2523 - Perspectives on Oligometastatic Disease Treatment: A Survey Among Radiation Oncologists and Medical Oncologists

R. Gutt¹, S. Malhotra², S. P. H. Lee³, L. Hoffman-Hogg^4,5, R. Shapiro⁶, G. Wechsler⁷, K. Faricy-Anderson⁸, M. McGunigal⁹, M. D. Kelly¹⁰, and J. Wallach⁹; ¹Washington DC VA Medical Center, Washington, DC, ²The Southeast Permanente Medical Group, Jonesboro, GA, ³University of California, Irvine, Orange, CA, ⁴VHA National Oncology Program, Office of Nursing Services, Washington, DC, ⁵VHA National Program, Durham, NC, ⁶Department of Radiation Oncology, Richard L. Roudebush VA Medical Center, Indianapolis, IN, ⁷VA National Radiation Oncology Program, Richmond, VA, United States, ⁸Providence VA Medical Center, Providence, RI, ⁹Veterans Affairs New York Harbor Healthcare System, New York, NY, ¹⁰National Radiation Oncology Program, Veterans’ Healthcare Administration, Washington, DC

Purpose/Objective(s): Since the initial presentation of the phase II randomized SABR-COMET and “Local Consolidative Therapy vs. Maintenance Therapy/Observation for Oligometastatic Non-Small Cell Lung Cancer” trials at ASTRO in 2018, the paradigm for local treatment for oligometastatic disease (OMD) has evolved. Multiple phase III trials are currently enrolling patients to better understand who benefits from consolidative treatment, particularly radiotherapy (RT). The purpose of this study was to evaluate perceptions and practice patterns among radiation oncologists and medical oncologists regarding use of radiation therapy (RT) for OMD. Materials/

Methods: A 12-question survey was emailed to Veterans Health Administration (VHA) radiation oncologists and medical oncologists. The survey enquired about academic affiliation of respondents; presence of on-site Radiation Oncology; classification of lesion number for OMD; benefit of RT for OMD; if RT is curative for OMD; and if RT should be limited to certain histologies. Three theoretical OMD cases were also presented with treatment options that varied based upon a physicians willingness to address OMD with local RT. Descriptive statistics and chi-square tests were used for data analysis. The impact of specialty and academic affiliation on survey responses was evaluated.
Results: Of the 106 survey respondents, 59 (55.6%) were radiation oncologists and 47 (44.3%) were medical oncologists. All agreed that there is a potential benefit of high-dose RT for appropriately-selected cases. Most (88.7%) responded that RT for OMD contributes to cure (88.1% of radiation oncologists, 89.4% of medical oncologists; p=0.84). Slightly more than half (52.9%) of respondents (55.2% of radiation oncologists, 50.0% of medical oncologists; p=0.60) agreed that local RT for OMD treatment should not be limited by histology. The majority of radiation oncologists classified up to 5 lesions as OMD, whereas the majority of medical oncologists considered up to 3 lesions as OMD (p=0.006). Thirty-six medical oncologists (76.6%) have radiation oncology on-site – this sub-group was more likely to consider local RT potentially curative than peers without radiation oncology on-site (94.4% vs. 72.7%, p=0.04). Statistically significant differences were noted in management of 2 of the 3 clinical cases presented based on academic affiliation.
Conclusion: Survey results demonstrated significant confidence amongst both radiation oncologists and medical oncologists that local RT improves oncologic outcomes. However, there is a difference between radiation oncologists and medical oncologists in how they define OMD, and there are nuances in treatment of sample cases presented. Close collaboration with radiation oncologists influences medical oncologists’ belief in the curative role of RT for OMD. As more phase III data for OMD local treatments emerge, we plan to further investigate how beliefs and practice patterns evolve amongst radiation and medical oncologists.