3000th ocular tumour patient treated using protons at HZB

A team at Charité - Universitätsmedizin Berlin and the Helmholtz-Zentrum Berlin (HZB) has now treated its 3000^th ocular tumour patient with an individualised proton radiation protocol. This involves irradiating the tumour with fast hydrogen nuclei (protons) that have been accelerated to precisely set energies. These protons penetrate the healthy tissue and only release their energy in the tumour itself.

The tumour is completely destroyed in more than 97 per cent of cases, and vision is at least partly preserved in many of these. “In irradiating small well-defined tumours, proton treatment offers many advantages in comparison to other radiation techniques because it preserves the surrounding tissue. Moreover, thanks to improved surgical procedures following irradiation, we are now able retain some remaining sight even in eyes with very large tumours”, says Prof. Antonia Joussen, Director of the Department of Ophthalmology at Charité. She emphasises in particular the passionate cooperation between ophthalmological specialists, radiation physicists, and radiation therapists as well as with the oncologists who pioneered successful proton treatment for patients.

Particle accelerators for proton treatment

While Charité contributes medical expertise, HZB provides the protons at its Lise-Meitner Campus in Wannsee/Berlin. “Occular tumour treatment offers huge benefit to patients. It is the outstanding collaboration with Charité that provides the basis for this. Together with medical staff, the HZB team has accomplished outstanding work for years in offering ocular tumour treatment using high-quality proton radiation”, says Prof. Anke Kaysser-Pyzalla, Scientific Director of HZB. To accomplish this, the experts at HZB combined two separate particle accelerators for proton treatment – a DC accelerator referred to as a tandetron, as well as a cyclotron in which the protons are accelerated to nearly 40 per cent of the speed of light. “Our accelerator facility delivers precisely the energy we specify according to what the medical physicists want. This high resolution of the energy level facilitates precise control over where tissue is to be destroyed”, explains Dr. Andrea Denker, who heads the Department of Proton Treatment at HZB.

State-of-the-art technology

The facility at HZB treats over 200 patients annually and thus represents one of the largest institutions worldwide, which provides a valuable repository of experience. The facility at HZB also fares extremely well in international comparisons. This has been established in a study by the Particle Therapy Cooperative Oncology Group, for which ten proton-treatment institutions in seven countries were interviewed.

Ever since ocular tumour treatments began, every treatment protocol as well as the post-operative care and follow-ups have been documented in order that predictions of long-term outcomes can be made. The technological level of ocular tumour treatment at HZB is also state-of-the-art: “We were the first to use a digital X-ray system”, explains medical physicist Dr. Jens Heufelder, who continues: “in addition, we not only rely on simple 3D models for creating the irradiation protocols, we use specialised software to integrate the patient’s 3D magnetic resonance and computer tomography data as well. No one else in the world does this.”

The comparative downtime rates are also extremely low: during more than 200 weeks of treatment, it was only necessary to interrupt the operation of the system for more than six hours on two occasions. “The study showed us that we are among the most modern ocular treatment institutions,” says Denker. But she believes measurement of comparative performance is not the actual goal of this study: “We exchange information and experience among ourselves and transmit our experience to others so that patients everywhere receive the best possible treatment.”