Christos Kolotas

CT-Based Interstitial HDR Brachytherapy

Purpose: Development, application and evaluation of a CT-guided implantation technique and a fully CT-based treatment planning procedure for brachytherapy. Methods and Materials: A brachytherapy procedure based on CT-guided implantation technique and CT-based treatment planning has been developed and clinical evaluated. For this purpose a software system (PROMETHEUS) for the 3D reconstruction of brachytherapy catheters and patient anatomy using only CT scans has been developed. An interface for the Nucletron PLATO BPS treatment planning system for optimization and calculation of dose distribution has been devised. The planning target volume(s) are defined as sets of points using contouring tools and are used for optimization of the 3D dose distribution. Dose-volume histogram based analysis of the dose distribution (COIN analysis) enables a clinically realistic evaluation of the brachytherapy application to be made. The CT-guided implantation of catheters and the CT-based treatment planning procedure has been performed for interstitial brachytherapy and for different tumor sites in 197 patients between 1996 and 1997. Results: The accuracy of the CT reconstruction was tested using first a quality assurance phantom and second, a simulated interstitial implant of 12 needles. These were compared with the results of reconstruction using radiographs. Both methods gave comparable results with regard to accuracy, but the CT based reconstruction was faster. Clinical feasibility was proved in pre-irradiated recurrences of brain tumors, in pretreated recurrences or metastatic disease, and in breast carcinomas. The tumor volumes treated were in the range 5.1 to 2,741 cm3. Analysis of implant quality showed a slightly significant lower COIN value for the bone implants, but no differences with respect to the planning target volume. Conclusions: The Offenbach system, incorporating the PROMETHEUS software for interstitial HDR brachytherapy has proved to be extremely valuable in routine clinical practice for many tumor sites. Our CT-guided implantation technique together with a fully CT-based planning system has enabled conformal brachytherapy treatment to become routine.Ziel: Entwicklung, Anwendung und Evaluierung einer CT-gesteuerten Implantationstechnik und einer vollständig CT-gestützten Behandlungsplanung für Brachytherapie. Material und Methoden: Es wurde ein Brachytherapieverfahren, basierend auf einer CT-gesteuerten Implantationstechnik und CT-gestützter Bestrahlungsplanung, entwickelt und klinisch evaluiert. Für diese Zielsetzung wurde ein Softwaresystem (PROMETHEUS) zur 3D-Rekonstruktion der Applikatoren und der individuellen anatomischen Verhältnisse unter ausschließlicher Verwendung von CT-Schnittbildern entwickelt. Hierzu wurde ein Interface für das Nucletron-PLATO-BPS-Planungssystem zur Optimierung und Berechnung der Dosisverteilung realisiert. Das Zielvolumen (PTV) wird definiert und zur Optimierung der dreidimensionalen Dosisverteilung verwendet. Die Analyse der Dosisverteilung mittels Dosisvolumenhistogrammen (COIN) ermöglicht eine klinische Bewertung des Brachytherapieverfahrens. Die CT-gesteuerte Katheterimplantation und die CT-gestützte Bestrahlungsplanung zur Behandlung unterschiedlicher Tumoren in verschiedenen anatomischen Regionen wurden bei 197 Patienten in dem Zeitraum 1996 bis 1997 durchgeführt. Ergebnisse: Die Genauigkeit der CT-Rekonstruktion wurde mit Hilfe eines Brachytherapie-QA-Phantoms und eines Implantats mit zwölf Nadeln überprüft. Die Ergebnisse wurden mit denen der konventionellen Rekonstruktion aus Röntgenaufnahmen verglichen. Beide Methoden ergaben vergleichbare Ergebnisse in Hinblick auf die Rekonstruktionsgenauigkeit. Die CT-gestützte Rekonstruktion war jedoch schneller. In der klinischen Anwendung wurden Tumorvolumina zwischen 5,1 und 2 741 cm3 behandelt. Die Auswertung der Bestrahlungspläne ergab einen geringfügig signifikant geringeren COIN-Wert für die Knochenimplantate, aber keine Unterschiede hinsichtlich des Tumorvolumens. Schlußfolgerung: Die entwickelte Offenbacher Methode hat sich in der klinischen Routine zur Durchführung einer CT-gestützten Brachytherapie in unterschiedlichen Tumorlokalisationen bewährt. Unsere CT-gesteuerte Implantationstechnik zusammen mit dem CT-gestützten Planungssystem ermöglicht uns eine konformale Brachytherapiebehandlung.

