Interview with Professor Jürgen Debus, MD, PhD
Medical Director of the Department of Radiation Oncology and Radiation Therapy of Heidelberg University Hospital
Science-Medical Director of HIT
November 2nd, 2009, was the opening ceremony for the Heidelberg Ion-Beam Therapy Center, or HIT, after six years of construction. Is this the start of a new era in oncology radiotherapy in Heidelberg?
Prof. Debus: The HIT is definitely one of the greatest medical research projects ever implemented in Germany. Heidelberg University Hospital is proud to operate a unique radiotherapy center equipped with state-of-the-art technology. With the HIT, we are embarking on a uniquely innovative, very promising journey in radiation oncology. Ion beam radiation will help many cancer patients. The clinical studies we are planning for the next few years will show us which tumors can be treated most successfully using different kinds of modern radiotherapy. They will help us identify which patients profit most from which specific treatment alternative – protons, heavy ions, or conventional photons. This information is very important in order to tailor radiotherapy even more to each tumor patient and thus improve the chances of a cure. With HIT, we will be able to set new international treatment standards.
I would like to mention that this project was implemented successfully because four prestigious partner institutes have been involved since the planning stage: the Department of Radiation Oncology at Heidelberg University Hospital, the GSI Helmholtzzentrum for Heavy Ion Research in Darmstadt, the German Cancer Research Center in Heidelberg, and the Forschungszentrum Dresden-Rossendorf. Moreover, HIT was implemented as a cooperation project between the Department of Radiation Oncology at Heidelberg University Hospital and Siemens AG Deutschland, which was responsible for the installation of the radiation units.
The first cancer patients will begin radiation before the end of the year. Many pin great hopes on this treatment. But how many can actually be helped by radiation at HIT?
Prof. Debus: We assume that about five to ten percent of all cancer patients will benefit from radiation therapy with protons or heavy ions. This amounts to approx. 10,000 patients per year. When HIT has reached maximum capacity in two years, 1,300 patients can be treated here annually. This includes patients who do not respond, or respond only poorly, to conventional photon therapy – x-rays or gamma rays – or whose tumor continues to grow despite radiation. Often, tumors that are located deep inside the body or are surrounded by healthy tissue extremely sensitive to radiation, such as the eyes, optic nerve, brain stem, or bowel. In these cases, it is simply not possible using conventional radiation methods to administer a dose of radiation sufficient to destroy the tumor but at the same time spare the adjacent tissue. HIT intends to close this treatment gap with its state-of-the-art technology and very effective proton and heavy ion radiation.
What tumor patients are treated at HIT?
Prof. Debus: We will start by treating patients suffering from chordomas and chondrosarcomas of the skull base – these are tumors that arise in the bone and cartilage tissue of this area – and patients with large adenoid cystic salivary gland carcinomas. In our clinical studies at the GSI Helmholtzzentrum for Heavy Ion Research, over 400 patients with these tumors were successfully radiated with heavy ions from 1997 to 2008 and many of them were cured. These excellent study results laid the foundations for the HIT. Those tumors are today considered an absolute indication for therapy with heavy ions. We are pleased that the experience with heavy ion therapy we acquired over many years will now benefit patients at HIT.
What clinical studies with patients are planned at HIT?
Prof. Debus: HIT is the first therapy center in Europe to offer radiation with protons and with heavy ions. This makes comparative clinical studies possible. We are planning several clinical studies for the next few years in which we want to examine what other tumors that have thus far been difficult to treat by radiation can be treated more effectively with protons or heavy ions and possibly even cured. These studies are being prepared very carefully and will be initiated gradually in the coming years. The Department of Radiation Oncology at Heidelberg University Hospital and the German Society for Radiation Oncology (DEGRO) worked jointly with the health insurers to compile a list of tumors for which clinical studies at HIT are planned. This list can be seen on our website. It includes certain prostate, lung, and liver tumors, and tumors in children.
Why do children benefit especially from therapy at HIT?
Prof. Debus: For children it is especially important to avoid long-term side effects of therapy. Since ion beams make it possible to spare healthy tissue, growth and developmental problems and the development of secondary tumors can be avoided. Among the most frequent tumors in children that will be treated at the HIT in the coming years are brain tumors and soft tissue tumors known as sarcomas.
Heidelberg will be the coordination center for all clinical studies on proton radiation conducted in Germany. What other German centers offer this treatment?
Prof. Debus: In Germany, two other centers in Marburg and in Kiel will be offering combined proton and carbon ion treatment in the next three years. A center in Munich, the Rinecker Proton Therapy Center (RPTC) began radiation treatment with protons in March 2009. The Westdeutsche Protonentherapiezentrum in Essen will follow next year.
Together with the German Cancer Research Center (dkfz) in Heidelberg, the Department of Radiation Oncology at Heidelberg University Hospital will function as a coordination center to coordinate studies and consolidate results. It has been commissioned by the German Society for Radiation Oncology (DEGRO) for this task. HIT will be the only treatment center in the world for some time where treatment with protons and heavy ions can be provided from a gantry.
How is it possible to radiate so precisely with ion beams?
Prof. Debus: Ion beams consist of ions. These are electrically charged particles – protons or heavy ions. This type of radiation has several advantages over conventional radiation with photons. The ion beam penetrates tissue as quickly as an arrow. In contrast to a photon beam, it loses very little energy through scattering to adjacent tissue and gives off all its effective energy at once at the end of its range – which is where the tumor is. This area, where the radiation reaches its peak level, is called the Bragg peak. Beyond the tumor, the dose falls back to almost zero. This means that the normal tissue in front of, adjacent, and behind the tumor is spared as optimally as never before – this is especially important when sensitive organs such as eyes or the bowel are located adjacent to the tumor.
