Prediction of Long Bone Fractures in Multiple Myeloma Patients in an Advanced Imaging World.

Background Multiple myeloma (MM) affects the long bones in 25% of patients. The advent of positron-emission tomography/computed tomography (PET/CT) scanners offers the possibility of both metabolic and radiographic information and may help determine fracture risk. To the best of our knowledge, no published study correlates these two factors with long bone fractures. Objectives To evaluate the impact of PET/CT on fracture risk assessment in multiple myeloma patients. Methods We identified all bone marrow biopsy proven multiple myeloma patients from 1 January 2010 to 31 January 2015 at a single institution. We prospectively followed patients with long bone lesions using PET/CT scan images. Results We identified 119 patients (59 males/60 females) with 256 long bone lesions. Mean age at diagnosis was 58 years. The majority of lesions were in the femur (n=150, 59%) and humerus (n=84, 33%); 13 lesions in 10 patients (8%) required surgery for impending (n=4) or actual fracture (n=9). Higher median SUVmax was measured for those with cortical involvement (8.05, range 0-50.8) vs. no involvement (5.0, range 2.1-18.1). SUVmax was found to be a predictor of cortical involvement (odds ratio = 1.17, P = 0.026). No significant correlation was found between SUVmax and pain or fracture (P = 0.43). Conclusions Improved medical treatment resulted improvement in 8% of patients with an actual or impending fracture. The orthopedic surgeons commonly use the Mirels classification for long bone fracture prediction. Adding PET/CT imaging to study in myeloma long bone lesions did not predict fracture risk directly but suggested it indirectly by cortical erosion.