Presenter(s)
R. Ingebritsen1, F. Al-Doori2, C. Clemens3, R. Hutten1, S. Perlman3, and J. M. Floberg4,5; 1Department of Human Oncology, University of Wisconsin Hospitals and Clinics, Madison, WI, 2University of Wisconsin Hospitals and Clinics, Madison, WI, 3Department of Radiology, University of Wisconsin Hospitals and Clinics, Madison, WI, 4University of Wisconsin School of Medicine and Public Health, Madison, WI, 5Department of Human Oncology, University of Wisconsin-Madison, Madison, WI
Purpose/Objective(s): Treatment interruptions during Lutetium-177-PSMA-617(Lu-PSMA-617) therapy have been reported in up to 15% of patients and can lead to misallocation of resources. We sought to characterize treatment interruptions at our institution, quantify the resulting number of wasted doses, and estimate their financial impact to inform future quality improvement efforts.
Materials/Methods: We performed a retrospective analysis of all patients who experienced a treatment interruption resulting in a wasted Lu-PSMA-617 dose from January 2024 to December 2025. Manual chart abstraction captured demographic data, laboratory values preceding cancellation, interruption reason, and treatment course. Interruption categories included toxicity/laboratory abnormalities, acute illness, disease progression, decompensation, or logistical factors.
Results: Our analysis included 38 patients; the median age was 78 years (IQR 71–82) with a median Karnofsky Performance Status of 80 (IQR 70–80). Of 472 planned infusions, 12% (n=56) were wasted because of treatment interruptions. Cancellations occurred a mean of 2 days before the scheduled infusion (range 0–9). The most common reason for interruption was toxicity/laboratory abnormalities (52%, n=29), followed by acute illness (34%, n=19), decompensation (7%, n=4), progression (5%, n=3), and weather-related cancellation (2%, n=1). Among interruptions due to toxicity/laboratory abnormalities, cytopenias accounted for 83% (n=24). At the time of cancellation, mean hemoglobin was 9.4 ± 1.4 g/dL, mean absolute neutrophil count was 2441 ± 1638/µL, and mean platelet count was 116 ± 60 K/µL. Most patients (61%, n=23) who had a dose withheld did not receive further therapy and ultimately discontinued treatment due to decompensation (56%, n=13), progression (22%, n=5), or toxicity (22%, n=5). A minority (24%, n=9) received 1–4 additional doses before discontinuing therapy prematurely. Only 16% (n=6) completed the full treatment course. During the study period, the wholesale drug price increased from $45,517.50 to $49,677.80. The 56 wasted infusions represented $2,643,774.82 in total drug cost with a weighted average cost of $47,210.26 per missed dose. These expenses were credited back to the institution, and patients were not billed.
Conclusion: Treatment interruptions during Lu-PSMA-617 therapy are common, often lead to premature discontinuation, and result in significant dose waste. Cytopenias were the predominant cause of treatment interruption, and most patients who had a dose cancelled did not resume therapy. The associated financial burden of treatment interruption is substantial. These findings highlight opportunities for quality improvement initiatives focused on toxicity mitigation, laboratory monitoring, patient selection, and resource stewardship.