Association between itch and cancer in 16,925 patients with pruritus: Experience at a tertiary care center

Background: Pruritus has been associated with cancer. However, limited data are available on the types of underlying malignancies associated with pruritus. Objective: We sought to characterize the association between pruritus and different cancer types, as well as variations by racial group. Methods: Cross-sectional study of patients ≥18 years of age seen at the Johns Hopkins Health System during 2013-2017. Patients with pruritus were compared with patients without pruritus. Analyses were stratified by race. Results: Patients with pruritus were more likely to have concomitant malignancy than those without pruritus (odds ratio 5.76, 95% confidence interval 5.53-6.00). Most strongly associated were cancers of the liver, gallbladder and biliary tract, hematopoietic system, and skin. Compared with white patients, black patients more frequently had soft tissue, dermatologic, and hematologic malignancies and less frequently had liver, respiratory, gastrointestinal, and gynecologic malignancies. Limitations: The cross-sectional design precludes analysis of the temporal association between pruritus and malignancy. The study is limited to a single tertiary care center. Conclusion: Pruritus is most strongly associated with cancers of the liver, skin, and hematopoietic system. Black patients with pruritus have a higher likelihood of skin, soft tissue, and hematologic malignancies than white patients, while whites have higher likelihoods of liver, respiratory, gastrointestinal, and gynecologic malignancies.