V. Budach

HIGH-DOSE RATE INTERSTITIAL WITH EXTERNAL BEAM IRRADIATION FOR LOCALIZED PROSTATE CANCER : RESULTS OF A PROSPECTIVE TRIAL

PURPOSE A prospective phase II trial was carried out to test the feasibility and effectiveness of a combined interstitial with external beam radiotherapy approach for localized prostate cancer. MATERIALS AND METHODS Between October 1992 and December 1994, 82 evaluable patients were treated. T2 and T3 tumours, according to the AJCC classification system of 1992, were found in 21 and 61 cases, respectively. The median follow-up was 24 months; three patients were lost during follow-up. All of the patients were pathologically proven to be node-negative by laparoscopic node dissection of the fossa obturatoria region. A dose of 9 Gy a week was prescribed during the first and second weeks of treatment (10 Gy each week from October 1992 to December 1993) interstitially with high-dose rate Iridium-192 brachytherapy to the prostate and tumour extension beyond the capsule. External beam four-field box irradiation was then given to the prostate to a dose of 45 Gy/25 fractions (40 Gy/20 fractions from October 1992 to December 1993). RESULTS Before starting treatment, a PSA value of > or =10 ng/ml was found in 64.6% (53/82) of patients with a median PSA of 14.0 ng/ml. The median PSA 3, 12 and 24 months after completion of therapy was 1.20, 0.78 and 0.70 ng/ml, respectively. The PSA value was < 1.0 ng/ ml in 52.9% of patients at 2 years. Negative punch biopsies 12 and 24 months after therapy were observed in 69.8% (44/63) and 73. 1% (38/ 52) of patients, respectively. A positive biopsy combined with a PSA value of > 1.0 ng/ml was considered as local failure. The local tumour control rate was 79.5% at 2 years. Acute side-effects were not increased relative to external beam irradiation alone. Severe side-effects were observed in three patients (two of the three patients had additional risk factors (colitis ulcerosa and diabetes mellitus)); they developed rectourethral fistulae requiring colostomy after biopsies from the anterior rectal wall. CONCLUSION The described method is feasible and well tolerable. The three complications observed were not caused by irradiation alone. Biopsies from the anterior rectal wall after definitive high-dose radiotherapy for prostate cancer have to be seen as obsolete. The rate of negative prostate biopsies of 73.1% after 24 months represents an encouraging result.

Preoperative radiochemotherapy in locally advanced or recurrent rectal cancer: regional radiofrequency hyperthermia correlates with clinical parameters

