- Email: [email protected]
28 Invited Prescribing, recording, reporting in endovascular brachytherapy
Symposia
significantly reduces the complexity, effort, time, expense and/or resources required, and 3) is generic enough to be suitable (or easily adapted) to a broad range of patients. IMRT represents a powerful new tool in the radiotherapeutic armamentarium. Because of the high incidence and prevalence of breast cancer in women, even small relative gains in survival and recurrence free outcomes will translate to large absolute gains. IMRT is potentially an effective method of minimizing the risk of recurrence, cause-specific death, and fatal complications,
ENDOVASCULAR BRACHYTHERAPY 28 Invited P r e s c r i b i n g , recording, reporting in endovascular brachytherapy R. P6tter Department of Radiotherapy and Radiobiology, University of Vienna, Austria A common language is mandatory for the communication in endovascular brachytherapy which applies for the whole procedure of prescribing, recording and reporting. A common language is also necessary for scientific evaluation and comparison of results among different institutions. A variety of medical specialists, co-operating during endovascular brachytherapy have different tasks and responsibilities, dependent on their specific background, training and practice. A systematic description is given about the principles which should be taken into account in the multidisciplinary treatment procedure (EVA GEC ESTRO Recommendations. PStter et al. Radiother OncoL 2001; 59: 339-360). Indication for EVBT is agreed upon in a joint protocol. The determination of Lesion Length (LL) and the vessel Reference Lumen Diameter (RLDi) is up to the interventionalist, who performs the angioplasty and also introduces and positions the radiation delivery catheter. The Interventional Length (IL) is determined by the interventionalist in cooperation with the radiation oncologist. The Clinical and Planning Target Length (CTL, PTL) is defined by the radiation oncotogist in cooperation with the interventionalist and the radiation physicist taking standard or individual safety margins proximal and distal to the IL. Treatment planning is performed by the radiation physicist, radiation oncologist or radiation technologist. The Reference lsodose Length (RIL) is determined by the radiation physicist and is fixed to a certain Active Source Length (ASL) and approved by both the radiation oncologist and the interventionalist. Dose prescription is performed by the radiation oncologist and the interventionatist according to a joint protocol, tn a retrospective analysis recently finished by the Vienna Endovascular Brachytherapy Working Group (Schmid et al. Radiother Onco12002; 63 (S): 12 the quality of EVBT was evaluated using the concept and terminology of the EVA GEC ESTRO Recommendations and correlated to outcome. Assessment of geographical miss (GM) was done by comparing the interventions (IL) with the RIL of the sources used, based on CD recorded angiograms. Evaluation was done on 128 patients. GM was defined as injured segment of the vessel, which received a lower dose than 90% of the reference dose. In case of no GM the safety margin (IL plus x) was mean 8.0mm at proximal edges and 7.5ram at distal edges. 95% of all GM were observed within total margins (proximal + distal margin) lower than 10.5mm. The restenosis rate was 7.5% compared to 27.8% in the injured vessel with insufficient dose. Conclusion: GM in endocoronary brachytherapy can be avoided by adding at least an overall 10mm safety margin to the IL. The restenosis rate then is expected to be below 10% which is the gold standard for interventions in stenotic arteries. With such results endovascular brachytherapy will be able to compete with the new drug eluting stents. 29
Invited
Intravascular Brachytherapy: Clinical results- State of the art B. Pokraiac Univ. Klinik for Strahlentherapie und Strahlenbiologie, Wien, Austria Percutaneous transluminal angioplasty of coronary and femoropopliteal arteries is well accepted, successful therapeutic modality for the treatment of arterial stenosis and occlusions. Major limitation of angioplasty is the renarrowing or restenosis of the artery. Endovascular brachytherapy following immediately after angioplasty has shown in many experimental studies a very strong potential to reduce neointimal proliferation which is concerned to be a major cause of vessel restenosis after balloon dilatation. Clinical trials using both 13 (strontium-90, phosporus-32) and gamma (iridium-192) sources have been conducted in past four years. These studies in coronar-
Wednesday, 18 September 2002 $9
ies have confirmed a significant reduction of restenosis rate. Beta trials (START, INHIBIT, Dose Finding Study) and gamma trials (SCRIPPS, GAMMA-I, GAMMA-2) have been equally successful. Positive results obtained in these investigations have lead to the FDA approval of endovascular brachytherapy for the treatment of coronary in-stent restenosis. The role of radiotherapy in the treatment of de-novo lesions is the subject of intensive investigations. The efficacy of brachytherapy for the treatment of diabetic patients, patients with renal failure, small vessels and multiple lesions is also investigated. VIENNA trials and PARIS feasibility study have shown significant reduction of restenosis after femoropopliteal PTA. Endovascular brachytherapy is a multidisciplinary work between cardiologists, angiotogists, radiation oncologist and medical physicists. To improve the already successful collaboration between different specialties recommendations for this treatment were done by AAPM, DGMP and EVA GEC ESTRO. The brachytherapy for prevention against restenosis after angloplasty in femoropopliteal and coronary arteries has been proven to be feasible, safe and effective. However, many questions are still open such as the use of centering devices, adequate safety margins, long term side effects. Carefully designed and performed follow-up studies through many years are necessary to determine the tong term therapeutic benefit including possible adverse side effects. The studies with antipreliferative coated stents are ongoing in coronary and peripheral arteries. The question is if the very low restenosis rate obtained in coronaries could be achieved also in the femoropopliteal artery. Depending on the results of these trials definitive role of brachytherapy in the restenosis prophylaxis will be established in the future. 