Intra-arterial Chemotherapy for Spinal Metastases

Overview

Metastatic malignant tumors comprise the vast majority of spinal tumors in adults. The most devastating complication of spinal metastatic disease (SMD) is invasion of the spinal canal and compression of the spinal cord or the nerve roots of the cauda equina, resulting in a clinical entity known as cord compression that manifests with progressive loss of motor function and sensation in the legs, as well as bladder and bowel incontinence. The treatment of spinal metastases is mostly palliative with the goals of improving or maintaining neurologic function, achieving local tumor control, and spinal stability. Most patients with spinal metastatic disease are currently treated effectively with radiation therapy and/or surgery with good results. There are however certain limitations in the current treatment of SMD. Radiation therapy has two important limitations: 1) if the targeted SMD is in close proximity the spinal cord, delivery of high radiation doses is contraindicated as it may cause radiation-induced damage to the spinal cord (myelopathy, and 2) there is limit on the cumulative amount of radiation dose, which means that recurrent tumors may not be amenable to repeat radiation therapy. As far spinal surgery is concerned, the main limitation is that some patients are not fit for surgery because of medical co-morbidities. This phase I clinical research trial will test the hypothesis that a new minimally invasive treatment called spinal intra-arterial chemotherapy (SIAC) can be safely applied in patients with SMD.

To date, there is no effective systemic therapy for spinal metastases, and the goal of treatment is to achieve local control of the tumor. Despite advances in radiation therapy, there is still a subgroup of patients that cannot be effectively treated with radiation because of close proximity of the tumor to the spinal cord. In addition, in cases of recurrent tumors, some patients cannot be re-treated because they reached the maximum allowed radiation dose. Surgery is the alternative treatment for these patients, but some tumors do recur after surgery while some patients have comorbidities that make surgery a high-risk procedure. Based on our prior experience with selective IA chemotherapy for the treatment of ocular retinoblastoma and the high local control rates achieved with selective IA injection of chemotherapy in recurrent limb melanoma (limb infusion and limb perfusion) we expect that spinal intra-arterial chemotherapy with selective injection of Melphalan in the arteries feeding the metastatic disease is feasible and safe and may prove beneficial in achieving local control of the spinal tumor, preventing neurological compromise from cord compression. This minimally invasive approach can be used in patients in whom radiation therapy and surgery are contra-indicated and essentially have no other treatment options.