Long-Term Outcomes of High-Dose Single-Fraction Radiosurgery for Chordomas of the Spine and Sacrum

Abstract

INTRODUCTION To evaluate outcomes of patients with primary chordomas treated with spine stereotactic radiosurgery (SRS) alone or in combination with surgery, drawing from a single-institution database to elucidate treatment options associated with durable radiographic control of these conventionally radioresistant tumors. Chordomas result in significant morbidity, with a high rate of local recurrence and potential for metastases. SRS as a primary treatment could save patients from extensive surgery. Spine SRS outcomes support exploration of its role in the durable control of these conventionally radioresistant tumors. METHODS Clinical records were reviewed for outcomes of patients with primary chordoma of the mobile spine and sacrum who underwent single-fraction SRS between 2006 and 2017. Radiographic local recurrence-free survival (LRFS), overall survival (OS), symptom response, and toxicity were assessed in relation to extent of surgery. RESULTS In total, 35 patients with de novo chordoma of the mobile spine (49%) and sacrum (51%) received SRS with a median post-SRS follow-up of 38.8 mo (range: 2.0-122.9). The median PTV dose was 24Gy (range: 18–24Gy). Overall, 12 patients (33%) underwent definitive SRS and 23 patients (66%) underwent surgery followed by adjuvant SRS. Surgical strategies included separation surgery prior to SRS, curettage/intralesional resection, and en bloc resection in 7, 6, and 10 patients, respectively. The 3- and 5-yr LRFS rates were 86.2% and 80.5% respectively. Among 32 patients receiving 24 Gy (91%), the 3- and 5-yr LRFS were 96.3% and 89.9%. The 3- and 5-yr OS rates were 90.0% and 84.3%. The symptom response rate to treatment was 88% for pain and radiculopathy. Extent or type of surgery was not associated with LRFS, OS, or symptom response rates (P > .05), but en bloc resection was associated with higher CTCAE v. 5.0 surgical toxicity compared to epidural decompression and curettage/intralesional resection (P = .03). The long-term = grade 2 SRS toxicity rate was 31%, including 17% grade 3 tissue necrosis, recurrent laryngeal nerve palsy, fracture, and secondary malignancy. CONCLUSION High-dose spine SRS offers the chance of durable radiographic control and effective symptom relief with acceptable toxicity for primary chordomas as either definitive or adjuvant therapy.

Feasibility of achieving planned surgical margins in primary spine tumor: a PTRON study

“…The best available evidence supports margin-appropriate en bloc surgery to decrease local recurrence and improve survival. 2,3,[22][23][24][25][26][27][28] However, this is not always possible given the proximity to vital structures, such as the spinal cord, nerves, and vasculature. 2,26,29 Given their proximity to vital structures, between 35% and 65% of sacral chor- domas and approximately 21% of mobile spine chordomas are amenable to en bloc resection with negative surgical margins.…”

“…2,3,[22][23][24][25][26][27][28] However, this is not always possible given the proximity to vital structures, such as the spinal cord, nerves, and vasculature. 2,26,29 Given their proximity to vital structures, between 35% and 65% of sacral chor- domas and approximately 21% of mobile spine chordomas are amenable to en bloc resection with negative surgical margins. 14,[30][31][32][33] Even when resection is feasible, microscopic satellite spread outside the planned resection site or failure to achieve surgical margins may lead to increased recurrence.…”

“…14,[30][31][32][33] Even when resection is feasible, microscopic satellite spread outside the planned resection site or failure to achieve surgical margins may lead to increased recurrence. 2 This has pushed some groups to rely more heavily on neoadjuvant and adjuvant treatment and to try to limit the surgical footprint. Nevertheless, even when neoadjuvant and adjuvant therapies are used, the addition of en bloc resection seems to confer an advantage in local control.…”

“…1 Resection according to Enneking principles has been associated with the best chance of achieving local control or even a cure. [2][3][4][5] En bloc resection aims to remove a tumor in a single piece encased by healthy tissue. 6,7 However, without a description of the pathologic margin, "en bloc resection" can be misleading because it refers to only an attempt to remove the tumor in one piece.…”

Recent advances in understanding and managing chordomas: an update

“…Despite aggressive surgical treatment and adjuvant radiotherapy, recurrence rates remain upward of 50%, with many of these cases occurring late, sometimes more than 5 years after the initial intervention 35 – 38 , although some more recent stereotactic radiosurgery protocols managed to achieve a 5-year local recurrence-free survival upward of 80% 39 . These timeframes make prolonged surveillance necessary, even in cases where gross total resection was achieved.…”