cancer in Korea.MethodsMedical data of childhood cancer patients diagnosed between 1993 and 2012 were obtained from the Korea Central Cancer Registry. The risk of developing SMNs was calculated using standardized incidence ratio (SIR), excess absolute risk (EAR), and cumulative risk. Kaplan-Meier survival curves were estimated, stratified by SMN status.ResultsA total of 28,405 childhood cancer patients were diagnosed in the study period, and 337 (1.2%) developed SMN. The total follow-up period was 197,359 person-years at risk (PYR), with a median follow-up duration of 5.6 years. Overall SIR was 20.0, which was 23.2 in women, and 17.6 in men. The overall EAR was 16.4 per 10,000 PYR. The most common types of SMNs, in order of incidence, were other malignant epithelial neoplasms, leukemia, and soft tissue sarcomas. The cumulative incidence of developing SMNs was 0.7% at 5 years, 1.2% at 10 years, and 2% at 15 years. After primary cancer diagnosis, the 10-year overall survival rate of patients with SMNs was 65.1%, which was lower than the 73.4% in patients without SMN. After SMN diagnosis, the 10-year overall survival rate was 55.8%.ConclusionThrough this registry-based study of 5.6 years of follow up, childhood cancer survivors were found to be at 20-fold higher risk of developing a malignant neoplasm compared to the general population. The majority of malignant neoplasms are malignant epithelial neoplasms, leukemia, and soft tissue sarcomas. Continued surveillance for assessing long-term risks, and guidance for appropriate long-term follow up of childhood cancer survivors, are needed.

Highlights

Over the past two decades in Korea, the incidence of childhood cancer has increased substantially
The 10-year overall survival rate of patients with second malignant neoplasms (SMNs) was 65.1%, which was lower than the 73.4% in patients without SMN
After SMN diagnosis, the 10-year overall survival rate was 55.8%. Through this registry-based study of 5.6 years of follow up, childhood cancer survivors were found to be at 20-fold higher risk of developing a malignant neoplasm compared to the general population

Summary

Introduction

Over the past two decades in Korea, the incidence of childhood cancer has increased substantially. A recent nationwide childhood cancer study in Korea showed that the age-standardized incidence rate for all cancers among children aged 0 to 14 years was 134.9 per million children in 1999–2011 [1]. The survival rate of childhood cancer has increased [1], which may be a result of improved treatment and health infrastructure [2]. The increase of childhood cancer survivors has resulted in a substantial increase in the incidence of second malignant neoplasms (SMNs) after childhood cancer [3]. This study aimed to evaluate the incidence and survival outcomes of patients developing second malignant neoplasms (SMNs) after surviving childhood cancer in Korea

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