ARRS 2022 Abstracts

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1221. FDG-PET/CT Cancellation in Patients with Diabetes
Authors * Denotes Presenting Author
  1. Mohit Bansal *; Brown University/Rhode Island Hospital
  2. Grayson Baird; Brown University/Rhode Island Hospital
  3. Don Yoo; Brown University/Rhode Island Hospital
  4. Elizabeth Dibble; Brown University/Rhode Island Hospital
Objective:
This study aims to determine the FDG-PET/CT cancellation rate in patients with diabetes; compare the cancellation rates in patients with diabetes by medication, exam time, age, and gender; and calculate the average delay of care and cost to institution caused by exam cancellation. FDG-PET/CT is an essential tool in the workup of many cancers as well as many infectious and inflammatory conditions. The examination relies on the administration of the radiotracer fluorodeoxyglucose (FDG), a glucose analog. There is a well-known association between plasma glucose levels, serum insulin levels, and their effect on the biodistribution of 18F-FDG. Patients should have a blood glucose level <200 mg/dL to undergo FDG-PET/CT, and patients with diabetes must adhere to strict medication administration instructions prior to FDG-PET/CT examination to prevent a nondiagnostic exam. For these reasons, patients with diabetes are at high risk for exam cancellation, which results in a delay in care and increased cost to the healthcare system due to unused radiopharmaceutical dose.

Materials and Methods:
This study was IRB-approved and HIPAA-compliant. A retrospective review of patients with diabetes who presented for FDG-PET/CT at a tertiary cancer center from 7/1/2020 - 3/24/2021 was performed. Demographic information, type of medication, and time of examination (AM or PM) were prospectively collected as part of an ongoing quality project and retrospectively analyzed for the current study. Data were analyzed by using logistic regression and Kaplan-Meier estimation with SAS 9.4.

Results:
A total of 1707 FDG-PET/CT exams were completed during the study period, 117/1707 (6.9%) in patients with diabetes; 132 patients with diabetes presented for exams (excluding eight repeat presentations for previously cancelled exams). The cancellation rate in patients with diabetes was 17.4% (23/132), 18.2% (4/22) if on oral medication and insulin, 26.7% (8/30) if on insulin only, 10.7% (8/75) if on oral medication only, and 33.3% (1/3) if on no medications, p=.12. The median delay to repeat presentation was 7 days (95% CI [4, 9]). The first 25% returned within 4 days (95% CI [1, 6]). The maximum delay was 30 days. Of the 23 cancellations, 3 did not return to our center for imaging. No differences in can cellation rates were observed when examining gender, time of exam, or medications (p > .10). The approximate cost of an FDG dose is $200; therefore, the institutional cost of unused radiopharmaceutical dose during the study period was approximately $4600.

Conclusion:
Patients with diabetes who presented for FDG-PET/CT exam had a high cancellation rate and median delay in care of 7 days. There was a trend toward higher cancellation rate in patients on insulin and patients not on medication. Cancelled exams cost the institution approximately $4600 in unused radiopharmaceutical during the study period. Results of this study suggest areas for targeted interventions to decrease cancellation rate, save money, and allow for timely delivery of care.