2153 - Promising Outcomes of Stereotactic Radiotherapy for Rare Extracranial Schwannomas: A Single-Institution Analysis of Pain and Local Stability

03:00pm - 04:00pm ET

Poster Hall - Exhibit Hall A

Screen: 1

POSTER

Presenter(s)

Anna Misiorowska-Golosz, MD - Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice, Slaskie

A. Misiorowska-Golosz¹, A. Roch-Zniszczol¹, I. Debosz-Suwinska¹, J. Wydmanski², B. Goc¹, D. Gräupner¹, A. J. Namysl-Kaletka¹, and S. Blamek²; ¹Department of Radiotherapy, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice, Poland, ²Department of Radiotherapy, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch., Gliwice, Poland

Purpose/Objective(s):

Extracranial schwannomas (ES) are rare benign peripheral nerve sheath tumors that may cause significant pain and neurological symptoms. Surgical resection is the standard of care but is challenging because of the risk of postoperative neurological deficits. This study evaluated the clinical efficacy, radiological response, and safety of stereotactic radiotherapy (SRT) for ES.

Materials/Methods:

We retrospectively analyzed medical records of 22 patients with ES treated with SRT between 2010 and 2025. The primary endpoints were pain response and local tumor control, evaluated in the follow-up imaging performed mainly using magnetic resonance imaging (MRI). Radiotherapy was delivered using a robotic stereotactic radiotherapy system in 19 cases and a conventional linear accelerator in 3 cases. The fractionation schedules included 3×6 Gy, 2×8 Gy, 5×5 Gy, and 3×8 Gy. Two patients underwent a prior surgical intervention.

Results:

The median age at treatment was 55 years (range 28–83), with equal gender distribution. Tumor locations by spinal segment included cervical spine (35%), thoracic spine (22%), lumbar spine (26%), sacral spine (13%), and cervicothoracic junction (4%).

Pain was the most common presenting symptom (18), followed by numbness (5), and four patients were asymptomatic. The location of the tumor was intracanal in 5 patients, intraforaminal in 2, extracanal in 2, and mixed in the remaining cases. Spinal cord compression on MRI was present in 5 patients (23%). The median follow-up was 39.5 months.

The mean volume of the treated tumor was 5.82 cm³ (range 0.2–16.6 cm³). The maximum spinal cord dose ranged from 0 to 24.48 Gy, the mean spinal cord dose from 0 to 12.42 Gy. The volume of the spinal cord that received 50% of the prescribed dose ranged from 0 to 1.13 cm³, and the dose to 1 cm³ of the spinal cord ranged from 0 to 10.73 Gy.

At first imaging follow-up, approximately one year after treatment, 15 patients showed stable disease, 2 had partial regression, and 1 had progression. Four patients had <12 months of follow-up and one patient had 12 months of follow-up. SRT was highly effective in pain management. After one year, 13 patients experienced pain improvement or total resolution. Only one patient experienced progression during follow-up. No acute or late radiation-related toxicities were observed.

Conclusion:

The study concludes that SRT is an effective and safe treatment for extracranial schwannomas. It provides durable local tumor control and long-term pain relief with no observed treatment-related complications. These results support SRT as a valuable noninvasive alternative for patients who are poor surgical candidates or require symptom control.