Giant Cell Tumor of Lumbar Spine Treated with RapidArc Intensity Modulated Arc Therapy: Case Report and Review of Literature

Abstract

Background: Giant cell tumors of the lumbar spine are rare and complete resection without major functional comprise is challenging despite advancements in spine surgery techniques. Radiation therapy has been an option in such cases; however there are high concerns for associated high small bowel toxicity and lack of dose escalation to achieve local control. With advent of intensity modulated radiation therapy (IMRT) it is now possible to give high radiation dose to tumor with minimal toxicity. Herein we present a rare case of giant cell tumor of fourth lumbar (L4) vertebra treated with RapidArc intensity modulated arc therapy (IMAT) with relevant review of literature. Methods: A 30-year-old female had low back pain for 6 months. She underwent surgical decompression at another hospital as having a L4-5 protruded intervertebral disc 2 months previously, but her back pain progressed with weakness of both legs with restricted movement. Radiological and pathological work-up confirmed the diagnosis of giant cell tumor of L4 vertebra. She refused further surgery and was referred to us for radiotherapy. Treatment plans for prescribed radiation dose of 59.4 Gy in 30 fractions were made by 3DCRT and RapidArc IMAT and comparison was made. Student’s unpaired t test was used to determine the significance of the difference between two plans in terms of dose to the tumor and small bowel. A p value of 0.05 was considered statistically significant. Related literature was searched. Results: In RapidArc IMAT and 3DCRT plans mean doses to planning treatment volume (PTV) were 61.24 Gy (55.98 - 66.23) and 60.71 Gy (49.87 - 63.74) respectively (p 0.04) and mean doses to small bowel were found lesser in RapidArc plan [14.78 Gy (range: 0.39 - 53.15)] as compared to 3DCRT plan. Patient was started on RapidArc IMRT and she completed the course without any major sequelae. Conclusion: Lumbar spine giant cell tumors are rare and complete resection is often not possible. RapidArc IMAT is a feasible option for such patients to deliver high dose radiation to achieve good local control with marked symptom relief and without severe toxicity.