Outcomes and prognostic factors after surgery for bone metastases in the extremities and pelvis: A retrospective analysis of 140 patients.

Background: Surgical therapy of bone metastases is becoming increasingly important due to prolonged life expectancy and improved oncological treatment options. In a mostly palliative approach, it is necessary to identify those patients who might benefit from surgery. The shorter the remaining lifetime, the more restricted the indication and the less radical the intervention should be. The aim of this study was to evaluate the postoperative outcomes and prognostic factors for survival of patients with surgically treated bone metastases. Methods: We retrospectively included 140 patients who underwent surgery for 151 bone metastases in the extremities and pelvis at our hospital between 2010 and 2020. We examined patient demographics, surgical procedures, 30-day complications, local tumour progression, and reoperations. Survival was calculated using Kaplan-Meier analysis. Prognostic factors were investigated by univariate analysis using the log-rank test and multivariate analysis using the Cox regression hazard model. Results: In 138 patients, the median survival time was 12.3 months. The overall survival rates at one, two, three and five years were 52.3%, 37.6%, 28.0%, and 18.0%, respectively. In univariate analysis, lung cancer, renal cell carcinoma, pathological fracture, visceral metastasis and multiple bone metastases were significantly associated with prognosis. No significant influence was determined for gender, age, location of bone metastasis, type of surgical procedure and time between diagnosis of primary tumour and surgery for bone metastasis. Multivariate analysis confirmed that pathological fracture, visceral metastasis and lung cancer were negative prognostic variables in terms of survival. Within 30 days, the incidence of complications was 25.0% and mortality was 9.3%. The most common complications were urinary tract infections (5.0%), pneumonia (4.3%), and delirium (2.9%). Local tumour progression occurred in 12 patients (8.7%) and five reoperations (3.6%) were performed. There were no significant differences between patients treated with endoprosthetic replacement (n = 47) and those treated with internal fixation (n = 91) in terms of 30-day complications and mortality as well as local tumour progression. Conclusions: Survival of patients after surgery for bone metastases in the extremities or pelvis is very limited. The presence of a pathological fracture, visceral metastasis and lung cancer were independent prognostic factors for poor survival. Both internal fixation and endoprosthetic replacement achieved similar outcomes.