30 Invited D r u g e l u U n g stents I. De Scheerder, Y. Huang, Z. Hui, E. Verbeken, E. Schacht University Hospitals, Leuven, Belgium Although coronary stenting can reduce the rate of angiographic restenosis and improve the clinical outcome in some lesion subsets, it is still hampered by early (sub)acute thrombosis and late restenosis. Material-induced (sub)acute thrombotic events are kept under clinical control since the introduction of potent antiplatelet drugs. So the major remaining problem after coronary stenting remains the increased neointimal hyperplasia and in-stent restenosis. Systematically administered pharmacological agents evaluated to reduce neointimal hyperplasia have failed, most probably because of the low active drug concentrations at the target site. Local drug delivery catheters are hampered by the short drug application time and the potential increased vessel injury caused by the drug injection. Endovascular stents may be the ideal platform for local drug delivery, since they can serve as a reservoir for local drug administration. Synthetic or biological polymers can be used as matrices for drug incorporation and elution. Concerns about polymer biocompatibility and sterility however drove investigators to look for other solutions. To eliminate potential inflammatory polymers, direct binding of drug to the metal backbone was introduced. This method is however hampered by the limited amount of drug that can be loaded and the too fast release of the drug after stent implantation. To overcome these problems, alterations to the stent backbone were suggested. Surface modification (pores, micropores, pits, perforations.... ) allowing greater amounts of drug to be directly coated to the stent metallic backbone are now under development. These surface modifications furthermore results in a slower drug release to the target lesion.
RADIATION DAMAGE TO THE BOWEL 31
Invited
Endothelial apoptosis as primary lesion initiating radiation d a m a g e in mice F. Paris 1, H.-J. Ch'ang2, Z. Fuks 3, R. Kolesnick4 l lnserm, U463, Nantes, France 2National Health Research Institut, Cancer Research, Taipei, Taiwan 3Memorial SloanKettering Cancer Center, Radiation Oncology, New York, USA 4Memorial Sloan-Kettering Cancer Center, Laboratory of Signal Transduction, New York, USA Damage to the gastrointestinal (GI) tract by chemotherapy or radiation limits their efficacy in the treatment of cancer. It is generally accepted, although
significantly reduces the complexity, effort, time, expense and/or resources required, and 3) is generic enough to be suitable (or easily adapted) to a broad range of patients. IMRT represents a powerful new tool in the radiotherapeutic armamentarium. Because of the high incidence and prevalence of breast cancer in women, even small relative gains in survival and recurrence free outcomes will translate to large absolute gains. IMRT is potentially an effective method of minimizing the risk of recurrence, cause-specific death, and fatal complications,
ENDOVASCULAR BRACHYTHERAPY 28 Invited P r e s c r i b i n g , recording, reporting in endovascular brachytherapy R. P6tter Department of Radiotherapy and Radiobiology, University of Vienna, Austria A common language is mandatory for the communication in endovascular brachytherapy which applies for the whole procedure of prescribing, recording and reporting. A common language is also necessary for scientific evaluation and comparison of results among different institutions. A variety of medical specialists, co-operating during endovascular brachytherapy have different tasks and responsibilities, dependent on their specific background, training and practice. A systematic description is given about the principles which should be taken into account in the multidisciplinary treatment procedure (EVA GEC ESTRO Recommendations. PStter et al. Radiother OncoL 2001; 59: 339-360). Indication for EVBT is agreed upon in a joint protocol. The determination of Lesion Length (LL) and the vessel Reference Lumen Diameter (RLDi) is up to the interventionalist, who performs the angioplasty and also introduces and positions the radiation delivery catheter. The Interventional Length (IL) is determined by the interventionalist in cooperation with the radiation oncologist. The Clinical and Planning Target Length (CTL, PTL) is defined by the radiation oncotogist in cooperation with the interventionalist and the radiation physicist taking standard or individual safety margins proximal and distal to the IL. Treatment planning is performed by the radiation physicist, radiation oncologist or radiation technologist. The Reference lsodose Length (RIL) is determined by the radiation physicist and is fixed to a certain Active Source Length (ASL) and approved by both the radiation oncologist and the interventionalist. Dose prescription is performed by the radiation oncologist and the interventionatist according to a joint protocol, tn a retrospective analysis recently finished by the Vienna Endovascular Brachytherapy Working Group (Schmid et al. Radiother Onco12002; 63 (S): 12 the quality of EVBT was evaluated using the concept and terminology of the EVA GEC ESTRO Recommendations and correlated to outcome. Assessment of geographical miss (GM) was done by comparing the interventions (IL) with the RIL of the sources used, based on CD recorded angiograms. Evaluation was done on 128 patients. GM was defined as injured segment of the vessel, which received a lower dose than 90% of the reference dose. In case of no GM the safety margin (IL plus x) was mean 8.0mm at proximal edges and 7.5ram at distal edges. 95% of all GM were observed within total margins (proximal + distal margin) lower than 10.5mm. The restenosis rate was 7.5% compared to 27.8% in the injured vessel with insufficient dose. Conclusion: GM in endocoronary brachytherapy can be avoided by adding at least an overall 10mm safety margin to the IL. The restenosis rate then is expected to be below 10% which is the gold standard for interventions in stenotic arteries. With such results endovascular brachytherapy will be able to compete with the new drug eluting stents. 29
