Renal Cancer Metastasis to the Spine

Epidemiology and Presentation

Bone metastases occur in 30-40% of patients with advanced renal cell carcinoma (RCC), with the spine being the most frequent site of skeletal involvement 1
Bone metastases most frequently occur in the spinal column; postmortem examinations have demonstrated that spinal metastases are present in approximately 70% of patients with cancer 2, 3
More than 50% of spinal metastases are secondary tumors from breast, lung, or prostate carcinomas, with renal cell carcinoma also being a common primary source 2, 3

The American Urological Association recommends prompt neurological cross-sectional CT or MRI scanning of the head or spine in patients with a history of renal neoplasm presenting with acute neurological signs or symptoms 4, 5
A bone scan is recommended in patients with an elevated alkaline phosphatase, clinical symptoms such as bone pain, and/or if radiographic findings are suggestive of a bony neoplasm 4, 5
Routine bone scans are not recommended in the absence of elevated alkaline phosphatase, bone pain, or suggestive radiographic findings, as the prevalence of bony metastases in asymptomatic patients is very low (less than 1%) 4, 5

The NCCN Panel recommends imaging tests such as CT or MRI before starting systemic treatment/observation; subsequent imaging may be performed every 6 to 16 weeks as per physician discretion and patient's clinical status 1
Additional imaging such as CT or MRI of the head or spine, and bone scan should be performed at baseline and then as clinically indicated 1
The imaging interval frequency should be altered according to rate of disease change and sites of active disease 1

Stereotactic body radiation therapy (SBRT) is associated with favorable rates of local control (approximately 90% at 1 year) and complete pain response (approximately 50%), with low rates of serious adverse events 6
Bisphosphonates such as zoledronic acid or RANK ligand inhibitors (denosumab) are recommended for patients with bony metastases to reduce skeletal morbidity and prolong time to bone lesion progression 1
The NCCN Panel recommends supportive care as a mainstay of therapy for all patients with metastatic RCC, including surgery for patients with oligometastatic disease whose disease is well-controlled extracranially 1