PURPOSE Preoperative radiochemotherapy (RCT) is a widely used means of treatment for patients suffering from primary, locally advanced, or recurrent rectal cancer. We evaluated the efficacy of treatment due to additional application of regional hyperthermia (HRCT) to this conventional therapy regime in a Phase II study, employing the annular phased-array system BSD-2000 (SIGMA-60 applicator). The clinical results of the trial were encouraging. We investigated the relationship between a variety of thermal and clinical parameters in order to assess the adequacy of thermometry, the effectiveness of hyperthermia therapy, and its potential contribution to clinical endpoints. METHODS AND MATERIALS A preoperative combination of radiotherapy (1.8 Gy for 5 days a week, total dose 45 Gy applied over 5 weeks) and chemotherapy (low-dose 5-fluorouracil [5-FU] plus leucovorin in the first and fourth week) was administered to 37 patients with primary rectal cancer (PRC) and 18 patients with recurrent rectal cancer (RRC). Regional hyperthermia (RHT) was applied once a week prior to the daily irradiation fraction of 1.8 Gy. Temperatures were registered along rectal catheters using Bowman thermistors. Measurement points related to the tumor were specified after estimating the section of the catheter in near contact with the tumor. Three patients with local recurrence after abdominoperineal resection, had their catheters positioned transgluteally under CT guidance, where the section of the catheter related to the tumor was estimated from the CT scans. Index temperatures (especially T(max), T(90)) averaged over time, cumulative minutes (cum min) (here for T(90) > reference temperature 40.5 degrees C), and equivalent minutes (equ min) (with respect to 43 degrees C) were derived from repetitive temperature-position scans (5- to 10-min intervals) utilizing software specially developed for this purpose on a PC platform. Using the statistical software package SPSS a careful analysis was performed, not only of the variance of thermal parameters with respect to clinical criteria such as toxicity, response, and survival but also its dependency on tumor characteristics. RESULTS The rate of resectability (89%) and response (59%) were high for the PRC group, and a clear positive correlation existed between index temperatures (T(90)) and thermal doses (cum min T(90) >/= 40.5 degrees C). Even though the overall 5-year survival was encouraging (60%) and significantly associated with response, there was no statistically significant relationship between temperature parameters and long-term survival for this limited number of patients. However, nonresectable tumors with higher thermal parameters (especially cum min T(90) >/= 40.5 degrees C) had a tendency for better overall survival. We found even higher temperatures in patients with recurrences (T(90) = 40.7 degrees C versus T(90) = 40.2 degrees C). However, these conditions for easier heating did not involve a favorable clinical outcome, since surgical resectability (22%) and response rate (28%) for the RRC group were low. We did not notice any other dependency of thermal parameters to a specific tumor or patient characteristics. Finally, neither acute toxicity (hot spots) induced by hyperthermia or RCT nor perioperative morbidity were correlated with temperature-derived parameters. Only a higher probability for the occurrence of hot spots was found during treatment with elevated power levels. CONCLUSION In this study with two subgroups, i.e., patients with PRC (n = 37) and RRC (n = 18), there exists a positive interrelationship between thermal parameters (such as T(90), cum min T(90) >/= 40,5 degrees C) and clinical parameters concerning effectiveness. Additional hyperthermia treatment does not seem to enhance toxicity or subacute morbidity. Procedures to measure temperatures and to derive thermal parameters, as well as the hyperthermia technique itself appear adequate enough to classify heat treatments in

High Dose Rate Brachytherapy of Localized Prostate Cancer

Abstract Objective: We evaluated the safety and efficacy of high dose rate (HDR) brachytherapy using Iridium-192 (Ir 192) and 3D conformal external beam radiotherapy in patients with localized prostate cancer. Methods: A total of 444 patients with localized prostate cancer underwent combined radiotherapy with interstitial Ir 192 and 3D conformal external beam radiotherapy between December 1992 and March 2001. The 230 patients, treated between December 1992 and December 1997 were analyzed. All patients underwent laparoscopic pelvic lymph node dissection to exclude patients with lymphatic involvement. Ir 192 was delivered twice with a 1-week interval in HDR remote control technique. The interstitial dose from December 1992 to December 1993 was 10Gy, after December 1993 the dose was reduced to 9Gy per treatment session. The interstitial application was followed by external beam radiation of 45Gy for cT1–cT2 and 50.4Gy for cT3 tumor (40Gy from December 1992 to December 1993). Progression was defined as biochemical failure according to ASTRO criteria, e.g. three consecutive PSA rises following the PSA nadir. Results: The median PSA value decreased from 12.8 to 0.93ng/ml 12 months after treatment. Median PSA value was 0.47 after 24 months, 0.30ng/ml after 36 months and 0.18ng/ml after 60 months. 68% of the biopsies were negative 24 months after therapy. Progression-free rate was 100% for cT1 tumors, 75% for cT2 and 60% for stage-cT3 on 5-year follow-up. Five-year overall survival was 93%, 5-year disease-specific survival was 98%. Initial PSA value Conclusions: Combined HDR brachytherapy with Ir 192 is an alternative treatment option especially for patients with cT3 prostate cancer. Initial PSA value, stage and grade, are important prognostic factors.