Invited
Intravascular Brachytherapy: Clinical results- State of the art B. Pokraiac Univ. Klinik for Strahlentherapie und Strahlenbiologie, Wien, Austria Percutaneous transluminal angioplasty of coronary and femoropopliteal arteries is well accepted, successful therapeutic modality for the treatment of arterial stenosis and occlusions. Major limitation of angioplasty is the renarrowing or restenosis of the artery. Endovascular brachytherapy following immediately after angioplasty has shown in many experimental studies a very strong potential to reduce neointimal proliferation which is concerned to be a major cause of vessel restenosis after balloon dilatation. Clinical trials using both 13 (strontium-90, phosporus-32) and gamma (iridium-192) sources have been conducted in past four years. These studies in coronar-
Wednesday, 18 September 2002 $9
ies have confirmed a significant reduction of restenosis rate. Beta trials (START, INHIBIT, Dose Finding Study) and gamma trials (SCRIPPS, GAMMA-I, GAMMA-2) have been equally successful. Positive results obtained in these investigations have lead to the FDA approval of endovascular brachytherapy for the treatment of coronary in-stent restenosis. The role of radiotherapy in the treatment of de-novo lesions is the subject of intensive investigations. The efficacy of brachytherapy for the treatment of diabetic patients, patients with renal failure, small vessels and multiple lesions is also investigated. VIENNA trials and PARIS feasibility study have shown significant reduction of restenosis after femoropopliteal PTA. Endovascular brachytherapy is a multidisciplinary work between cardiologists, angiotogists, radiation oncologist and medical physicists. To improve the already successful collaboration between different specialties recommendations for this treatment were done by AAPM, DGMP and EVA GEC ESTRO. The brachytherapy for prevention against restenosis after angloplasty in femoropopliteal and coronary arteries has been proven to be feasible, safe and effective. However, many questions are still open such as the use of centering devices, adequate safety margins, long term side effects. Carefully designed and performed follow-up studies through many years are necessary to determine the tong term therapeutic benefit including possible adverse side effects. The studies with antipreliferative coated stents are ongoing in coronary and peripheral arteries. The question is if the very low restenosis rate obtained in coronaries could be achieved also in the femoropopliteal artery. Depending on the results of these trials definitive role of brachytherapy in the restenosis prophylaxis will be established in the future. 30 Invited D r u g e l u U n g stents I. De Scheerder, Y. Huang, Z. Hui, E. Verbeken, E. Schacht University Hospitals, Leuven, Belgium Although coronary stenting can reduce the rate of angiographic restenosis and improve the clinical outcome in some lesion subsets, it is still hampered by early (sub)acute thrombosis and late restenosis. Material-induced (sub)acute thrombotic events are kept under clinical control since the introduction of potent antiplatelet drugs. So the major remaining problem after coronary stenting remains the increased neointimal hyperplasia and in-stent restenosis. Systematically administered pharmacological agents evaluated to reduce neointimal hyperplasia have failed, most probably because of the low active drug concentrations at the target site. Local drug delivery catheters are hampered by the short drug application time and the potential increased vessel injury caused by the drug injection. Endovascular stents may be the ideal platform for local drug delivery, since they can serve as a reservoir for local drug administration. Synthetic or biological polymers can be used as matrices for drug incorporation and elution. Concerns about polymer biocompatibility and sterility however drove investigators to look for other solutions. To eliminate potential inflammatory polymers, direct binding of drug to the metal backbone was introduced. This method is however hampered by the limited amount of drug that can be loaded and the too fast release of the drug after stent implantation. To overcome these problems, alterations to the stent backbone were suggested. Surface modification (pores, micropores, pits, perforations.... ) allowing greater amounts of drug to be directly coated to the stent metallic backbone are now under development. These surface modifications furthermore results in a slower drug release to the target lesion.
RADIATION DAMAGE TO THE BOWEL 31
Invited
Endothelial apoptosis as primary lesion initiating radiation d a m a g e in mice F. Paris 1, H.-J. Ch'ang2, Z. Fuks 3, R. Kolesnick4 l lnserm, U463, Nantes, France 2National Health Research Institut, Cancer Research, Taipei, Taiwan 3Memorial SloanKettering Cancer Center, Radiation Oncology, New York, USA 4Memorial Sloan-Kettering Cancer Center, Laboratory of Signal Transduction, New York, USA Damage to the gastrointestinal (GI) tract by chemotherapy or radiation limits their efficacy in the treatment of cancer. It is generally accepted, although