Radiation therapy for chordoma and chondrosarcoma of the skull base and the cervical spine. Prognostic factors and patterns of failure.
BACKGROUND
Prospective analysis of local tumor control, survival and treatment complications in 67 consecutive patients treated with fractionated photon and proton radiation for chordoma or chondrosarcoma of the base of the skull and the cervical spine.


METHODS
Between December 1995 and January 2000, 67 patients with a median age of 52 years (range: 14-85 years), were treated at the Centre de Protonthérapie d'Orsay (CPO), France, using the 201-MeV proton beam, 49 for chordoma and 18 for chondrosarcoma. Irradiation combined high-energy photons and protons. Photons represented two thirds of the total dose and protons one third. The median total dose delivered within gross tumor volume (GTV) was 67 Cobalt Gray Equivalents (CGE; range: 60-70 CGE).


RESULTS
Within a median follow-up of 29 months (range: 4-71 months), the 3-year local control rates were 71% and 85% for chordomas and chondrosarcomas, respectively, and the 3-year overall survival rates 88% and 75%, respectively. 14 tumors (21.5%) failed locally (eight within the GTV, four within the clinical target volume [CTV], and two without further assessment). Seven patients died from their tumor and another one from a nonrelated condition (pulmonary embolism). The maximum tumor diameter and, similarly, the GTV were larger in relapsing patients, compared with the rest of the population: 56 mm vs 44 mm (p = 0.024) and 50 ml vs 22 ml (p = 0.0083), respectively. In univariate analysis, age < or = 52 years at the time of radiotherapy (p = 0.002), maximum diameter < 45 mm (p = 0.02), and GTV < 28 ml (p = 0.02) impacted positively on local control. On multivariate analysis, only age was an independent prognostic factor of local control.


CONCLUSIONS
In chordomas and chondrosarcomas of the skull base and cervical spine, combined photon and proton radiation therapy offers excellent chances of cure. In two thirds of the cases, relapses are located in the GTV. Maximum diameter, GTV, and age are prognostic indicators of local control. These results should be confirmed during a longer follow-up.
Noël
Georges
G
Centre de Protonthérapie d'Orsay, Orsay, France. noel@ipno.in2p3.fr
Habrand
Jean-Louis
JL
Jauffret
Eric
E
de Crevoisier
Renaud
R
Dederke
Sygon
S
Mammar
Hamid
H
Haie-Méder
Christine
C
Pontvert
Dominique
D
Hasboun
Dominique
D
Ferrand
Régis
R
Boisserie
Gilbert
G
Beaudré
Anne
A
Gaboriaud
Geneviève
G
Guedea
Ferran
F
Petriz
Lourdes
L
Mazeron
Jean-Jacques
JJ
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae; D002813:Chondrosarcoma / Q000401:mortality / Q000532:radiotherapy*; D002817:Chordoma / Q000401:mortality / Q000532:radiotherapy*; D003627:Data Interpretation, Statistical; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D017785:Photons / Q000627:therapeutic use; D011379:Prognosis; D011446:Prospective Studies; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D012737:Sex Factors; D019292:Skull Base Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D013125:Spinal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D013997:Time Factors; D011522:Protons
D011522:Protons