By Alicia Armeli
Each year, 400,000 people in the US alone suffer from bone metastases.1 Frequently seen in the spine—and specifically in the vertebrae—spinal tumors make up 40% of all bone metastatic disease.2,3 Pain associated with this condition can be excruciating.
Merit Medical’s STAR™ Tumor Ablation System (Spinal Tumor Ablation with Radiofrequency)—a unique device designed for the palliative treatment of painful metastatic spinal tumors—has been found to significantly reduce patient reported pain, often decreasing the need for pain medications, and improving overall quality of life.3,4
Historically, treating patients with metastatic spinal tumors has been a challenge. Traditional pain management is a balancing act that involves pain control, local tumor control to avoid neurological damage, and mechanical stabilization to preserve function.2 Treatments include pain medicines, chemotherapy, radiation therapy, and/or surgery. However, surgery may be avoided due to coexisting health problems or diminished life expectancy.3
A minimally invasive alternative that has been found to successfully treat spinal metastatic lesions is targeted radiofrequency ablation with the STAR Tumor Ablation System. Recognized in version 2014 of the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines for Adult Cancer Pain as an interventional strategy for treatment of local bone pain, radiofrequency ablation can provide rapid pain relief by localized tumor destruction—often in a single outpatient session.5
Anchala et al. conducted a multicenter retrospective study of the STAR Tumor Ablation System involving 92 patients with a total of 128 metastatic spinal lesions from five academic centers who underwent targeted radiofrequency ablation between March 2012 and March 2013.3 Results published in Pain Physician Journal reported all 96 procedures to be technically successful without complication or thermal injury. Average Visual Analogue Scale (VAS) Scores showed that reported pain reduced significantly from 7.51 out of 10 before the procedure to 1.73 post-procedure, which stayed consistent at 6 months (1.75).
What’s more, the authors noted that 54% of the patients participating at the largest center were able to decrease their pain medication dosage. At the same center almost two-thirds of the lesions treated with the STAR Tumor Ablation System were located in the posterior vertebral body—a location previously considered difficult to access. Post ablation images confirmed the size of ablation zones matched those measured with device feedback and showed no further growth or canal extension of treated tumor.
Also significant to note, the STAR Tumor Ablation System was able to treat these patients without having to interrupt their primary cancer treatment. “For late-stage cancer patients, extreme back pain due to spinal tumors degrades quality of life; and until now, limited minimally invasive procedural options for immediate pain relief have been available,” said Nam D. Tran, MD, PhD, a neuro-oncology surgeon at Moffitt Cancer Center, Assistant Professor of Oncology and Neurosurgery at the University of South Florida College of Medicine in Tampa, Fla., and co-author of the study. “This multi-center study validates t-RFA (targeted radiofrequency ablation) as a treatment option that provides rapid, lasting pain relief without the need to interrupt the patient’s primary cancer therapy.”6
The STAR Tumor Ablation System procedure begins with a small puncture at the desired access site and the SpineSTAR® device is inserted into the affected vertebra by way of a working cannula. Active steering capability of the ablation instrument allows for precise navigation through the pedicle and into the desired areas of the vertebra-containing tumor. Once in place, radiofrequency energy is emitted through a bipolar electrode resulting in thermal necrosis of the adjacent tissue while two thermocouples on the electrode simultaneously monitor the tissue temperature. This real time feedback gives physicians the control to create site-specific ablation zones. The radiofrequency energy administration is stopped once the proximal thermocouple measures 50°C . When clinically indicated, the SpineSTAR device allows for precise repositioning within the vertebral body to produce overlapping ablation zones.
An advantage radiofrequency ablation therapy has is that it’s effective on its own and can also be used in conjunction with other treatments. Whether this means patients can continue their prescribed cancer regimen uninterrupted—as noted in the aforementioned study—or as part of a synergistic approach to pain management, ablation has the advantage of flexibility. Coupling pain management therapies can benefit patients with pain that’s hard to manage using traditional forms of treatment, such as radiation therapy.
Although a conventional course of radiation therapy delivered over a series of days to weeks is considered standard care for persistent pain, it has its drawbacks. Statistics show that approximately 60% of patients obtain partial pain relief and only 32% of patients respond with complete palliation.7 Additionally, pain relief following radiation therapy isn’t immediate and can take several weeks.2 Moreover, radiation treatment does have dosage limits. Once dose thresholds of the adjacent normal tissue, such as the spinal cord in the case of spinal metastatic lesions, have been met, recurrent pain at a previously treated site often can’t be retreated.2
A previous feasibility study suggested that combining radiation and ablation therapies may work together to achieve better outcomes compared to using each as a standalone treatment.8 The effect of combined treatments on metastatic spinal tumors was recently reported by Greenwood et al. who carried out a retrospective study, which analyzed medical records of 21 patients with 36 metastatic spine lesions—including radioresistant tumors—treated with the combination of radiation therapy and targeted radiofrequency ablation using the STAR Tumor Ablation System between March 2012 and June 2014.2
Post-procedure outcomes showed patient reported pain measured with the numerical rating scale (NRS) to decrease significantly from an average 8 out of 10 pre-treatment to 4.3 at 1-week and 2.9 at 4-weeks post-treatment. Opioid pain medication use also reduced in 62% of the patients and general activity level increased in 81% of patients at a 4-week follow-up. Post-procedural imaging showed stable treated disease in 12 of 13 and 10 of 10 patients at 3- and 6-months, respectively.