Multigene analysis of Rb pathway and apoptosis control in esophageal squamous cell carcinoma identifies patients with good prognosis

Deregulation of cell‐cycle G1‐restriction point control by disruption of Rb‐pathway components is a frequent event in cancer. In concert with the inactivation of cell death pathways, such events not only contribute to tumor development but also determine the intrinsic and acquired resistance to cancer therapy and, ultimately, disease prognosis. We previously observed that the cyclin‐dependent kinase inhibitor p16INK4a and the proapoptotic Bcl‐2 homolog Bax are positive prognostic factors and identify patients with good prognosis in esophageal squamous cell carcinoma (SCC). In the present study, we therefore extend our analysis to additional genes controlling the G1 restriction point and apoptosis, respectively. This retrospective analysis was performed in a cohort of 53 patients undergoing surgery for esophageal SCC with curative intent, i.e., R0 resection. Protein expression profiles of cyclin D1, p16INK4a, Rb, p21CIP/WAF‐1, p53, Bax and Bcl‐2 were analyzed by immunohistochemistry and compared to p53 mutational status, as determined by SSCP‐PCR of exons 5–8. Loss of p16INK4a, Rb, p21CIP/WAF‐1 or Bax and overexpression of cyclin D1 were associated individually with shorter overall survival, while Bcl‐2 expression and p53 mutation were not of prognostic relevance. The longest survival was observed in a subgroup of patients whose tumors bore a combination of favorite genotypes, i.e., low cyclin D1 and high Rb, p21CIP/WAF‐1, p16INK4a and Bax protein expression. These results show that multigene analyses based on limited sets of functionally linked genes reliably identify patients with good vs. poor prognosis.

Temperature data and specific absorption rates in pelvic tumours: predictive factors and correlations

The system BSD 2000 has been in clinical use for regional hyperthermia for more than 10 years. Several technical details of this hyperthermia system, as well as the results of clinical studies employing this system have been investigated. The intention of this paper is to investigate the correlation between technical efficiency or feasibility of hyperthermia with the BSD 2000, in terms of power densities and temperatures depending upon parameters such as tumour histology, tumour location, patient age, patient sex, and patient cross section. The possible conclusions of predictive factors derived from the above correlations were closely scrutinized. Data acquired from 772 treatment sessions of 190 patients with pelvic tumours, mainly sarcomas and carcinomas of the rectum, cervix, prostate and anus, have been evaluated. For every session, index temperatures T90 (temperature attained at 90% of tumour related measurement points), cumulative minutes for T90 > Tref, tumour related power density (SAR: specific absorption rate, in W/kg) and the effective perfusion Weff (in ml/100 g min) were calculated. Temperatures were measured either invasively or endoluminally. The statistics software SPSS was employed subsequently for univariate, as well as multivariate analyses. The results exhibit that index temperatures mainly depend on the power density SAR and the hyperthermia induced effective perfusion. The total power P (in 100 W) and, complementarily, the relative power density absolute value(SAR) (= SAR/P) seem to have lesser influence. Clear differences between the tumour entities were established regarding their index temperatures and temperature distributions. SAR, Weff and P were correlated with several anatomical, biological and clinical factors. Sessions rendering low index temperatures and SAR values also revealed decreased individual tolerance to the treatment. This clearly displays that power-induced side effects define the limits of the efficiency of regional hyperthermia. Equivalent relationships and correlations are derived from intratumoural and endoluminal thermometry. Individual limitations of regional hyperthermia caused by anatomical, biological and clinical factors are liable to be difficult to overcome with the rather restricted potentials of the BSD 2000 system to control the SAR distribution.The system BSD 2000 has been in clinical use for regional hyperthermia for more than 10 years. Several technical details of this hyperthermia system, as well as the results of clinical studies employing this system have been investigated. The intention of this paper is to investigate the correlation between technical efficiency or feasibility of hyperthermia with the BSD 2000, in terms of power densities and temperatures depending upon parameters such as tumour histology, tumour location, patient age, patient sex, and patient cross section. The possible conclusions of predictive factors derived from the above correlations were closely scrutinized. Data acquired from 772 treatment sessions of 190 patients with pelvic tumours, mainly sarcomas and carcinomas of the rectum, cervix, prostate and anus, have been evaluated. For every session, index temperatures T 90 (temperature attained at 90% of tumour related measurement points), cumulative minutes for T90 > Tref, tumour related power density (SAR: specific absorption rate, in W/kg) and the effective perfusion Weff (inml/100gmin) were calculated. Temperatures were measured either invasively or endoluminally. The statistics software SPSS was employed subsequently for univariate, as well as multivariate analyses. The results exhibit that index temperatures mainly depend on the power density SAR and the hyperthermia induced effective perfusion. The total power P (in 100W) and, complementarily, the relative power density ||SAR|| (= SAR/P) seem to have lesser influence. Clear differences between the tumour entities were established regarding their index temperatures and temperature distributions. SAR, Weff and P were correlated with several anatomical, biological and clinical factors. Sessions rendering low index temperatures and SAR values also revealed decreased individual tolerance to the treatment. This clearly displays that powerinduced side effects define the limits of the efficiency of regional hyperthermia. Equivalent relationships and correlations are derived from intratumoural and endoluminal thermometry. Individual limitations of regional hyperthermia caused by anatomical, biological and clinical factors are liable to be difficult to overcome with the rather restricted potentials of the BSD 2000 system to control the SAR distribution.

