Practice Patterns for Postoperative Radiation Therapy in Patients with Metastases to the Long Bones: Survey of the Japanese Radiation Oncology Study Group

Background: Because of the lack of evidence on practice patterns of postoperative radiation therapy (PORT)in patients with metastases to the long bones, it is essential to characterize the current practice patterns and identify factors affecting dose-fractionation to aid future clinical trials. MethodsThe palliative radiation therapy subgroup of the Japanese Radiation Oncology Study Group conducted an internet-based survey to determine the prescription practices and various dose-fractionations used for PORT. Additionally, responders were asked to recommend dose-fractionations in four hypothetical cancer cases, wherein each case represented a patient with impending pathological fractures and one of the four features: limited prognosis, solitary metastasis, radio-resistant primary tumor, or long-term survival. Responders were asked to indicate their preferred irradiation fields and the reasons for choosing long-course radiotherapy over short-course radiotherapy (RT). ResultsEighty-nine radiation oncologists from 67 institutions and 151 RT plans were included. Twenty-two different dose-fractionations were used; the most commonly used and recommended dose-fractionation was 30 Gy in 10 fractions. “Local control” was most the common reason for preferring longer course RT. While fractionated higher-dose regimens were preferred in case of oligometastasis, low dose regimens were preferred in case of limited prognosis; single fraction RT was never preferred. Most respondents recommended involvement of “the entire orthopedic prosthesis.” ConclusionFor PORT of metastases to the long bones, 30 Gy in 10 fractions for the entire orthopedic prosthesis is preferred in current practice. Oligometastasis and a limited prognosis influence the selection of high- and low-dose regimens, respectively. Single fraction RT is never preferred.