10.12.2009 | Ion Beam Cancer Therapy – Low Risk of Late Effects
The new ion beam cancer therapy has a much lower risk of late effects than regular radio therapy. Researchers at the GSI Helmholtzzentrum für Schwerionenforschung were now able to prove the significantly low probability of late effects with their experiments. Their blood tests on patients with prostate tumors confirmed the prior risk estimation. A high cure rate and minimal late effects are the core advantages of ion beam cancer therapy. Over ten years ago, the first of 440 patients received ion treatment at the GSI Helmholtzzentrum, where tumors at the base of skull, spinal marrow and prostate were treated. A few weeks ago, the first public ion beam treatment facility, the Heidelberg Ion Therapy Center, took up routine operation.
"The fact that ion radiation shows a very low probability for late effects in prostate tumors suggests that this is also true for other types of tumors. This is an additional convincing argument for using of the ion beam therapy. To be able to benefit from these remarkable features, the GSI Helmholtzzentrum developed and implemented an entirely new irradiation process", says Professor Marco Durante, head of the biophysics department at GSI.
"We tested the blood cells of prostate cancer patients for damage on the chromosomes. The number of damages on the chromosomes was lower in patients who received ion beam treatment than in the patients who were treated with conventional radiation methods. Chromosome damage is an indicator for the probability of late effects, such as the development of secondary tumors", says Sylvia Ritter, project head at GSI’s biophysics department.
In any type of radiation treatment, the radiation beam affects healthy tissue while traveling through the body to reach the tumors cells. While the intensely damaging effect on the tumor tissue is absolutely intended, harm to the surrounding healthy tissue should be kept to a minimum. Compared to X-ray treatment, irradiation with ion beams provides a high radiation dose in the tumor while the surrounding healthy tissue receives a much lower radiation load.
Experts at GSI already predicted that the late effects of ion beam therapy are much lower than those of the well-established radiation treatments. Now, so-called molecular cytogenetic assays confirmed their prediction. Only one comparable study on secondary damages from ion-beam therapy was conducted in Japan in the year 2000. Testing patients with uterine or esophagus tumors, this study also determined a low probability of late effects from ion beam therapy.
GSI researchers tested blood samples from 20 prostate cancer patients who received a combination of ion and X-ray treatment or X-ray radiation only. For their tests, the GSI experts used white blood cells. As part of the blood, the white blood cells travel through the entire body, which makes them particularly suitable for determining damage to the chromosomes caused by radiation therapy and for predicting the probability of late effects.
To determine the increase in chromosome damage caused by radiation therapy, the patients’ blood samples were taken before, during and after the treatment. The blood samples were then compared to those of healthy patients. Chromosomes carry our genetic information and are located in the cell nucleus of every single human cell. To render the chromosomes visible, the scientists applied a method called mFISH (multicolor fluorescent in situ hybridization). The mFISH method is used to stain the genetic material in different colors and to depict the chromosomes as a so-called karyogram. This color coding allows the scientists to determine damages caused by radiation in a very safe and quick way.
Scientists from GSI and the Department of Radiology at the Heidelberg University Hospital participated in this research. The study was supported by the Federal Ministry of Education and Research (BMBF) under the contracts no. 02S8203 and no. 02S8497.
About Ion Beam Tumor Therapy
Since 1997, the novel treatment developed at the GSI Helmholtzzentrum für Schwerionenforschung has been used for patients with head and neck tumors. In 2006, the treatment was extended to include patients with prostate tumors. Ion beam therapy is a very precise, yet gentle therapy method. Ion beams penetrate the body and only exert their full impact deep within the tissue, in a spot the size of a pinhead. The ion beams are steered with precision so exact that a tumor the size of a tennis ball can be irradiated point by point with millimeter accuracy. The ion beam treatment is particularly suited for deep-seated tumors that are close to vital or important organs, like the brain stem, the optic nerve, the bladder or the intestine.
As the new treatment form showed very good results, the Radiology Department of Heidelberg University Hospital opened a special Ion Therapy Center in November 2009. A yearly number of 1,300 patients can be treated at the Heidelberg Ion Therapy Center (HIT). Two more facilities are under construction in Marburg and Kiel, Germany.
About the GSI Helmholtzzentrum für Schwerionenforschung
GSI is a research Center of the Helmholtz-Gemeinschaft in Darmstadt, Germany. It is financed by the German federation and the German state of Hesse with a budget of 90 million euros. GSI’s research goal is to create a comprehensive picture of our surrounding nature. In this spirit, GSI’s over 1,000 employees operate a one-of-a-kind accelerator facility for ion beams. More than 1,000 guest scientists from all over the world use the accelerator facility for their fundamental research. GSI’s research program comprises a broad range of fields from nuclear and atom physics to plasma and materials research to biophysics.
GSI’s most prominent advancements are the discovery of new chemical elements and the development of a novel cancer therapy using ion beams. With these cutting-edge innovations and many more scientific novelties, GSI is a global leader in ion beam research. With the construction of the new international accelerator facility FAIR (Facility for Antiproton and Ion Research) at GSI, the center will be able to continue its world-class research. The new FAIR facility will give researchers the opportunity to conduct a variety of experiments, with which they hope to gain new insights into the structure of matter and the evolution of the universe.