Intramedullary spinal cord metastases treated with CyberKnife radiosurgery: Robert E. Lieberson, MD, John R. Adler, MD, Scott G. Soltys, MD, Iris C. Gibbs, MD and Steven D. Chang, MD ten cases, a brief review of the literature, and treatment recommendations
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Intramedullary spinal cord metastases treated with CyberKnife
radiosurgery:
Robert E. Lieberson, MD, John R. Adler, MD,Scott G. Soltys, MD, Iris C. Gibbs, MD and
Steven D. Chang, MD
ten cases, a brief review of the literature, and treatment recommendations
Presentation of SCIM’s• Of all patients with cancer:
– 33% get vertebral body mets– 4% get leptomeningeal mets– only 0.1 to 0.4% get
intramedullary mets• Primaries similar to brain
– Lung, breast, melanoma, renal
CyberKnife Radiosurgery• Well established for bony,
epidural, and extramedullary mets
• Well established for intramedullary AVMs and hemangioblastomas
• Used for ependymomas• Only case reports and
one mixed series on SCIM’s
SCIM Patient Characteristics
• With in cord substance including pial based• Age 39 to 77 years (median 66, SD 14.6)• 7 women, 3 men (10 patients)• 7/11 cervical, 4/11 thoracic (11 tumors)• All CTCAE grade ≥ 3
Clinical• 5 breast, 2 NSC lung, 1 prostate,
1 teratoma, 1 hemangioepithelioma• All had numerous other lesions,
– 5/10 with brain mets– 6/10 with vertebral body mets
• 2 with 1, 2 with 3, and 2 with TNTC– 3/10 with intradural mets, 1/10 carcinomatosis
8 w/ multiple bleeds• Symptoms improved in > 50%• No hemorrhage after SRS• No mortality• 3 patients had increased
symptoms (10%)• 1 radiation myelopathy
(3%)
Other IM Lesions• Ependymomas
– 3 tumors in 2 pts reported in 2003 (now 5/4)
– Mean 18 Gy, 1 or 2 sessions– All smaller, no complications
• Hemangioblastomas– 16 spinal in 12 pts reported in
2003 (now 31/19)– Mean 21.3 Gy, 1 to 4 sessions– 15/16 stable or smaller,
no complications– Cysts poorly treated
Spinal Cord Dose
• Other published “guidelines” for cord dose– Chang, et al, and others Vmax less than ~ 10 – 14 Gy– Ryu, et al, 10% under 10 Gy (cord contoured 6 mm
above and below lesion)– Gibbs, et al, V8 ≤ 1 cc
• Daly, et al, in IM hemangioblastomas the cord receives the full marginal dose– Single fraction Dmax as high as 22.4 Gy – All
“guidelines” exceeded– No radiation toxicity – true limit unknown–
Hemangioblastomas / Daly, et al, IJROBP 80:213 (2011)
Conclusions• Largest series of SCIMs treated with CyberKnife• Our patients had multiple other metastases,
overall survival was poor, but …– Treatment preserved function– There were no local recurrences– There was no radiation toxicity – Fewer sessions than conventional radiation– Less morbidity than open surgery
• SRS a good option for intramedullary spinal cord metastases.