[Requirements and performance profile of the Paediatric Radiation Oncology Working Group (APRO): evaluation of the present situation and description of future developments]. / Anforderungen und Leistungsprofile der Arbeitsgemeinschaft Pädiatrische Radioonkologie (APRO): Eine Bestandsaufnahme und Darstellung zukünftiger Entwicklungen.

BACKGROUND: Radiation therapy is an integral component in the management of childhood malignancies and undergoes a continuous process of optimization within the prospective trials of the GPOH. At present there are approximately 20 active protocols, some specifying radio-oncological study questions, in which about 500 to 600 children annually are given radiotherapy. MATERIALS/METHODS: The Pediatric Radiation Oncology Working Group (APRO) of the German Society for Radiation Oncology (DEGRO) represents the organizational link between GPOH and DEGRO. Their activities range from phrasing guidelines of radio-oncological therapy, through writing a protocol for a prospective study on radiation-induced late effects (RISK--in co-operation with GPOH, 695 patients registered so far) and organizing meetings for information transfer, to implementing radio-oncology within the prospective studies of the GPOH by establishing study chairs for radio-oncology when radio-oncological questions are a primary focus and/or to function as a reference institution for quality assurance. These activities also include individual case consultations outside the study proper. Twice annually the members of the APRO meet for an update on current knowledge and future directions where a representative of the GPOH is invited to contribute special aspects of pediatric oncology. CONCLUSIONS: In the future, modern technology (intensity modulated radiotherapy, proton therapy, inclusion of imaging in treatment planning) will be part of disease management in pediatric oncology. A working group for modern radiotherapy technology was established to enhance this development. Prospective studies of the GPOH with primary or secondary radio-oncological questions require the implementation of corresponding tasks (documentation, monitoring, etc.) in order to meet future demands on clinical trials and to achieve the aims of the protocol. Consequently adequate financial support is indispensable.

[Advances in radio-oncology. From precision radiotherapy with photons to ion therapy with protons and carbon ions]. / Fortschritte in der Radioonkologie. Von der Präzisionsstrahlentherapie mit Photonen zur Ionentherapie mit Protonen und Kohlenstoffionen.

Modern techniques in radiation oncology, such as fractionated stereotactic radiotherapy (FSRT), stereotactic radiosurgery (SRS) or intensity modulated radiotherapy (IMRT) allow the application of high local doses to defined treatment volumes, while normal structures in close vicinity can be spared; high local control rates can be achieved, while treatment-related toxicity can be minimized. Innovative Hi-Art tomotherapy systems offer an alternative, combining a 6 MV photon accelerator with a CT scanner. Ion beams, such as protons and carbon ions, have been shown to be beneficial for distinct tumor entities. Both offer a characteristic physical dose distribution with an inverse dose profile contributing to beneficial dose conformality. Carbon ions also offer the advantage of increased relative biological effectiveness. For certain tumor types, a significant increase in local control and survival rates could be obtained with carbon ions.

Inverse planned stereotactic intensity modulated radiotherapy (IMRT) in the treatment of incompletely and completely resected adenoid cystic carcinomas of the head and neck: initial clinical results and toxicity of treatment.

BACKGROUND: Presenting the initial clinical results in the treatment of complex shaped adenoid cystic carcinomas (ACC) of the head and neck region by inverse planned stereotactic IMRT. MATERIALS: 25 patients with huge ACC in different areas of the head and neck were treated. At the time of radiotherapy two patients already suffered from distant metastases. A complete resection of the tumor was possible in only 4 patients. The remaining patients were incompletely resected (R2: 20; R1: 1). 21 patients received an integrated boost IMRT (IBRT), which allow the use of different single doses for different target volumes in one fraction. All patients were treated after inverse treatment planning and stereotactic target point localization. RESULTS: The mean follow-up was 22.8 months (91-1490 days). According to Kaplan Meier the three year overall survival rate was 72%. 4 patients died caused by a systemic progression of the disease. The three-year recurrence free survival was according to Kaplan Meier in this group of patients 38%. 3 patients developed an in-field recurrence and 3 patient showed a metastasis in an adjacent lymph node of the head and neck region. One patient with an in-field recurrence and a patient with the lymph node recurrence could be re-treated by radiotherapy. Both patients are now controlled. Acute side effects >Grade II did only appear so far in a small number of patients. CONCLUSION: The inverse planned stereotactic IMRT is feasible in the treatment of ACC. By using IMRT, high control rates and low side effects could by achieved. Further evaluation concerning the long term follow-up is needed. Due to the technical advantage of IMRT this treatment modality should be used if a particle therapy is not available.

