Radiotherapy- and Chemotherapy-Induced Myelodysplasia Syndrome

This study explored which kinds of cancer are related to a higher incidence of subsequent myelodysplastic syndrome (MDS) after radiotherapy (RT) and chemotherapy (CT). We performed a nested case–control study by using data from the Taiwanese National Health Insurance (NHI) system. The case group PhD, Ji-An Liang, MD, and Chia-Hung Kao, MD multivariable logistic regression analysis was conducted, and odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. Overall, cancer patients who received RT or CT exhibited secondary MDS more frequently than did those who did not (RT: OR1⁄4 1.53; 95% CI1⁄4 1.33–1.77; CT: OR1⁄4 1.51; 95% CI1⁄4 1.25–1.82). Analysis by cancer site showed that RT increased the risk of MDS for patients with stomach, colorectal, liver, breast, endometrial, prostate, and kidney cancers. By contrast, CT was more likely to increase the risk of MDS for patients with lung, endometrial, and cervical cancers. Further analysis revealed that RT and CT seemed to have a positive interaction. The major limitation of this study was the lack of certain essential data in the NHI Research Database, such as data regarding cancer stage and treatment dose details. This population-based nested case–control study determined that RT and CT predisposed patients in Taiwan to the development of MDS. This effect was more prominent when both modalities were used. (Medicine 94(17):e737) Abbreviations: AML = acute myeloid leukemia, CI = confidence interval, CT = chemotherapy, ICD-9-CM = International Classification of Diseases, Ninth Revision, Clinical Modification, LHID = Longitudinal Health Insurance Database, MDS = myelodysplastic syndrome, NHIRD = National Health Insurance Research Database, NHRI = National Health Research Institute (NHRI), OR = odds ratio, RT = radiotherapy. INTRODUCTION I n Taiwan, cancer has been the leading cause of death among the general population since 1982. The age-adjusted incidence rate has increased steadily since then; and it reached 320.65 new cases per 100,000 people in 2011. The proportion of long-term cancer survivors is rising owing to successful cancer-screening programs, earlier detection, advanced diagnostic tools, timely and effective treatment, improved follow-up after treatment, and an aging population. Consequently, the surveillance and monitoring of cancer survivors has become a crucial concern, regarding cancer control, as well as the emergence of cancerand treatment-related health problems. Myelodysplastic syndrome (MDS) comprises a heterogeneous group of closely related clonal hematopoietic disorders that are characterized by hypocellular or hypercellular marrow with impaired morphology and maturation and peripheral blood cytopenias, followed by progressive impairment of the ability of myelodysplastic stem cells to differentiate and a tendency to evolve into acute myeloid leukemia (AML). MDS has been identified to be associated with previous cancer treatment by using chemotherapy (CT) or radiotherapy (RT). Treatmentn reported in various cancers, such as dgkin lymphoma, Hodgkin lymphoma, arian cancer, prostate cancer, and brain www.md-journal.com | 1 tumors. Although the absolute number of treatment-related MDS cases is small, the poor prognosis of MDS warrants concern. To the best of our knowledge, no nationwide populationbased study has measured treatment-related MDS for cancer overall and for various individual cancers. We explored this topic in Taiwan. We designed this research to determine, among cancer survivors, which primary sites of cancer were more susceptible to the development of MDS after treatment, and whether CT and RT interact. We used a database from the National Health Insurance (NHI) system of Taiwan to conduct this study.