Interstitial Hyperthermia using Self-Regulating Thermoseeds Combined with Conformal Radiation Therapy

Abstract Objective: The combination of hyperthermia and radiation in the treatment of malignancies is based on a variety of experimental data which have proven the synergistic effects of these two treatment modalities. We planned a phase II trial in a special hyperthermia research group (SFB 273) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to determine feasibility, acute toxicity and efficacy of this combination for prostate cancer. Methods: A total of 57 patients with localized prostate cancer were treated with interstitial hyperthermia using cobalt-palladium thermoseeds and conformal radiation between July 1997 and December 2000. Thermoseeds were placed into the prostate homogeneously. Hyperthermia was created using a magnetic field and was delivered in six sessions once weekly. 3D-conformal radiotherapy of 68.4Gy was given simultaneously in daily fractions of 1.8Gy. Results: Intra-prostatic temperatures were between 42 and 46°C. No major side effects were observed during hyperthermia. Median follow-up was 12 months (range: 3–26 months). Median prostate specific antigen (PSA) value decreased from 11.6 to 2.4ng/ml 3 months after treatment, to 1.3ng/ml 12 months after treatment and to 0.55ng/ml 2 years after the therapy. Conclusion: Interstitial hyperthermia is feasible, well tolerated and led to a steep decrease of PSA values. Our current follow-up is too short to comment about efficacy. Combining effective interstitial hyperthermia with conformal radiotherapy may be an exciting innovative treatment option for prostate cancer.

Combined treatment of inoperable carcinomas of the uterine cervix with radiotherapy and regional hyperthermia

