Proton therapy of uveal melanomas in Berlin. 5 years of experience at the Hahn-Meitner Institute.

BACKGROUND AND PURPOSE: In June 1998, proton-beam therapy of ocular tumors started at the Hahn-Meitner Institute Berlin, Germany. The purpose of the present study is to evaluate treatment outcome for uveal melanomas. PATIENTS AND METHODS: 245 consecutive patients with primary melanoma of the uvea were treated from June 1998 to April 2003 with a 68-MeV proton beam. In 96.2% of all patients, a uniform fractionation scheme was applied: single dose 15 CGE (cobalt gray equivalent), total dose 60 CGE on 4 consecutive days. Follow-up is available in 229 patients. RESULTS: At the time of median follow-up (18.4 months), local control is 96.4% and 95.5% at 3 years. Eye retention rate is 92.6% at 20 months (median follow-up) and 87.5% at 3 years. CONCLUSION: Proton-beam irradiation of uveal melanomas at the Hahn-Meitner Institute after the first 5 years of its initiation reveals local tumor control and eye retention rates in the range of other centers with larger experience. Delivering high treatment quality in hadron therapy from the beginning has been achieved.

[BANG-polymer dosimetry in the proton therapy of eye neoplasms]. / BANG-Polymergeldosimetrie in der Protonentherapie von Augentumoren.

The use of polymer gel makes it possible to measure three-dimensional dose distributions of ionizing radiation. Phantoms with BANG-1 and BANG-3 gel were irradiated using a 68 MeV proton beam at the eye tumour therapy beam line of the Hahn Meitner Institute in Berlin. Up to twelve treatment fields could be applied to one gel phantom. The investigations consisted of mono-energetic Bragg curves, spread-out Bragg curves of circular fields (diameter 20 mm), and spread-out Bragg curves of patient fields. Magnetic resonance imaging was used to obtain the gel dose distributions. The results were compared to measurements of a water-phantom ionization chamber. The BANG polymer gels showed a significant quenching of Bragg peaks compared to ionization chamber measurements. The BANG-3 gel was found to be unsuitable for further investigations with 68 MeV protons. The use of BANG-1 allowed the verification of wedge slopes and irregular field forms. On the basis of our experience, polymer gels are well suited for quality assurance in proton therapy in principle.

[Five years of proton therapy of eye neoplasms at the Hahn-Meitner Institute, Berlin]. / Fünf Jahre Protonentherapie von Augentumoren am Hahn-Meitner-Institut Berlin.

Eye tumors (choroidal melanomas, iris melanomas, and choroidal hemangiomas) are being treated with 68 MeV protons since 1998 at the Ion Beam Laboratory of the Hahn-Meitner Institute of Berlin (Germany's first proton therapy center), in cooperation with the Charité University Hospital in Berlin, Campus Benjamin Franklin. The proton beam, generated via a combination of Van de Graaff accelerator and cyclotron, is prepared by passive shaping for conformal tumor irradiation. A digital X-ray verification of the tumor location with the patient in sitting position limits the position uncertainties to a maximum of 0.3 mm. The treatment planning is performed using the program EYEPLAN. OCTOPUS, a CT-based planning program developed in cooperation with the German Cancer Research Center of Heidelberg, is under pre-clinical testing. Thus far, more than 400 patients have been irradiated. The first results are comparable to those obtained in other proton therapy centers. At the end of 2002, the University Hospital of Essen has also become a cooperation partner of the Hahn-Meitner Institute.