Central venous device-related infection and thrombosis in patients treated with moderate dose continuous-infusion interleukin-2

BACKGROUND: This study was performed to determine the incidence of central venous device-related blood stream infection and thrombosis in patients treated with moderate dose continuous-infusion interleukin-2 (IL-2). METHODS: The records of 160 consecutive patients treated at the University of Wisconsin Hospital and Clinics, between June 1990 and June 1997, with moderate dose continuous-infusion IL-2 (IL-2 [1.5-3.0 x 10(6) U/m(2)/day] Hoffman-LaRoche, Nutley, NJ or IL-2 [4.5 x 10(6) U/m(2)/day] Chiron Corporation, Berkley, CA) were reviewed retrospectively. The majority of patients had metastatic melanoma (78 patients) or renal cell carcinoma (70 patients). All of the patients had a surgically implanted central venous device placed before starting IL-2 therapy; 89% of these were cuffed Hickman catheters. Eighty-four patients received 1 mg of warfarin per day as prophylaxis against device-related thrombosis; none received periinsertion prophylactic antibiotics. RESULTS: Twenty-one patients (13%) developed central venous device-related bloodstream infection (DRBSI) during the study period, a rate of 2 DRBSI per 1000 device-days. DRBSIs were associated with the type of immunotherapy given with IL-2 (P = 0.01) and with thrombosis (odds ratio, 4.1; 95% confidence interval, 1.5-11.4; P = 0.008) but not with patient gender, type of cancer, duration of the central device, or site of device placement. Twenty-six patients (16%) developed central venous device-related thrombosis (DRT) during immunotherapy. Low dose warfarin did not appear to prevent thrombosis. Device-related thrombosis was associated with DRBSI but not with patient gender, type of cancer, type of device, duration or location of device, or concomitant immunotherapy. CONCLUSIONS: Central venous DRBSI and DRT are significant complications that can occur during moderate dose continuous-infusion IL-2 therapy. The risk of DRBSI appears lower than the risk reported with high dose IL-2 therapy by previous investigators. The risk of DRT appears to be higher than the risk reported for patients with similar devices but not given IL-2. Low dose warfarin did not prevent DRT when started after device placement.