Adverse events in cancer patients with sickle cell trait or disease: Case reports

Purpose: Given the relatively high prevalence of sickle cell trait and disease among African Americans and established racial disparities in cancer outcomes, we reviewed the literature regarding adverse events in cancer patients with these hematologic genotypes. Erythrocyte sickling can result from extreme hypoxia and other physiologic stressors, as might occur during cancer therapy. Further, tumoral hypoxia, a poor prognostic and predictive factor, could lead to a cycle of local sickling and increased hypoxia. Methods: A search of PubMed produced 150 publications, most of which were excluded because of incidental relevance. Eleven case reports of patients diagnosed from 1993 to 2013 were reviewed. Results: Two reports of patients with sickle cell trait describe an abundance of sickled erythrocytes within tumors, and a third report describes sickling-related events requiring multiday hospitalization. Eight reports of patients with sickle cell disease delineated multiorgan failure, vaso-occlusive crises, and rapid renal deterioration. Hypothesized triggers are delayed clearance of anticancer agents attributable to baseline kidney damage, activation of vasoadherent neutrophils from treatment to counter chemotherapy-induced neutropenia, hypoxia from general anesthesia, and intratumoral hypoxia. Conclusion: Clinical implications include pretreatment genotyping for prophylaxis, dose adjustment, and enhanced patient monitoring. With the current lack of high-quality evidence, however, the scope of poor outcomes remains unknown.