[Application of (1)H MR spectroscopic imaging in radiation oncology: choline as a marker for determining the relative probability of tumor progression after radiation of glial brain tumors]. / Einsatz der (1)H-MR-spektroskopischen Bildgebung in der Strahlentherapie: Cholin als Marker für die Bestimmung der relativen Wahrscheinlichkeit eines Tumorprogresses nach Bestrahlung glialer Hirntumoren.

PURPOSE: To determine the relative signal intensity ratios of choline (Cho), phosphocreatine (CR) and N-acetyl-aspartate (NAA) in MR spectroscopic imaging (proton-MRSI) for differentiating progressive tumors (PT) from non-progressive tumors (nPT) in follow-up and treatment planning of gliomas. Threshold values to indicate the probability of a progressive tumor were also calculated. MATERIAL AND METHODS: Thirty-four patients with histologically proven gliomas showing a suspicious brain lesion in MRI after stereotactic radiotherapy were evaluated on a 1.5 Tesla unit (Magnetom Vision, Siemens, Erlangen, Germany) using 2D proton MRSI (repetition time/echo time = 1500/135 msec, PRESS; voxel size 9 x 9 x 15 mm (3)). A total of 274 spectra were analyzed (92 voxel were localized within the suspicious brain lesion). Relative signal intensities Cho, Cr and NAA were measured and their ability to discern between PT and nPT was assessed using the linear discrimination method, logistic regression, and the cross-validation method. PT and nPT were differentiated between on the basis of clinical course and follow-up by MRI, CT and positron emission tomography. RESULTS: The Cho parameter and the relative signal intensity ratios of Cr and NAA were most effective in differentiating between PT and nPT. The logistic regression method using the parameter ln(Cho/Cr) and ln(Cho/NAA) had the best predictive results in cross-validation. A sensitivity of 93.8 % and specificity of 85.7 % were achieved in the differentiation of PT from nPT by proton-MRSI. CONCLUSION: (1)H-MRSI has a high sensitivity and specificity for differentiating between therapy-related effects and the relapse of irradiated gliomas. This method allows for assessment of the probability of radiotherapy response or failure.

Stereotactically guided fractionated re-irradiation in recurrent glioblastoma multiforme.

PURPOSE: To assess the feasibility, efficacy and toxicity of fractionated stereotactic radiotherapy in the treatment of recurrent glioblastoma multiforme. PATIENTS AND METHODS: From January 1995 to July 2003, 53 patients with histologically proven glioblastoma multiforme were treated at recurrence with fractionated stereotactic radiation therapy. A median dose of 36 Gy using a median fractionation of 5 x 2 Gy/week was applied. RESULTS: Median overall survival was 21 months, and median overall survival from the time point of re-irradiation was 8 months. The median time interval between primary and secondary radiation therapy was 10 months. In this patient population, no variables predicting longer overall survival could be determined. However, neurosurgical resection at relapse was associated with increased survival after re-irradiation (p=0.04), but left progression-free survival unaltered. Treatment was well-tolerated and no severe toxicities developed. CONCLUSION: Stereotactically guided fractionated re-irradiation is a safe and effective treatment modality in selected cases of recurring glioblastoma multiforme. Since this is not a randomized study, further evaluation in larger patient collectives is warranted. Also, based on recent results of radiochemotherapy in the treatment of primary glioblastoma multiforme, concomitant chemotherapy at relapse might be considered in the future.

[Teleradiology: economic research analysis of CT investigations in a small hospital]. / Teleradiologie: Betriebswirtschaftliche Analyse von CT-Untersuchungen eines kleineren Krankenhauses.

