gms | German Medical Science

Objectives: Long bone metastases are common in patients with renal cell carcinoma (RCC). Considering improved patient survival, metastasectomy and megaprosthetic reconstruction has become a frequently used surgical option. However, patient and implant survivorship as well as types of complications are unclear, particularly considering the competing risk of death. We therefore investigated overall patient survival, types of complicatons leading to revision surgery as well as implant survival. Furthermore, potential associated factors for implant revision were studied.

Methods: Retrospective study from a single center from 1993 to 2017. 86 patients with a RCC long bone metastasis underwent reconstruction with a single-design, modular implant system (Implantcast MUTARS). The most common location of megaprosthetic reconstruction was the proximal femur (PFR) in 38% (33 of 86) of patients followed by 23% (20 of 86) distal femur and proximal humerus reconstructions each.

The mean (±SD) patient age at surgery was 69 years (± 6.8), and 71% (61 of 86) of patients were male. 54% (46/86) of patients presented with a pathological fracture, 31% (27 of 86) had a solitary metastasis and 29% (25 of 86) had undergone previous stabilizing surgery. The mean follow-up period was 53 months (±SD 30) with a minimum follow-up of 24 months for patients who did not undergo revision surgery or died. We calculated overall patient survival and associated factors using the Kaplan-Meier method and implant survivorship using a competing risk analysis with death as a competing event.

Results and conclusion: 73% (63/86) patients died of their disease after a median of 19 (IQR 9–37) months following surgery and a median of 71 (IQR 31–132) months after the initial diagnosis of RCC. The overall survival probability was 29% (95% CI 18–40%) five years after surgery.

The five-year revision free implant survival was 82% (95% CI 72–89). 8% (7 of 86) of patients underwent an exchange of the implant itself. Soft tissue complications were the most common in 12% of patients (10 of 86).

Patients with total bone replacements had a higher risk revision (HR 19.46 (95% CI 6.9–54.9), p<0.01). Furthermore, the revision risk was higher with increasing reconstruction length per mm (HR 1.01 (95% CI 1.01–1.02), p=0.03). There was an increased risk of complications associated with local postoperative radiation treatment (RTX) (HR 2.59 (95% CI 0.96–6.95), p=0.06) while preoperative RTX (HR 1.038 (95% CI 0.34–3.16), p=0.95)

Patients who undergo megaprosthetic reconstruction following the resection of RCC metastases even in historic patient cohorts exhibit decent overall survival necessitating the use of a lasting reconstruction. Modular megaprostheses demonstrated a fairly low risk of implant revision although postoperative radiation therapy and total bone replacements increase that risk.