AimThe disappointing results for inoperable, advanced tumors of the uterine cervix after conventional radiotherapy alone necessitates improving of radiation therapy. Simultaneous chemotherapy or altered radiation fractionation, such as accelerated regimen, increase acute toxicity and treatment is often difficult to deliver in the planned manner. The purpose of this phase II study was to investigate the toxicity and effectiveness of a combined approach with radiotherapy and regional hyperthermia.Patients and MethodsFrom January 1994 to October 1995 18 patients with advanced carcinomas of the uterine cervix were treated in combination with radiotherpay and hyperthermia. The patients were treated with 6 to 20 MV photons delivered by a linear accelerator in a 4-field-box technique to a total dose of 50.4 Gy in 28 fractions. In the first and fourth week 2 regional hyperthermia treatments were each applied with the Sigma-60 applicator from a BSD-2000 unit. After this a boost to the primary tumor was given with high-dose-rate iridium-192 brachytherapy by an afterloading technique with 4×5 Gy at point A to a total of 20 Gy and for the involved parametrium anterioposterior-posterioanterior to 9 Gy in 5 fractions.ResultsThe acute toxicity was low and similar to an external radiotherapy alone treatment. No Grade III/IV acute toxicity was found. The median age was 47 years (range 34 to 67 years). In 16 of 18 patients a rapid tumor regression was observed during combined thermo-radiotherapy, which allowed the use of intracavitary high-dose-rate brachytherapy in these cases. Complete and partial remission were observed in 13 and 4 cases, respectively. One paitent die not respond to the treatment. The median follow-up was 24 months (range 17 to 36 months). The local tumor control rate was 48% at 2 years. Median T20, T50 and T90 values were 41.7°C (range 40.3 to 43.2°C), 41.1°C (range 39.2 to 42.5°C) and 39.9°C (range 37.7 to 41.9°C), respectively. Cumulative minutes of T90>40°C (Cum40T90) and cumulative minutes, which were isoeffective to 43°C, were calculated (CEM43T90, CEM43T50, CEM43T20). CEM43T90 was found to be a significant parameter in terms of local tumor control for the 4 hyperthermia treatments (p=0.019).Conclusion sThis treatment modality has proved to be feasible and well tolerable. The rapid tumor shrinkage in the combined approach of radiotherapy with hyperthermia before beginning brachytherapy seems to be a good prerequisite for improving of the disappointing results in cure of advanced cancer of the uterine cervix.ZusammenfassungZielDie unbefriedigenden Ergebnisse lokal fortgeschrittener, inoperabler Tumoren der Cervix uteri nach konventioneller Strahlentherapie machen eine Intensivierung der Therapie erforderlich. Simultane Chemotherapie oder akzelerierte Fraktionierungsschemata erhöhen meist die akute Toxizität, so daß die Therapie in der geplanten Form nur schwer durchgeführt werden kann. Das Ziel dieser Phase-II-Studie wares, Toxizität und Effektivität der kombinierten Strahlentherapie und regionalen Hyperthermie zu untersuchen.Patienten und MethodenVon Januar 1994 bis Oktober 1995 wurden 18 Patientinnen mit lokal fortgeschrittenen Karzinomen der Cervix uteri mit einer kombinierten Strahlentherapie und regionalen Hyperthermie behandelt. Die Patientinnen wurden mit 6-bis 20-MV-Photonen eines Linearbeschleunigers in einer 4-Felder-Box-Technik bis zu einer Gesamtdosis von 50,4 Gy in 28 Fraktionen bestrahlt. Während der ersten und vierten Woche erfolgten jeweils zwei regionale Hyperthermiebehandlungen mit dem Sigma-60-Applikator eines BSD-2000-Gerätes. Nach 50,4 Gy wurde ein Brachytherapie-Boost auf den Primärtumor mit HDR-Iridium 192 in Afterloading technik (4×5 Gy am Punkt A) bis zu einer Dosis von 20 Gy gegeben. Die initial befallenen Parametrien erhielten eine perkutane Dosiserhöhung um 9 Gy in fünf Fraktionen über ventrodorsale Gegenfelder.ErgebnisseDie akute Toxizität war gering, Nebenwirkungen Grad 3 oder 4 wurden nicht beobachtet. Das mediane Alter betrug 47 Jahre (Altersspanne 34 bis 67 Jahre). Bei 16 von 18 Patientinnen wurde eine rasche Tumorregression während der kombinierten Hyperthermie und Strahlentherapie beobachtet, wodurch die intrakavitäre Brachytherapie in diesen Fällen ermöglicht wurde. Eine komplette Remission wurde in 13 Fällen erreicht, viermal eine partielle Remission, in einem Fall erfolgte keine Reaktion. Die mediane Nachbeobachtungszeit betrug 24 Monate (17 bis 36 Monate). Nach zwei Jahren waren 48% der Tumoren lokal kontrolliert. Die medianen T20-, T50-und T90-Werte lagen bei 41,7°C (40,3 bis 43,2°C), 41,1°C (39,2 bis 42,5°C) und 39,9°C (37,7 bis 41,9°C). Zusätzlich wurden die kumulativen Minuten der T90-Werte über 40°C (Cum40T90) und die kumulativen Minuten, die isoeffektiv zu 43°C waren (CEM43T90, CEM43T50, CEM43T20), kalkuliert. Die CEM43T90-Werte für alle vier Hyperthermiebehandlungen waren ein signifikanter prognostischer Parameter in bezug auf die lokale Tumorkontrolle (p=0,019).Schlußfolgerung enDie beschreibene Therapie erwies sich als durchführbar und gut verträglich. Die gute Tumorregression während der kombinierten Therapie bis zum Beginn der Brachytherapie stellt eine günstige Voraussetzung zur Verbesserung der Heilungsergebnisse dieser lokal fortgeschrittenen Tumoren dar.