PURPOSE: To evaluate, discuss and compare economic aspects of teleradiological applications in CT examinations in a small hospital. Scenario (1): CT examination by an extern institution including transport of a patient. Szenario (2): External consultation of an internal CT examination (teleradiology according to ROV). Scenario (3): Complete in-house radiology department. To evaluate economic aspects of teleradiology service providers. MATERIALS AND METHODS: Costs have been separated into fixed and variable costs in a model. Total costs of 500 CT examinations per year have been calculated for the three scenarios. A break-even analysis has been performed to determine the necessary/minimal number of CTs per year for economical advantages. The number of CT consultations for teleradiology service providers to make profit has been calculated. RESULTS: Scenario (1): This is the most cost-effective scenario for 500 CTs per year, but most time-consuming. Beyond 548 CTs per year using a single slice CT and 965 CTs per year using a multislice CT the teleradiology scenario [scenario (2)] is most cost-effective. Beyond 1065 CTs per year an in-house radiology department [scenario (3)] is economically reasonable. On the basis of 30 Euros per CT consultation a teleradiology service providing system will be profitable starting from 322 CT consultations per year. CONCLUSION: Teleradiology applications are economically reasonable in a wide range in small hospitals. CT teleradiology services can also be provided on a cost-effective basis at a reachable number of consultations.

Recurrent low-grade gliomas: the role of fractionated stereotactic re-irradiation.

PURPOSE: To assess the effectiveness of re-irradiation in recurrent low-grade gliomas (LGG). PATIENTS AND METHODS: Sixty-three patients were treated with fractionated stereotactic re-irradiation in the case of recurrent gliomas. At primary diagnosis of the tumor, the histology was grade II astrocytoma, oligodendroglioma or oligoastrocytoma. Fifty-two (82.5%) recurrences were in-field, three (4.8%) were localized at the field border, and eight (12.7%) tumors were localized completely out-field of the former RT field, respectively. Using three to four irregular non-coplanar fields formed with a multi-leaf-collimator, we applied a median total dose of 36 Gy (range 15-62 Gy)with a weekly fractionation of 5 x 2 Gy/week depending on the size and the location of the lesion. No concomitant chemotherapy was applied. RESULTS: Radiation was well tolerated by all patients. No severe side effects occurred. Median overall survival was 111 months (range 12-240 months). Extent of neurosurgical resection significantly influenced overall survival (P = 0.02). Median interval between the first radiation therapy and re-irradiation was 50 months (range 5-204 months). From the time point of re-irradiation, median survival was 23 months. Median progression-free survival from the time point of re-irradiation was 12 months (range 2-63 months). No prognosticators could be identified for survival from re-irradiation and progression free survival. CONCLUSION: Our retrospective data suggest that stereotactically guided fractionated re-irradiation in recurrent glioma represents an effective treatment option with good results and few complications. However, further investigation is warranted to consolidate these results and to combine radiation with chemotherapy in the case of recurrent LGG.

Treatment planning for carbon ion radiotherapy in Germany: review of clinical trials and treatment planning studies.

The GSI carbon ion radiotherapy facility established the first completely active beam shaping system for heavy ions, using energy variation on the synchrotron and pencil beam scanning. The introduction of an active beam shaping system for carbon ions has considerable impact on the design of the treatment planning system (TPS). The TPS has to account for the capability of the beam delivery and the biological modelling, which is needed to calculate the RBE for the resulting varying depth dose modulation. The TPS used in clinical routine with carbon ions is described and its use in treatment planning studies are outlined. A clinical trial with carbon ion therapy as primary therapy for chordoma and chondrosarcoma of the base of skull has been completed in 2001. Currently, carbon ion therapy as a boost treatment together with conventional conformal photon therapy or IMRT is under investigation in clinical trials for adenoid cystic carcinoma, chordoma and chondrosarcoma of the cervical spine and sacrococcygeal chordoma. Treatment planning studies comparing carbon ion therapy with IMRT, using optimization of combination therapy, and optimization of beam-line design have already been completed. Analysis of uncertainties in treatment planning has been started with the investigation of range uncertainties stemming from CT imaging. Uncertainties coming from the beam delivery play only a minor role. An attempt to asses the uncertainties introduced in treatment plans by the biological modelling, was done, using phantom verification of calculated cell survival levels. The clinical trials and planning studies are of special importance for the upcoming new clinical ion facility of the Heidelberg university hospital.

The Heidelberg Ion Therapy Center.

