Image-guided helical Tomotherapy for treatment of spine tumors

One of the most common indications for radiotherapy is treatment of the spine. The vast majority of cases are related to metastatic disease with primary tumors of the spine being rare. Conventional radiation therapy often plays an important role in the management of spine tumors although at times with significant side effects and disadvantages. Furthermore, retreatment of spine tumors is a challenge due to concerns over spinal cord toxicity. In this series, we examine the efficacy of using image-guided helical Tomotherapy and the possible advantages offered by this new technology.

Eight patients at Hoag Memorial Hospital Presbyterian were treated between November 2005 and November 2006. The median age was 66 years. Of the eight patients, seven had metastatic disease with one patient having a primary neuroendocrine tumor of the spine. Five patients were previously treated to the spine with conventional radiation planning. Two patients received single fraction stereotactic radiosurgery (15 Gy) while the remaining patients received hypofractionated stereotactic radiotherapy to a median total dose of 2,500 cGy in 500 cGy fractions.

At the time of last follow-up, radiographic control was seen in all eight patients with a median local control rate of 2.5 months (range of 1-5.8 months). Four of the eight patients are still alive with median overall survival of 5.1 months (range 1.4-6.9 months). Acute toxicity ranged from Radiation Therapy Oncology Group (RTOG) score 0-2 and no patients experienced late complications of radiation myelitis.

The TomoTherapy Hi-ART system can be an alternative treatment option for upfront or retreatment of spine tumors. Minimal acute and late toxicity were seen in patients treated with Tomotherapy. Intensity-modulated radiation delivery combined with megavoltage CT image guidance offered by the TomoTherapy Hi-ART system allows for set-up and delivery accuracy that is required for stereotactic treatment of spine tumors and eliminates the need for any internal or external fiducial marker placement.