Abstract 3725: Subsequent gastrointestinal cancer risks of childhood and early adulthood cancer survivors
Authors: Liu Jason J. , Morton Lindsay M. , Berrington de González Amy , Inskip Peter D. , Curtis Rochelle E. 
Published: August 2015

Abstract
Introduction: The number of childhood/early adulthood cancer survivors has been growing due to improved cancer treatment, but subsequent malignant neoplasms (SMN) in the digestive system are an important cause of morbidity and mortality. Few studies have examined these survivors’ risks of developing various subsequent primary gastrointestinal (GI) cancers. In addition, although there have been SMN studies exclusively on Hodgkin lymphoma (HL) survivors, none have compared the GI cancer risks of young HL survivors with that of other young first primary cancer survivors. We used the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program registries to perform the largest analysis on the risks of developing various GI cancers in childhood/early adulthood cancer survivors.
Methods: Among the patients reported to 9 SEER registries from 1973 to 2010, there were 28,858 children/young adults diagnosed with first primary cancer before 21 years of age and survived a minimum of 5 years. From these survivors, 103 GI SMNs were included in this analysis, of which 39 developed from 3,330 HL survivors. Standardized incidence ratios (SIR) were calculated using age-, sex-, race-, and calendar year-matched SEER incidence rates.
Results: Relative to the general population, childhood/early adulthood cancer survivors had significantly higher risks of developing GI cancers (N = 103, SIR = 3.6, 95% CI: 2.9-4.3), esophageal cancer (N = 7, SIR = 7.0, 95% CI: 2.8-14.4), stomach cancer (N = 15, SIR = 5.6, 95% CI: 3.1-9.2), pancreatic cancer (N = 15, SIR = 5.9, 95% CI: 3.3-9.7), and colorectal cancer (N = 41, SIR = 2.5, 95% CI: 1.8-3.4). HL survivors had 6.8-fold higher risk of developing GI cancers (N = 39, 95% CI: 4.9-9.3), whereas survivors of other first primary cancers had 2.8-fold higher risk (N = 64, 95% CI: 2.1-3.5) (P-homogeneity&lt;0.001). Those who received radiation treatment without chemotherapy for first primary cancer had 4.8-fold higher risk of developing GI cancers (N = 31, 95% CI: 3.2-6.8), with 8.1-fold higher risk for HL survivors (N = 23, 95% CI: 5.1-12.1) versus 2.2-fold higher risk for survivors of other primary cancers (N = 8, 95% CI: 1.0-4.3) (P-homogeneity&lt;0.001).
Conclusion: Childhood/early adulthood cancer survivors have significantly higher risks of developing GI cancers relative to the general population, with particularly high risks for upper GI sites and HL survivors. These novel findings may contribute to the clinical follow-up guidelines for young cancer survivors.
Citation Format: Jason J. Liu, Lindsay M. Morton, Amy Berrington de González, Peter D. Inskip, Rochelle E. Curtis. Subsequent gastrointestinal cancer risks of childhood and early adulthood cancer survivors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3725. doi:10.1158/1538-7445.AM2015-3725