The ion beam therapy facility presently under construction at the Department of Clinical Radiology, University of Heidelberg, Germany, will be the first dedicated and hospital-based irradiation facility for protons and heavier ions in Europe. A capacity of more than 1000 patient treatments per year is planned. The facility comprises two horizontally-fixed beamlines for patient treatments plus a fixed-beam experimental area. In addition, the world-wide first scanning ion gantry is under construction. The facility fully relies on an active beam delivery method, the intensity-controlled rasterscan technique. The availability of different ion species ranging from protons to oxygen under identical conditions optimally supports clinical trials aiming to clarify the question of which particle species is best suited for the individual indications. A linac-synchrotron combination will deliver libraries of energy-, focus- and intensity-variable pencil-beams for each ion species to the dose-delivering scanning systems at each treatment station. The available energies correspond to water-equivalent ranges from 2 cm to 30 cm. The intensity-controlled rasterscan technique allows for the administration of inversely planned and biologically optimized dose distributions having utmost precision. The facility will be equipped with state-of-the-art imaging modalities as well as an in-situ Positron-Emission-Tomography (PET). The commissioning of the different sections is scheduled for 2006. The pre-clinical operation will start early in 2007 followed by the routine patient treatment.

Heavy ion therapy: status and perspectives.

Starting with the pioneering work at the University of California in Berkeley in 1977, heavy ion radiotherapy has been of increasing interest especially in Japan and Europe in the last decade. There are currently 3 facilities treating patients with carbon ions, two of them in Japan within a clinical setting. In Germany, a research therapy facility is in operation and the construction of a new hospital based facility at the Heidelberg university will be started soon. An outline of the current status of heavy ion radiotherapy is given with emphasis to the technical aspects of the respective facilities. This includes a description of passive and active beam shaping systems, as well as their implications for treatment planning and dosimetry. The clinical trials and routine treatments performed at the German heavy ion facility are summarized. An overview over the upcoming new facilities and their technical possibilities is given. It is discussed what the necessary improvements are to fully exploit the potential of these facilities. Especially the new Heidelberg facility with the possibility of active beam scanning in combination with the first isocentric gantry for ions and offering beams of protons, helium, oxygen and carbon ions has implications on treatment planning, dosimetry and quality assurance. The necessary and ongoing developments in these areas are summarized. The new facilities also offer the possibilities to perform more extensive clinical studies and to explore future indications for radiotherapy with heavy ions. An overview over the indications and treatment schemes is also given.

Treatment planning intercomparison for spinal chordomas using intensity-modulated photon radiation therapy (IMRT) and carbon ions.

Spinal chordomas cannot be treated with an effective dose using conventional radiation therapy (RT) without exceeding the tolerance dose of the spinal cord while ensuring sufficient target coverage at the same time. In this study we investigate the potential physical advantages of combined photon intensity-modulated radiation therapy (IMRT) and raster-scanned carbon ion RT over photon IMRT alone. For a representative patient we generated a carbon ion RT plan and a photon IMRT plan. Additionally, combined plans consisting of both carbon ions and photon IMRT were calculated using ratios of 20:40 GyE, 30:30 GyE and 40:20 GyE. The best target coverage was obtained using carbon ions alone. Using a combination of photon IMRT and carbon ions, the target coverage was better than with photon IMRT alone. Due to the applied dose constraints, the sparing of the spinal cord was comparable for all plans. Using carbon ions alone, the non-target tissue volume irradiated to at least 30 GyE/50.4 GyE was reduced by 72%/84% compared to photon IMRT alone. These advantages were evident even with combined techniques. The actually delivered dose distribution is expected to be more dependent on patient misalignment with carbon ions compared with photon IMRT. A combination of carbon ions and photon IMRT might be preferable in order to profit by the physical advantages of carbon ions while ensuring a safe treatment.

[Modern techniques in the radiotherapy of prostate cancer. Non-surgical treatment options for localized stages]. / Moderne Techniken in der Radiotherapie des Prostatakarzinoms. Nichtoperative Optionen bei lokalisierten Stadien.

The implementation of computer-assisted three-dimensional radiotherapy treatment planning methods based on computed tomography together with sophisticated beam modeling with individual blocks and multi-leaf-collimators in the 90's enabled the creation of steep dose gradients between the target volume and surrounding radiosensitive normal tissue. For prostate cancer, a clear dose dependence between the treated radiation dose and the treatment success is proven, especially for patients with intermediate and unfavorable prognostic criteria. However, with conventional radiotherapy, rectum and urinary bladder are limiting the applicable dose. New technical methods allow a safe dose escalation without increasing of treatment-related toxicity. An improvement in terms of PSA remission and local control was yielded. This article presents the different established external beam and interstitial treatment techniques and their clinical results.