Depending on the location of the tumor in the body, the ion beam can be directed to penetrate up to 30 centimeters into the tissue – thus up to ten times deeper than a photon beam. This is why even tumors located deep inside the body can receive a sufficiently high dose of radiation.
Does ion beam radiation have any other advantages aside from its greater precision?
Prof. Debus: Heavy ions are also more biologically effective. They have greater destructive power than conventional photon radiation. This means that a tumor cell radiated with heavy ions is much more likely to die because its genetic material is irreparably damaged. After photon radiation, the damage to genetic material is often less serious and can be repaired by the tumor cell.
Heavy ions can also destroy tumors that grow very slowly or have poor circulation. Photons can achieve next to nothing with such tumors. In addition, higher doses can be administered with ion beams. Because they are much more precise and spare healthy tissue, the radiation dose can be increased with respect to conventional photon radiation – by up to 20 percent for proton radiation and up to 35 percent for heavy ion radiation. The higher the dose, the greater the probability that a patient will be cured.
The HIT is equipped with state-of-the-art technological innovations. First and foremost of these is the heavy ion gantry. What are the therapy advantages of the gantry?
Prof. Debus: The HIT is the first treatment center in the world with a heavy ion gantry. A gantry is a radiation source that can be rotated 360º. It has been used successfully for conventional radiation therapy for years, allowing us to build on this experience. This technology was first used for heavy ions at HIT.
A gantry allows the therapy beam to be set at an optimal angle. This is helpful for tumors in complicated locations and where very radiation-sensitive tissue lies in the radiation channel. To protect this tissue, the tumor is irradiated from various directions. The gantry rotates around the patient and radiates the preset radiation dose from every position. The individual beams overlap in the tumor area and only here add up to the total radiation dose. Healthy adjacent tissue is exposed only to a fraction of the radiation dose and is not damaged.
The gantry will not be in operation until 2010, as the facility must begin operations gradually. We will first begin with treatment at the two other treatment sites that are equipped with a fixed horizontal beam.
Cancer patients treated at HIT are given a radiation dose that is the most precise and safest in the world. How can that be guaranteed?
Prof. Debus: At HIT we use what is known as an “intensity-modulated raster scanning technique”, a method in which in fact, assures a never before achieved precision in the three-dimensional radiation of tumors. In this method, the beam “scans” points on the tumor and every single point is given the previously calculated target dose. You can imagine the result as follows: custom-designed bundles of beams “envelop” the tumor precisely – similar to how a glove fits the hand. The radiation is correspondingly precise.
In addition, “online therapy control” is implemented at HIT, in which the position and intensity of the beam in the body is checked 10,000 times per second by computer. If there is the slightest deviation the machine switches off within half a millisecond – thus reacting 1,000 times faster than a human. It could not be safer.
How much does treatment at HIT cost? Do the health insurers pay the cost of treatment?
Prof. Debus: Radiation treatment at HIT costs about 20,000 euros, making it three times as expensive as conventional radiation. It is about as expensive as cancer treatment consisting of surgery and chemotherapy.
The Department of Radiation Oncology at Heidelberg University Hospital has signed a contract with the statutory health insurers in Germany in which they agree to assume the costs for radiation with proton and heavy ions for all tumor patients who the German Society for Radiation Oncology (DEGRO) considers will benefit from this therapy. A list can be found on the HIT website.
If we consider the unique technology at HIT and the advantages of ion beam treatment, the question arises as to what significance conventional radiation therapy with photons will have in the future.
Prof. Debus: Conventional radiation therapy with photons will remain an indispensable pillar in oncology therapy, if only for reasons of capacity. After surgery, it is the most successful and most frequently used cancer treatment – and will remain so.
Groundbreaking new developments in medical physics and computer science in recent years led to an enormous increase in quality in radiation therapy with photons and to ever increasing success rates. This was made possible by very high performance imaging methods such as CT and MRI scanning, three-dimensional radiation therapy planning and computer simulation, and by the various radiation techniques available today, from which the most suitable method is individually chosen for every cancer patient.
I would also like to mention that intensity-modulated radiation and a gantry for example, have already been used very successfully in conventional radiation therapy for many years. At HIT they are now being used for ion-beam therapy for the first time.
What methods of conventional radiation therapy are offered at Heidelberg University Hospital?
Prof. Debus: All of them – intraoperative radiation therapy, intensity-modulated radiotherapy, fractionated stereotactic radiotherapy, tomotherapy, and image-guided radiotherapy. When planning radiotherapy, three-dimensional radiotherapy planning and virtual simulation are used.
Heidelberg has the advantage of being able to offer the entire arsenal of modern radiotherapy diagnostics and treatment at one location, because HIT, the university hospital, and neighboring research institutes such as the German Cancer Research Center, the medical faculty of Heidelberg University with its research concentration in oncology, and the National Center for Tumor Diseases in Heidelberg cooperate closely with facilities and staff. The HIT is embedded in a unique clinical and research environment.
Every radiotherapy patient in Heidelberg receives radiation treatment at the highest international standard, no matter which method is used. Very few locations in the world can offer that.
How can patients contact physicians at HIT?
Prof. Debus: Patients can come personally, or contact us through their physician. Our hotline number is +49 6221 56-5445. They can also go to the outpatient clinic of the Department of Radiation Oncology in the Kopfklinik Heidelberg, Im Neuenheimer Feld 400, Tel. +49 6221 56-7611. Or send an email to strahlentherapie(at)med.uni-heidelberg.de. It is important to bring all previous findings and files.