Based on these findings, the authors considered it effective to use ablation and radiation therapies together to treat pain in patients with metastatic spinal lesions and could be an option for those with radiation resistant tumors.
From its start in 1992 treating a handful of patients with benign bone tumors, radiofrequency ablation therapy transformed into an established method of treating metastatic bone disease.3
Almost two decades later in 2012, following FDA 510(k) clearance, DFINE Inc. introduced a percutaneous radiofrequency ablation device purpose built for the palliative treatment of spinal metastatic lesions. Acquired by Merit Medical earlier this year, DFINE Inc. and its unique line of medical devices—including the STAR Tumor Ablation System—are now a part of Merit’s growing portfolio of state-of-the-art oncology products.
It’s estimated that half or more of cancer patients may experience bone pain.1 Metastatic bone lesions are exceedingly common among these individuals and have been found to be the most prevalent cause of chronic pain in this population.3 These tumors have been seen in up to 80% of cancer patients at the time of death, with spinal metastases occurring in about 50% of these cases.3
The STAR Tumor Ablation System can be an option for these patients by offering rapid relief and improved quality of life.4 “If you look at a lot of the treatments that are used [to treat metastatic spine tumor pain], quality of life and life expectancy are not included. And they should be factored in,” explained Jack Jennings, PhD, MD, Diagnostic Radiologist, Associate Professor of Radiology at the Washington University School of Medicine, and Director of Musculoskeletal and Spine Interventions at Mallinckrodt Institute of Radiology in St. Louis, Mo. “Daily we physicians see these patients suffering with pain that has dramatically affected the life they have left.”9
- Smith, H. (2011). Painful osseous metastases. Pain Physician, 14(4): E373-405. http://www.painphysicianjournal.com/linkout?issn=1533-3159&vol=14&page=E373
- Greenwood, T., Wallace, A., Friedman, M., Hillen, T., Robinson, C., & Jennings, J. (2015). Combined ablation and radiation therapy of spinal metastases: a novel multimodality treatment approach. Pain Physician, 18(6): 573-581. http://www.painphysicianjournal.com/current/pdf?article=MjQ1Mg%3D%3D&journal=92
- Anchala, P., Irving, W., Hillen, T., Friedman, M., Georgy, B., Coldwell, D., Tran, N., Vrionis, F., Brook, A., & Jennings, J. (2014). Treatment of metastatic spinal lesions with a navigational bipolar radiofrequency ablation device: a multicenter retrospective study. Pain Physician, 17(4): 317-327. http://www.painphysicianjournal.com/current/pdf?article=MjEyOA%3D%3D&journal=83
- Bagla, S., Sayed, D., Smirniotopoulos, J., Brower, J., Neal Rutledge, J., Dick, B., Carlisle, J., Lekht, I., & Georgy, B. (2016). Multicenter prospective clinical series evaluating radiofrequency ablation in the treatment of painful spine metastases. CardioVascular and Interventional Radiology, 39(9): 1289-1297. doi: 10.1007/s00270-016-1400-8. https://www.ncbi.nlm.nih.gov/pubmed/27343124
- National Comprehensive Cancer Network. (2016). NCCN Guidelines. Retrieved October 18, 2016 from https://www.nccn.org/professionals/physician_gls/f_guidelines.asp
- Merit Medical Systems Inc. (2014). Press Release: Multi-Center Trial Shows Significant Pain Relief For Spine Cancer Patients Following Targeted Radiofrequency Ablation Treatment. Retrieved October 20, 2016 from, https://www.merit.com/category/press-release/
- Sze, W., Shelley, M., Held, I., & Mason, M. (2004). Pallation of metastatic bone pain: single fraction versus multifraction radiotherapy – a systematic review of the randomised trials. The Cochrane Database of Systematic Reviews. (2): CD004721. https://www.ncbi.nlm.nih.gov/pubmed/15106258
- Di Staso, M., Zugaro, L., Gravina, G. L., Bonfili, P., Marampon, F., Di Nicola, L., Conchiglia, A., Ventura, L., Franzese, P., Gallucci, M., Masciocchi, C., Tombolini. V. (2011). A feasibility study of percutaneous radiofrequency ablation followed by radiotherapy in the management of painful osteolytic bone metastases. European Radiology, 21(9): 2004-2010. doi: 10.1007/s00330-011-2133-3. https://www.ncbi.nlm.nih.gov/pubmed/21533865
- Merit Medical Systems Inc. (2016). STAR™ Tumor Ablation System. Retrieved October 17, 2016, from https://www.merit.com/interventional-oncology-spine/spine-ablation/ablation/star-tumor-ablation-system/
Alicia Armeli is a Freelance Writer and Editor who specializes in medical technology, health, and wellness.