Thermoradiotherapie mit interstitiellen Thermoseeds bei der Behandlung des lokalen Prostatakarzinoms Erste Ergebnisse einer Phase-II-Studie

ZusammenfassungIm Rahmen des Sonderforschungsbereichs Hyperthermie (273) der Deutschen Forschungsgemeinschaft wurde eine Phase-II-Studie initiiert, um die Effektivität der interstitiellen Hyperthermie in Kombination mit konformaler Strahlentherapie beim lokalen Prostatakarzinom zu ermitteln. Zwischen Juli 1997 und April 2000 konnten 41 Patienten rekrutiert werden.Die interstitielle Hyperthermie wurde mittels Kobalt-Palladium-Seeds in einem magnetischen Feld erzeugt. Die perkutane konformale Strahlentherapie begann simultan zur Hyperthermie. Die tägliche fraktionierte Dosis betrug 1,8 Gy und die Gesamtdosis 68,4 Gy. Während der Therapie kam es zu keiner Grad-III- oder -IV-Nebenwirkung. Der mediane initiale PSA-Wert fiel in einem medianen Beobachtungszeitraum von 10 Monaten von 11,25 ng/ml auf 0,88 ng/ml 3 Monate nach Therapie und auf 0,38 ng/ml 12 Monate nach Therapie ab.Wir konnten nachweisen, dass die interstitielle Hyperthermie mit Thermoseeds durchführbar und die Kombination mit der konformalen Strahlentherapie verträglich ist. Ein längerer Beobachtungszeitraum ist erforderlich, um die Effizienz dieser Kombination zu beurteilen.AbstractSeveral experimental data are available regarding the efficacy of the combination of interstitial hyperthermia and conformal radiation therapy. We planned a phase II trial as a member of the special hyperthermia research group of the Deutsche Forschungsgemeinschaft (German Research Society) to determine the efficacy of thermoradiotherapy using interstitial cobalt-palladium thermoseeds in the treatment of patients with localized prostate cancer.Forty-one patients with localized prostate cancer were enrolled in the study between July 1997 and April 2000. The interstitial hyperthermia induced in a magnetic field was applied in six sessions once a week. Conformal three-dimensional radiation therapy was given simultaneously in daily fractions of 1.8 Gy with a total dose of 68.4 Gy. We measured intraprostatic temperatures between 42° and 46°C. No major side effects were observed during the hyperthermia session. The median level of prostate-specific antigen (PSA) decreased from 11.25 ng/ml to 0.88 ng/ml 3 months after treatment and to 0.38 ng/ml 12 months after treatment with a median follow-up of 10 months. The mean prostate volume decreased from 32.6 ml to 26 ml after 3 months of treatment and to 18.5 ml after 12 months.Interstitial hyperthermia is a feasible, well-tolerated procedure in prostate cancer therapy. A significant PSA decrease was observed. Longer follow-up is necessary to determine the efficacy.