Centroblastic-centrocytic non-Hodgkin's lymphoma stage I-III: patterns of failure following radiotherapy.

AIM: To investigate the patterns of failure and survival after involved-field or more extensive radiotherapy for centroblastic-centrocytic non-Hodgkin's lymphoma (NHL) as well as the impact of radiotherapy dose on local control. PATIENTS AND METHODS: 47 patients with Stage I-III centroblastic-centrocytic NHL were treated with involved-field (IF) extended-field radiotherapy (EF-RT) or total lymphatic irradiation (TLI). The involved regions received 25.5-50 Gy, non-involved regions were treated with a dose of 26 Gy in most cases. RESULTS: In Stage I/II, the majority of relapses (64%) were nodal and were located adjacent or distant to the former radiation portals. 79% of relapses occurred after IF-RT, 21% after EF-RT or TLI. 5-year overall survival (OAS) after EF-RT/TLI and IF-RT for Stages I/II was 85% and 83%, respectively (n.s.); relapse free survival (RFS) was 73% and 61%, respectively (n.s.). A tendency for better overall survival was found for patients who relapsed at one or two sites (5-year overall survival 100%) compared to patients with three or more relapse sites (5-year overall survival 0%). For Stage III overall survival was 72%, freedom from progression (FFP) was 27% at 5 years. We found a dose-effect correlation for local control with a relapse rate of 31% after 26-34 Gy and 4% after application of 36 Gy; no relapses occurred after doses of 40 Gy or more. CONCLUSION: In involved lymph node regions a relatively small number of relapses was observed after application of a minimal dose of 36 Gy. In Stages I/II most relapses were located outside the radiation portals, yet EF-RT was not superior to IF-RT in terms of overall survival and relapse free survival. Prospective randomized trials are necessary to prove a potentially favorable effect of more extended radiotherapy portals (TLI or TNI [total nodal irradiation]) and to evaluate the optimal radiotherapy dose.

Fractionated stereotactic conformal radiation therapy of brain stem gliomas: outcome and prognostic factors.

BACKGROUND AND PURPOSE: Evaluation of outcome and prognostic factors in patients with brain stem glioma (BSG) following fractionated stereotactic radiotherapy (FSRT). MATERIALS AND METHODS: Between 1990 and 1997, we treated 41 patients with FSRT in a phase I/II trial. Median age was 24 years. Out of 36 patients with histologically proven glioma, ten had a partial tumour resection. Histology revealed low grade gliomas in 30 patients and anaplastic gliomas in six patients. A mean total dose of 54 Gy was given in daily fractions of 1.8 Gy. Median follow-up was 12 months. RESULTS: Three patients died during FSRT. Neurological improvement was achieved in 19/38 patients. Reduction of tumour size was reported in 12/38, in 16 patients the lesion was unchanged, ten showed progression. Median time to progression was 23 months, median overall survival 40 months with an actuarial survival of 83% at 1 year, 55% at 3 years and 33% at 5 years. In 20 of 22 patients with recurrence progression was inside the target volume. Significant prognostic factors for survival were clinical and radiological response 6 weeks after FSRT. Treatment toxicity was mild. Ototoxicity occurred in one patient. CONCLUSIONS: FSRT is a feasible treatment modality for BSG with tolerable toxicity. The risk of marginal failure is low.

[Carbon ion irradiation of skull base tumors at GSI. First clinical results and future perspectives]. / Bestrahlung von Schädelbasistumoren mit Kohlenstoffionen bei der GSI. Erste klinische Ergebnisse und zukünftige Perspektiven.

BACKGROUND: Radiobiological and physical examinations suggest clinical advantages of heavy ion irradiation. We report the results of 23 women and 22 men (median age 48 years) with skull base tumors irradiated with carbon ion beams at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt, from December 1997 until September 1999. PATIENTS AND METHODS: The study included patients with chordomas (17), chondrosarcomas (10) and other skull base tumors (Table 1). It is the first time that the intensity-controlled rasterscan-technique and the application of positron-emission tomography (PET) for quality assurance was used. All patients had computed tomography for three-dimensional-treatment planning (Figure 1). Patients with chordomas and chondrosarcomas underwent fractionated carbon ion irradiation in 20 consecutive days (median total dose 60 GyE). Other histologies were treated with a carbon ion boost of 15 to 18 GyE delivered to the macroscopic tumor after fractionated stereotactic radiotherapy (median total dose 63 GyE). RESULTS: Mean follow-up was 9 months. Irradiation was well tolerated by all patients. Partial tumor remission was seen in 7 patients (15.5%) (Figure 2). One-year local control rate was 94%. One patient (2.2%) deceased. No severe toxicity and no local recurrence within the treated volume were observed. CONCLUSION: Clinical effectiveness and technical feasibility of this therapy modality could clearly be demonstrated in our study. To evaluate the clinical relevance of the different beam modalities studies with larger patient numbers are necessary. To continue our project a new heavy ion accelerator exclusively for clinical use is planned to be constructed in Heidelberg.

