Prevalence of Malignancies in Patients with Sickle Cell Disease in North Carolina

Introduction: Significant advancements in sickle cell disease (SCD) management in recent decades have increased the life expectancy of patients. While recent studies suggest an increased risk for hematologic malignancies, particularly acute myeloid leukemia (AML), and selected solid tumor malignancies, there is a paucity of data on the prevalence of malignancies in the SCD population. This study reports on the prevalence of hematologic and solid tumor malignancies among individuals with SCD in North Carolina (NC). Methods: The NC hospital discharge datasets, a state-wide all payer dataset inclusive of emergency department visits, hospitalizations, and outpatient surgery visits with discharge dates between January 1, 2013 and December 31, 2020 were used. It is a limited dataset and individuals were linked using date of birth, sex, and zip code. Individuals of all ages were included if they had three or more visits with International Classification of Diseases (ICD) codes for SCD over five years. The prevalence of hematologic and solid tumor malignancies among participants was identified using ICD codes associated with visits. Results: We identified 10,305 individuals with SCD in NC between January 2013 and December 2020 with a mean age of 25.17 years, 46.05 % males and 53.95 % females. During the study period, 271 (2.6%) participants died at a mean age of 45.2 (+/-17.8 SD) years. In total, 312 (3%) participants had concurrent diagnoses of hematologic malignancies and 199 (1.9%) had solid-tumor malignancies reported at least once during this period. Of the 312 patients with hematologic malignancies, there were 23 patients (0.22%) with non-Hodgkin's lymphoma and 23 patients [0.22%] with myelodysplastic syndrome.Among the 199 patients diagnosed with solid-tumor malignancies, there were 41 patients (0.40%) with digestive system tumors and 31 patients [0.30%] with respiratory system tumors. Other more commonly seen tumors were connective tissue tumors (0.28%), male (0.21%), and female (0.22%) genital tract tumors. Conclusion: Our findings suggest a prevalence of myeloid leukemias in SCD patients of almost 0.11%, similar to that reported in England (0.19%) but higher than that reported in California (0.09%). We also report an increased prevalence of GI malignancies (0.40%, 41/10305) similar to previous reports. A significant number of patients (204) carry a diagnosis of essential thrombocythemia which might be an overestimation. This likely represents individuals with thrombocytosis, often seen during acute sickle cell crises. However, the NC hospital discharge is a limited dataset and cannot be linked to the NC cancer registry for further validation. Prevalence of malignancies in our study varies from previously studied populations in California and England in part due to differences in patient demographics and lifestyle exposures. Also, this study relied on ICD codes documented during inpatient, ED or outpatient surgery visits to identify the occurrence of malignancies in the sample which might have undercaptured its actual occurrence by excluding patients who were treated in the outpatient setting. There is certainly a need to further evaluate malignancy risk in this patient cohort in comparison to the general population. A better understanding of the incident risk will allow clinicians to improve surveillance protocols and management of malignancies in this population.