Highly conformal therapy using proton component in the management of meningiomas. Preliminary experience of the Centre de Protonthérapie d'Orsay.

AIMS: To evaluate the efficacy and the tolerance of an escalated dose of external conformal fractionated radiation therapy combining photons and protons in the treatment of intracranial meningiomas. PATIENTS AND METHODS: Between December 1995 and December 1999, 17 patients received a treatment by 201-MeV proton beam at the Centre de Protonthérapie d'Orsay (CPO) for a meningioma. Five patients presented a histologically atypical or malignant meningioma, twelve patients a benign one that was recurrent or rapidly progressive. In two cases radiotherapy was administered in the initial course of the disease and in 15 cases at the time of relapse. A highly conformal approach was used combining high-energy photons and protons for approximately 2/3 and 1/3 of the total dose. The median total dose delivered within gross tumor volume was 61 Cobalt Gray Equivalent CGE (25-69). RESULTS: Median follow-up was 37 months (17-60). The 4-year local control and overall survival rates were 87.5 +/- 12% and 88.9 +/- 11%, respectively. One patient failed locally within the clinical tumor volume. One patient died of intercurrent disease. A complete or partial clinical improvement was seen in most of patients. Radiologically, there were eleven stable diseases and five partial responses. In 12/15 recurrent cases, the free interval after radiotherapy is longer than that achieved by the initial surgery. This radiotherapy was well tolerated. CONCLUSIONS: In both benign and more aggressive meningiomas, the combination of conformal photons and protons with a dose escalated by 10-15% offers clinical improvements in most patients as well as radiological long-term stabilization.

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. PATIENTS AND 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. CONCLUSION: 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.