Risk Factors and Impact on Survival of Pathological Fractures in Patients With Humeral Metastasis

Background Bone metastases often cause pathological fractures and impair patients' quality of life and survival. Although several studies have been conducted on pathological fractures in the femur and spine, limited research has been done on the upper limbs. This study aimed to reveal the risk factors and determine how pathological fractures impact survival in patients with humeral metastasis. Methods This retrospective study was based on patients with humerus metastasis treated in the Nagoya-City University Hospital from 2010 to 2020. Patient characteristics, including sex, age at diagnosis of humeral metastasis, primary cancer, prior treatment, anatomical location, and metastatic lesion size, were retrieved from medical records. The patients were divided into pathological fracture and non-fracture groups, and their backgrounds and survival rates were compared. Results Of the 31 patients with 32 metastatic lesions included in this study, 19 had pathological fractures (one patient had bilateral fractures) and 12 had no fractures. Our analysis revealed that the risk factors for pathological fracture were treatment without bone-modifying agents, treatment without radiotherapy, and larger circumferential cortical involvement. The median overall survival was 21 months; 1-year survival was 56% in the non-fracture group and 59% in the fracture group. There was no significant difference in survival rates between the two groups and only chemotherapy correlated with longer survival in multivariate analysis. Conclusions Bone-modifying agents have the benefit of preventing pathological fractures due to humeral metastases. The humeral pathological fracture did not affect the patient's survival, and chemotherapy was the only prognostic factor that prolonged survival.