Humeral metastasis of renal cancer: Surgical options and review of literature.

INTRODUCTION: The humerus is the second most common long bone site of metastatic disease from renal cell carcinomas (RCC) after femur. Surgery has an important role in the treatment of these lesions due to renal cell tumor's resistance to chemotherapy and radiotherapy.

HYPOTHESIS: Prosthetic replacement is an effective and safe solution in treatment of renal humeral metastasis.

MATERIAL AND METHODS: Fifty-six patients affected by RCC bone metastases of the humerus that underwent a surgical reconstruction were rewised. Thirty-five lesions were localized on proximal third, 12 on the shaft, 9 on distal third. Among proximal 29 were treated with resection and endoprosthetic replacement and 6 with plate and cement. Six diaphyseal lesions were stabilized with intramedullary nailing, 5 with plate and cement and 1 with an intercalary prosthesis. Regarding distal lesions, 7 elbow prostheses and 2 plates and cement were used.

RESULTS: The average age was 63years. Metastasis was single in 55% of cases, and in 45% metachronous. A pathologic fracture (PF) occurred in 64% of cases. Only 9% of patients had a mechanical complication, 7% an infection and 5% neurological deficit. A local recurrence occurred in 14% of patients. An implant failure has been observed in 10 patients, 5 for mechanical complications, 2 for infections and 3 for local recurrence; of these 7 were treated with a prosthesis and 3 with plate and cement. The mean value of MSTS score was 64%, 63% and 59% respectively in patients with proximal, diaphyseal and distal humerus metastases.

DISCUSSION: Solitary and metachronous bone metastases have a longer survival. Disease-free interval>2years is another important prognostic factor. Reconstruction with a modular prosthesis is recommended in proximal and distal third. Instead in diaphyseal lesions a closed reduction and fixation with intramedullary locked nailing are preferred. When surgical indications are correctly followed, good oncologic and functional outcomes are obtained, leading to markedly improvement of patients' quality of life.

RETROSPECTIVE STUDY: Level of evidence: IV.