A Patient-Specific Fracture Risk Assessment Tool for Femoral Bone Metastases: Using the Bone Strength (BOS) Score in Clinical Practice

SIMPLE SUMMARY: Patients with femoral metastases are at risk of developing a fracture, whose prevention is important for maintaining mobility and, hence, patients’ quality of life. The BOne Strength (BOS) score is a computed tomography (CT)-based patient-specific computer model that objectively calculates the bone strength of femurs with metastases. It was developed to aid patients and their treating physicians in selecting appropriate treatment options, either radiotherapy in low-risk femurs or elective stabilizing surgery in high-risk femurs. In this pilot study, the added clinical value of the BOS score in treatment-related decision making was assessed. The study showed that the BOS score is a promising and objective tool to assess fracture risk in femoral bone metastases and aids physicians and patients in making a more informed decision regarding the most appropriate treatment. ABSTRACT: Patients with femoral metastases are at risk of fracturing bones. It is important to prevent fractures in order to maintain mobility and quality of life. The BOne Strength (BOS) score is based on a computed tomography (CT)-based patient-specific finite element (FE) computer model that objectively calculates bone strength. In this pilot study, the added clinical value of the BOS score towards treatment-related decision making was assessed. In December 2019, the BOS score was implemented in four radiotherapy centers. The BOS scores and fracture risks of individual patients were calculated and returned to the physician to assist in treatment decisions. The physicians filled out a questionnaire, which was qualitatively analyzed. A follow-up to identify fractures and/or death was performed after six months. Until June 2021, 42 BOS scores were delivered (20 high, 9 moderate, and 13 low fracture risk). In 48%, the BOS score led to an adaptation of treatment plans. Physicians indicated that the BOS score provided objective insight into fracture risk, was reassuring for physicians and patients, and improved multidisciplinary discussions and shared decision making. In conclusion, the BOS score is an objective tool to assess fracture risk in femoral bone metastases and aids physicians and patients in making a more informed decision regarding the most appropriate treatment.