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.

[Treatment of nasopharyngeal cancer: literature review].

The conventional radiotherapy and the associated treatments improved the prognostic of nasopharyngeal cancer. A better selection of the patients who must have a more aggressive treatment also probably contributed to this improvement. Even if a relation could be found between the locoregional relapse rate and the distant relapse rate, these two events remain often independent.

Combination of photon and proton radiation therapy for chordomas and chondrosarcomas of the skull base: the Centre de Protonthérapie D'Orsay experience.

Purpose: Prospective analysis of local tumor control, survival, and treatment complications in 44 consecutive patients treated with fractionated photon and proton radiation for a chordoma or chondrosarcoma of the skull base.

Methods And Materials: Between December 1995 and December 1998, 45 patients with a median age of 55 years (14-85) were treated using a 201-MeV proton beam at the Centre de Protonthérapie d'Orsay, 34 for a chordoma and 11 for a chondrosarcoma. Irradiation combined high-energy photons and protons.

[Role of radiotherapy in the treatment of cerebral meningiomas].

Cerebral meningiomas account for 15-20% of all cerebral tumours. Although seldom malignant, they frequently recur in spite of complete surgery, which remains the cornerstone of the treatment. In order to decrease the probability of local recurrence, radiotherapy has often been recommended in atypical or malignant meningioma as well as in benign meningioma which was incompletely resected.

[Postmastectomy locoregional radiotherapy for breast cancer: literature review].

Postoperative radiotherapy is controversial after radical mastectomy. Recent clinical trials have shown an increase in survival with this irradiation and conclusions of previous meta-analyses should be reconsidered. The results of a large number of randomized clinical trials in which women received post-mastectomy radiotherapy or not have been reviewed.

[Radiotherapy using a combination of photons and protons for locally aggressive intracranial tumors. Preliminary results of protocol CPO 94-C1].

Purpose: From October 1993 through July 1998, 48 assessable adult patients with non-resectable aggressive intracranial tumors were treated by a combination of high dose photon + proton therapy at the Centre de Protonthérapie d'Orsay.

Patients And Methods: Grade 1 and 4 gliomas were excluded. Patients benefited from a 3D dose calculation based on high-definition CT and MRI, a stereotactic positioning using implanted fiducial markers and a thermoplastic mask.

Proton beam therapy (PT) in the management of CNS tumors in childhood.

At the Centre de Protontherapie d'Orsay, nine children with intra-cranial malignancies were treated between July 1994 and January 1998. Immediate and late tolerances were excellent in all cases (follow-up 2 to 50 months). Two patients recurred locally (marginal failures), seven are alive and doing well.

A preliminary comparative treatment planning study for radiotherapy of age-related maculopathy.

Purpose: We present a comparative planning of different approaches for external radiotherapy in age-related maculopathies.

Materials And Methods: Calculated dose distributions and dose-volume histograms for (a) bilateral irradiation with 6 MV photons, (b) a single lateral-oblique beam using either photons, electrons or protons and (c) an anterior circular proton beam.

Results: For lateral photon or electron beams the dose to the lens is usually lower than 10% of the dose to the macula.

A model for the lateral penumbra in water of a 200-MeV proton beam devoted to clinical applications.

An experimental approach for modeling the lateral penumbra of a proton beam has been investigated. Measurements were made with a silicon diode in a water tank. Several geometrical configurations (phantom position, collimator-to-surface distance, collimator diameter, bolus thickness, air gap, etc.

Proton dosimetry comparison involving ionometry and calorimetry.

A comparison of the absorbed dose to tissue determined by various ionization chambers, Faraday cups, and an A-150 plastic calorimeter was performed in the 200 MeV proton beam of Orsay, France. Four European proton-therapy centers (Clatterbridge, UK, Louvain la Neuve, Belgium, and Nice and Orsay, France) participated in the comparison. An agreement of better than 1% was observed in the absorbed dose to A-150 measured with the different chambers of the participating groups.

[Initial results of proton therapy in choroidal melanoma at the d'Orsey Center for Proton Therapy; the first 464 cases].

Purpose: Retrospective analysis of the treatment of choroidal melanoma with protontherapy at the Centre de protonthérapie d'Orsay, France.

Patients And Methods: Between September 1991 and September 1995, 612 patients presenting with choroidal melanoma were treated by protontherapy in Orsay. Following initial management of the first 464 patients, results were analyzed, as were results after a 1-year follow-up for 305 patients, a 2-year follow-up for 169 patients, and a 3-year follow-up for 59 patients.

Clinical applications of proton therapy.

Proton therapy offers considerable potential advantages in the management of poorly resectable, radio-resistent tumors close to critical anatomical structures. So far over 15,000 patients have been treated worldwide with two major indications: conservative management of ocular melanomas in which local control exceeds 95% at 5 years and curative irradiation of sarcomas at the base of the skull and cervical canal, with a survival rate between 84 and 94% at 5 years. The different protocols tested currently worldwide are discussed.

Quality assurance in protontherapy: a systematic approach in progress at Orsay.

The degree of accuracy and reliability required in proton therapy can only be guaranteed if a comprehensive quality assurance (QA) programme is established. Such a programme obviously has common features with general QA in radiotherapy, but some aspects are specific to the use of protons and particularly to the characteristics of each facility. A study is in progress at Orsay to convert a series of quality controls into a systematic quality assurance programme.

An experimental approach to the design of a scattering system for a proton therapy beam line dedicated to ophthalmological applications.

Purpose: The development of a scattering system for a proton therapy beam line dedicated to ophthalmological applications.

Methods And Materials: A protontherapy beam line has been developed for the treatment of uveal melanoma at the Orsay synchrocyclotron. The original 200 MeV proton beam is degraded to 76 MeV and the final beam characteristics (range, modulation, flatness, collimation) are obtained with beam modifiers in the treatment room.

Clinical applications of proton therapy. Experiences and ongoing studies.

Proton therapy offers potentially considerable advantages in the management of slow-growing, poorly resectable or non-resectable tumors resistant to x-rays and located close to critical radiosensitive anatomical structures, such as the brain stem of the spinal cord. Among over 13,000 irradiated patients in the USA, Europe, and Japan, two major clinical indications have been documented: 1. The conservative management of choroidal melanomas, in which 98% 5-year local control can be expected at the price of low toxicity and visual preservation in approximately half of them.