Phase II study of high-dose photon/proton radiotherapy in the management of spine sarcomas.
OBJECTIVE
Radiotherapy (XRT) for spine sarcomas is constrained by spinal cord, nerve, and viscera tolerance. Negative surgical margins are uncommon; hence, doses of >or=66 Gy are recommended. A Phase II clinical trial evaluated high-dose photon/proton XRT for spine sarcomas.


METHODS
Eligible patients had nonmetastatic, thoracic, lumbar, and/or sacral spine/paraspinal sarcomas. Treatment included pre- and/or postoperative photon/proton XRT with or without radical resection; patients with osteosarcoma and Ewing's sarcoma received chemotherapy. Shrinking fields delivered 50.4 cobalt Gray equivalent (Gy RBE) to subclinical disease, 70.2 Gy RBE to microscopic disease in the tumor bed, and 77.4 Gy RBE to gross disease at 1.8 Gy RBE qd. Doses were reduced for radiosensitive histologies, concurrent chemoradiation, or when diabetes or autoimmune disease present. Spinal cord dose was limited to 63/54 Gy RBE to surface/center. Intraoperative boost doses of 7.5 to 10 Gy could be given by dural plaque.


RESULTS
A total of 50 patients (29 chordoma, 14 chondrosarcoma, 7 other) underwent gross total (n = 25) or subtotal (n = 12) resection or biopsy (n = 13). With 48 month median follow-up, 5-year actuarial local control, recurrence-free survival, and overall survival are: 78%, 63%, and 87% respectively. Two of 36 (5.6%) patients treated for primary versus 7/14 (50%) for recurrent tumor developed local recurrence (p < 0.001). Five patients developed late radiation-associated complications; no myelopathy developed but three sacral neuropathies appeared after 77.12 to 77.4 Gy RBE.


CONCLUSIONS
Local control with this treatment is high in patients radiated at the time of primary presentation. Spinal cord dose constraints appear to be safe. Sacral nerves receiving 77.12-77.4 Gy RBE are at risk for late toxicity.
DeLaney
Thomas F
TF
Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. tdelaney@partners.org
Liebsch
Norbert J
NJ
Pedlow
Francis X
FX
Adams
Judith
J
Dean
Susan
S
Yeap
Beow Y
BY
McManus
Patricia
P
Rosenberg
Andrew E
AE
Nielsen
G Petur
GP
Harmon
David C
DC
Spiro
Ira J
IJ
Raskin
Kevin A
KA
Suit
Herman D
HD
Yoon
Sam S
SS
Hornicek
Francis J
FJ
D006801:Humans; D018365:Neoplasm, Residual; D012516:Osteosarcoma / Q000188:drug therapy / Q000532:radiotherapy / Q000601:surgery; D017785:Photons / Q000627:therapeutic use*; D011446:Prospective Studies; D061766:Proton Therapy; D011836:Radiation Tolerance; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D012062:Relative Biological Effectiveness; D012509:Sarcoma / Q000532:radiotherapy* / Q000601:surgery; D012512:Sarcoma, Ewing / Q000188:drug therapy / Q000532:radiotherapy / Q000601:surgery; D013116:Spinal Cord / Q000528:radiation effects; D013125:Spinal Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D011522:Protons
D011522:Protons