Skeletal Related Events are Rare After Radiation Treatment for Metastatic Disease of the Femur

Abstract

Background: Pain is a common presenting symptom in patients with metastatic disease to the femur (MDF), and it is often difficult to differentiate pain from the tumor itself versus pain from an impending pathologic fracture. Radiation therapy (RT) is commonly used in the management of pain secondary to MDF but is not adequate in isolation when the underlying bone is structurally compromised.

Questions/ purposes: The purposes of this study were to determine 1) the incidence of skeletal related events (SREs) following RT to the femur, 2) the frequency and implications of orthopedic evaluation prior to RT, and 3) the frequency of patients presenting with a pathologic fracture.

Methods: A retrospective, single-institution review of 86 patients with MDF treated with RT from 2005 to 2018 was performed. Patient demographics, primary cancer type, pathologic fracture, orthopedic interventions, and RT details were assessed. Patients were followed to evaluate the occurrence of skeletal related events of the femur until death or time of last recorded clinical follow-up.

Results: In our cohort of 86 patients, the mean RT dose was 22.3 Gy (8-55.8 Gy) delivered over 6.5 fractions (1-31 fractions). Fifteen patients (17%) received RT less than one month, 30 (35%) less than three months, and 49 (57%) less than six months prior to death. Prior to RT, 42 patients (48.9%) had an orthopedic evaluation, 16 of which (38.1% of those evaluated) received prophylactic stabilization with an intramedullary nail (IMN). Ten patients (11.6%) presented with a pathologic fracture. Following RT, five patients (5.8%) had at least one SRE. Three patients sustained a pathologic fracture, three required repeat RT, and three required further surgical intervention.

Conclusion: Metastatic disease of bone is a common condition that affects many cancer patients. In our institution's series of MDF treated with RT, we only found one patient who sustained a pathologic fracture after RT treatment with an unrecognized impending fracture. As only half of the patients were referred for an orthopedic evaluation prior to RT, continued education of medical and radiation oncologists regarding the signs and symptoms of impending pathologic fracture is warranted.Level of Evidence: IV.

Keywords: bone metastasis; femur; pathologic fracture; radiotherapy.