Radiation and Medical Oncology Perspectives on Oligometastatic Disease Treatment.

Background: Recent phase 2 randomized clinical trials support the use of aggressive local treatment in addition to systemic therapy for oligometastatic disease (OMD) to improve progression-free survival and overall survival. These studies have mostly incorporated stereotactic body radiotherapy and serve as the foundation for multiple phase 3 trials aiming to determine how many metastases comprehensive local radiotherapy (RT) offer survival benefits, and for which cancers.

Methods: To understand clinician views on the role of local RT for OMD, a 12-question survey was developed that included case examples. The survey was distributed to Veterans Health Administration (VHA) radiation oncologists and medical oncologists.

Results: Of 106 survey respondents, 59 (55.7%) were radiation oncologists and 47 (44.3%) were medical oncologists. All respondents indicated high-dose RT has potential benefits for appropriately selected cases. Most oncologists (88.7%) responded that RT for OMD contributes to cure (88.1% radiation oncologists, 89.4% medical oncologists; P = .84). More than half (52.9%) of respondents (55.2% radiation oncologists, 50.0% medical oncologists; P = .60) indicated that local RT for OMD should not be limited by histology. Most radiation oncologists classified ≤ 5 lesions as OMD, whereas most medical oncologists classified ≤ 3 lesions as OMD (P = .006). Thirty-six medical oncologists (76.6%) has a radiation oncology department at their institution. This subgroup was more likely to consider local RT as potentially curative than peers without radiation oncology at their institution (94.4% vs 72.7%; P = .04). Management differences in the 3 oligometastatic cases were also identified.

Conclusions: The results of this study highlight ongoing support among VHA oncologists for local RT in the management of OMD and reveal specialty-based and access-based variability in treatment perspectives.