Vergleich unterschiedlicher dreidimensionaler Bestrahlungstechniken bei der lokalen Strahlentherapie des Prostatakarzinoms

ZielVier verschiedene SD-Bestrahlungstechniken wurden hinsichtlich der Dosishomogenität im Targetvolumen und der Dosis-Volumen-Belastung der Risikoorgane in AbhÄngigkeit vom Tumorstadium untersucht.Patienten und MethodeBei 17 Patienten wurden eine 3D-Rotations-, Vier-Felder-, Fünf-Felder- und Sechs-Felder-Technik erstellt. Sechs Patienten wiesen ein Stadium T1N0M0, sieben Patienten ein Stadium T2N0M0 und vier Patienten ein Stadium T3N0M0 auf. Dosiert wurde auf den Referenzpunkt im Isozentrum (100%). Die 95%-Isodose mu\te das Planungszielvolumen umschlie\en. Es wurden bei allen Techniken Multileaf-Kollimatoren verwendet und Dosis-Volumen-Histogramme für das Planungszielvolumen und die Risikoorgane (Blase, Rektum, Hüftköpfe) erstellt und miteinander verglichen. Der Vergleich erfolgte jeweils bei 33%, 50% und 66% Volumen des jeweiligen Risikoorgans.ErgebnisseHinsichtlich der Dosishomogenität im Targetvolumen zeigte sich kein Unterschied. Eine signifikante Differenz wurde bei der Blasenbelastung zwischen der Sechs-Felder- und der Vier-Felder-Technik nur bei 50% Volumenanteil (p = 0,034), zwischen Sechs-Felder- und Rotationstechnik sowie zwischen Fünf-Felder- und Rotationstechnik bei allen Volumenanteilen gesehen. Bei der Belastung des Rektums ergab sich eine signifikante Differenz zwischen der Sechs- und der Vier-Felder-Technik bei T1- und T2-Tumoren sowohl bei 50% (p = 0,033) als auch bei 66% (p = 0,011). Bei den T3-Tumoren ergaben sich hinsichtlich der Rektumbelastung keine signifikanten Unterschiede. Die beste Schonung der Hüftköpfe wurde durch die Rotationstechnik erzielt.Schlu\folgerungBei der kleinvolumigen Bestrahlung der Prostata ist bei T1/2-Tumoren durch die Sechs-Felder-Technik die beste Schonung von Rektum und Blase zu erzielen, bei grö\erem Planungszielvolumen und bei Einschlu\ der SamenblÄschen sollten andere Techniken, wie zum Beispiel eine dreidimensional geplante Vier-Felder-Technik, zur besseren Schonung der Risikoorgane angewendet werden.AbstractPurposeFour different three-dimensional planning techniques for localized radiotherapy of prostate cancer were compared with regard to dose homogeneity within the target volume and dose to organs at risk, dependent upon tumor stage.Patients and MethodsSix patients with stage T1, 7 patients with stage T2 and 4 patients with stage T3 were included in this study. Four different 3D treatment plans (rotation, 4-field, 5-field and 6-field technique) were calculated for each patient. Dose was calculated with the reference point at the isocenter (100%). The planning target volume was encompassed within the 95% isodose surface. All the techniques used different shaped portal for each beam. Dose volume histograms were created and compared for the planning target volume and the organs at risk (33%, 50%, 66% volume level) in all techniques.ResultsThe 4 different three-dimensional planning techniques revealed no differences concerning dose homogeneity within the planning target volume. The dose volume distribution at organs at risk show differences between the calculated techniques. In our study the best protection for bladder and rectum in stage T1 and T2 was achieved by the 6-field technique. A significant difference was achieved between 6-field and 4-field technique only in the 50% volume of the bladder (p = 0.034), between the 6-field and rotation technique (all volume levels) and between 5-field and rotation technique (all volume levels). In stage T1, T2 6-field and 4-field technique in 50% (p = 0.033) and 66% (p = 0.011) of the rectum volume. In stage T3 a significant difference was not observed between the 4 techniques. The best protection of head of the femur was achieved by the rotation technique.ConclusionIn the localized radiotherapy of prostate cancer in stage T1 or T2 the best protection for bladder and rectum was achieved by a 3D-planned conformai 6-field technique. If the seminal vesicles have been included in the target volume and in the case of large planning target volume other techniques should be taken for a better protection for organs at risk e. g. a 3D-planned 4-field technique box technique.PURPOSE Four different three-dimensional planning techniques for localized radiotherapy of prostate cancer were compared with regard to dose homogeneity within the target volume and dose to organs at risk, dependent upon tumor stage. PATIENTS AND METHODS Six patients with stage T1, 7 patients with stage T2 and 4 patients with stage T3 were included in this study. Four different 3D treatment plans (rotation, 4-field, 5-field and 6-field technique) were calculated for each patient. Dose was calculated with the reference point at the isocenter (100%). The planning target volume was encompassed within the 95% isodose surface. All the techniques used different shaped portal for each beam. Dose volume histograms were created and compared for the planning target volume and the organs at risk (33%, 50%, 66% volume level) in all techniques. RESULTS The 4 different three-dimensional planning techniques revealed no differences concerning dose homogeneity within the planning target volume. The dose volume distribution at organs at risk show differences between the calculated techniques. In our study the best protection for bladder and rectum in stage T1 and T2 was achieved by the 6-field technique. A significant difference was achieved between 6-field and 4-field technique only in the 50% volume of the bladder (p = 0.034), between the 6-field and rotation technique (all volume levels) and between 5-field and rotation technique (all volume levels). In stage T1, T2 6-field and 4-field technique in 50% (p = 0.033) and 66% (p = 0.011) of the rectum volume. In stage T3 a significant difference was not observed between the 4 techniques. The best protection of head of the femur was achieved by the rotation technique. CONCLUSION In the localized radiotherapy of prostate cancer in stage T1 or T2 the best protection for bladder and rectum was achieved by a 3D-planned conformal 6-field technique. If the seminal vesicles have been included in the target volume and in the case of large planning target volume other techniques should be taken for a better protection for organs at risk e. g. a 3D-planned 4-field technique box technique.

