Invasive Fungal Disease in Patients with Chronic Lymphocytic Leukemia in Japan: A Retrospective Database Study

Invasive fungal disease (IFD) is an important cause of morbidity and mortality in patients with hematological malignancies. As chronic lymphocytic leukemia (CLL) is a rare hematological malignancy in Japan, IFD incidence in Japanese patients with CLL is unclear. This study aimed to investigate IFD incidence in Japanese patients with CLL. This retrospective cohort study used data of patients with CLL registered between April 2008 and December 2019 in the Medical Data Vision database (n = 3484). IFD incidence after CLL diagnosis in the watch-and-wait (WW) and drug therapy (DT) groups was 1.5% and 9.2%, respectively. The most common type of IFD was invasive aspergillosis (28.1%). Cox proportional hazards multivariate analysis revealed that DT (hazard ratio [HR]: 2.13) and steroid use (HR: 4.19) were significantly associated with IFD occurrence. IFD incidence was significantly higher in the DT group than in the WW group (log-rank p < 0.001); however, there was no significant between-group difference in the time to IFD onset or the type of IFD (p = 0.09). This study determined the incidence of IFD in patients with CLL during WW. Physicians should monitor for IFD, even among patients with CLL undergoing the WW protocol.