[First experiences with a noninvasive patient set-up system for radiotherapy of the prostate]. / Erste Erfahrungen mit einem nichtinvasiven Patientenfixierungssystem für die stereotaktische Strahlentherapie der Prostata.

PURPOSE: Highly conformal radiotherapy techniques require precise patient positioning. We report our first experience with a new cast system for fixation of the pelvis during stereotactically guided intensity modulated radiotherapy (IMRT) of the prostate with respect to positioning accuracy of the prostate. MATERIAL AND METHODS: The immobilization device consists of a custom-made wrap-around body cast that extends from the abdomen to the thighs and a separate head mask, both made from Scotchcast, and attaches to a frame for extracranial stereotaxy. Sixteen CT-studies (> or = 25 slices, thickness: 3 mm) of 2 patients who were immobilized for IMRT of prostate tumors were evaluated with respect to set-up accuracy of bony structures and the prostate itself. CT-studies were performed immediately before or after a treatment fraction. Deviations of bony landmarks and anatomical landmarks inside the planning target volume were measured in all 3 dimensions. RESULTS: Mean patient movements of 0.15 +/- 0.3 mm (latero-lateral), 0.9 +/- 1 mm (anterior-posterior), 1 +/- 1 mm (tranversal vectorial error) and < 3 mm slice thickness (craniocaudal) were recorded using bony landmarks and 0.9 +/- 0.9 mm (latero-lateral), 1.8 +/- 1.5 mm (anterior-posterior), 2.2 +/- 1.5 mm (transversal vectorial error) and < 3 mm (craniocaudal) using the confines of, or landmarks within the prostate. Standard deviations of absolute positioning error as an often used metric for positioning accuracy ranged between 0.3 and 1.7 mm in the transversal plane. The worst case transversal vectorial deviation for the prostate was 4.4 mm. Figure 4 summarizes the set-up accuracy of bony landmarks and the prostate. CONCLUSION: The presented combination of a body cast and head mask system in a rigid stereotactic body frame ensures reliable noninvasive patient fixation for fractionated extracranial stereotactic radiotherapy. It provides precise and reliable positioning of the prostate and meets the requirements for highly conformal radiotherapy such as IMRT. No further improvement of repositioning can be achieved with external immobilization devices since the positioning error of the target relative to the skeleton exceeds the accuracy of the positioning of the skeleton itself.

Stereotactic fractionated radiotherapy for chordomas and chondrosarcomas of the skull base.

PURPOSE: To investigate the treatment outcome of patients suffering from skull base chordoma or chondrosarcoma after fractionated stereotactic radiotherapy. METHODS AND MATERIALS: We report 45 patients treated for chordoma or chondrosarcoma with postoperative fractionated stereotactic radiotherapy between 1990 and 1997. Patients had CT and MRI for 3D treatment planning performed under stereotactic guidance. Median dose at isocenter was 66.6 Gy for chordomas and 64.9 Gy for chondrosarcomas. MRI imaging was obtained in intervals after therapy to evaluate local relapse. Survival was calculated according to the Kaplan-Meier method. RESULTS: All chondrosarcomas had achieved and maintained local control and recurrence-free status at follow-up of 5 years. Local control rate of chordomas was 82% at 2 years and 50% at 5 years. Survival was 97% at 2 years and 82% at 5 years. At maximum follow-up of 8 years local control and survival rate of chordomas was 40% (82%). Clinically significant late toxicity developed in one patient. CONCLUSIONS: Our results demonstrate the feasibility of fractionated photon beam therapy and its success in the treatment of skull base tumors. Modern 3D treatment techniques provide superior results compared to conventional techniques. The role of high-precision radiotherapy compared to particle beam therapy in the treatment of these tumors is not yet fully clear and further research is needed.