Utilization of imaging modalities in the staging of newly diagnosed rectal cancer: A survey of U.S. radiation oncologists.

Abstract

564 Background: Accurate staging is crucial for management of patients (pts) with newly diagnosed rectal cancer. Endorectal ultrasound (EUS) has been a commonly used imaging modality for almost two decades, with magnetic resonance imaging (MRI) now preferred by national guidelines. Routine positron emission tomography (PET) is not recommended for initial staging. The current utilization of imaging modalities by radiation oncologists (ROs) in staging newly diagnosed rectal cancer pts in the United States is unknown. Methods: We conducted an anonymous IRB-approved online survey of practicing U.S. ROs. Respondent characteristics were tested for association with self-assessed utilization of imaging modalities using Chi-squared test. Staging 75% of more rectal cancer pts with a given modality was defined as high utilization. Results: We received 220 responses from practicing U.S. ROs. Among the responders, 85 are academically affiliated and the majority specialize in treating GI malignancies, with 98 seeing more than 10 rectal cancer pts annually. Most respondents utilize all three imaging modalities for rectal cancer staging - EUS, MRI and PET/CT. Fifty two percent and 38% of respondents are high utilizers of EUS and MRI, respectively. Nearly half (47%) of respondents are high PET utilizers. High utilization of PET was associated with practice in a private setting (p < 0.05) and being within 10 years from residency training completion (p < 0.05). Conclusions: Our analysis reveals a wide discordance between national guidelines and the practice patterns among U.S. ROs, with underutilization of MRI and overutilization of PET/CT. Substantial cost savings could be realized by following national guidelines recommendations to omit the routine use of PET/CT in the initial evaluation of pts with rectal cancer.