Kypho-Iort: A Novel Treatment Of Spinal Metastases With Intraoperative Radiotherapy During Kyphoplasty

Vertebral column is the most prevalent location of bone metastases. Patients with instable and painful spinal metastases receive surgery for stabilization followed by fractionated radiotherapy over 2-4 weeks to control the underlying malignant process. Many patients with bone metastases simultaneously present visceral metastases and require urgent systemic therapy. However, due to increased toxicity, concurrent chemotherapy and irradiation is rarely possible. We have therefore established a novel method for intraoperative radiotherapy (IORT) during kyphoplasty which enables immediate stability, sterilization of the metastasis and immediate initiation of chemotherapy. The kyphoplasty conformed to standard procedure with minor modifications. For intraoperative radiotherapy the INTRABEAM system (Carl Zeiss Surgical, Oberkochen, Germany) was used. After choosing a bipendicular approach specially designed metallic sleeves were inserted to guide the drift tube of the INTRABEAM system. Correct position of the sleeves was verified using biplanar X-rays. Then the applicator (including the drift tube) was guided through the sleeve into the center of the metastasis. There a single dose of 8 Gy in 5 mm distance using 50 kV x-rays was delivered within 2 minutes. After removal of the INTRABEAM system the kyphoplasty balloon was inflated and PMMA cement was injected. The total treatment lasted less than 90 minutes. Since August 2009 14 lesions in 12 patients were treated. There were five males and seven female patients with a median age of 65, 5 years. The primary histological diagnoses included: breast cancer (6), prostate cancer (2), rectum cancer, lung cancer, gastric cancer and hepatocellular carcinoma (respectively 1). No radiation induced skin reaction or neuropathy was seen. There were only a few procedure-related complications in two patients (asymptomatic extravertebral cement leak, asymptomatic pulmonary cement extravasation). Pain improved in all patients on day one. To date there have been no local failures with a median follow-up of two months (> 6 months in 2 patients). The combination of kyphoplasty and IORT is technically feasible with high patient acceptance. As survival in patients with cancer increases this new treatment method may become a valuable option for patients with spinal metastases providing immediate stability and sterilization of the metastasis.