Brachytherapie des lokalen Prostatakarzinoms

ZusammenfassungDie Brachytherapie des Prostatakarzinoms hat in den letzten Jahren auch in Deutschland mehr Anwendung gefunden. Dabei kommen verschiedene Strahlenquellen in Frage. Diese unterscheiden sich teilweise aufgrund ihrer physikalischen Eigenschaften. Es werden permanente oder temporäre Strahlenquellen angewendet. Permanente Quellen sind 125Jod, 103Palladium und 198Gold. Als temporäre Quelle ist 192Iridium vorhanden. Der Erfolg der Brachytherapie ist von der Patienten- und der Isotopenselektion abhängig. Die LDR-Brachytherapie als Monotherapie eignet sich für Low-risk-Patienten mit initialem PSA-Wert ≤10 ng/ml, Tumorstadium maximal T2b und G2 bzw. Gleason-Score ≤6. Bei Patienten mit einem höherem Tumorstadium muss eine Dosiseskalation stattfinden. Ein synergistischer Effekt einer zusätzlichen perkutanen Strahlentherapie oder einer antiandrogenen Therapie zur LDR-Implantation ist noch nicht bewiesen.AbstractBrachytherapy of prostate cancer has become attractive in recent years in Germany. There are several radioactive sources available, which are physically different. Some of them are used as permanent or temporary implants. The permanent sources most frequently used are iodine 125, palladium 103, and gold 198. Iridium is a temporary implant.The techniques used in Germany are low-dose rate (LDR) and high-dose rate brachytherapy, which differ in dose distribution and patient population.The success of prostate cancer brachytherapy depends on patient selection and choosing the right source for the technique used. Best suited for LDR monotherapy is the low-risk patient with a prostate-specific antigen (PSA) level below 10 ng/ml, maximal tumor stage T2b, and a Gleason score of less than 7.