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.