CT-Guided Interstitial HDR Brachytherapy for Recurrent Glioblastoma Multiforme

Background and Purpose:Recurrences of glioblastoma multiforme (GBM) within previously irradiated volumes pose a serious therapeutic challenge. This retrospective study evaluates the long-term tumor control of recurrent GBM treated with interstitial high-dose-rate brachytherapy (HDR-BRT).Patients and Methods:Between 1995 and 2003, 84 patients were treated for recurrent cerebral GBM located within previously irradiated volumes. All patients had received adjuvant external radiotherapy following primary surgery, with a focal dose up to 60 Gy. The median recurrent tumor volume was 51 cm3 (3–207cm3), and the HDR-BRT consisted of an afterloading 192Ir implant which delivered a median dose of 40 Gy (30–50 Gy). Catheter implantation was implemented using interactive computed tomography (CT) guidance under local anesthesia and sedoanalgesia.Results:After a median follow-up of 61 months, 5/84 patients (6%) were alive. The median post-BRT survival was 37 weeks, and the median overall survival 78 weeks. Moderate to severe complications occurred in 5/84 cases (6%).Conclusion:For patients with recurrences of GBM within previously irradiated volumes, CT-guided interstitial HDR-BRT is a feasible treatment option that can play an important role in providing palliation.Hintergrund und Ziel:Glioblastoma-multiforme-(GBM-)Rezidive innerhalb vorbestrahlter Volumina stellen eine therapeutische Herausforderung dar. Ziel dieser Studie ist die Vorstellung der CT-gestützten interstitiellen High-Dose-Rate-Brachytherapie (HDRBRT) bei der Behandlung zerebraler GBM-Rezidive.Patienten und Methodik:Von 1995 bis 2003 wurden insgesamt 84 Patienten mit rezidiviertem GBM mittels interstitieller HDR-BRT behandelt. Alle Patienten waren voroperiert und hatten im Rahmen der Primärtherapie eine adjuvante perkutane Teilhirnbestrahlung bis 60 Gy erhalten. In der Rezidivsituation erhielten alle eine fraktionierte interstitielle 192Ir-HDR-BRT bis zu einer medianen Gesamtdosis von 40 Gy (30–50 Gy). Die Implantation der BRT-Katheter wurde bei einem medianen Tumorvolumen von 51 cm3 (3–207 cm3) unter CT-Kontrolle in Sedoanalgesie und Lokalanästhesie durchgeführt.Ergebnisse:Bei einer medianen Nachbeobachtung von 61 Monaten betrug das mediane Überleben 37 Wochen vom Zeitpunkt der Brachytherapie sowie 78 Wochen ab Diagnosestellung. Moderate bis schwerwiegende Komplikationen ereigneten sich in 5/84 Fällen (6%).Schlussfolgerung:Die CT-gestützte interstitielle HDR-BRT ist ein wertvolles Instrument für die palliative Behandlung von Patienten mit rezidiviertem GBM.

Reirradiation for Recurrent Neck Metastases of Head-and-Neck Tumors Using CT-Guided Interstitial 192Ir HDR Brachytherapy

Purpose:To report the therapeutic results obtained with CT-guided interstitial high-dose-rate brachytherapy (HDR-BRT) as exclusive treatment for recurrent neck metastases of head-and-neck tumors.Patients and Methods:Between 1995 and 1999, 49 patients with prior radiation therapy (RT) with or without surgery for primary head-and-neck tumors were treated for recurrent neck metastases located within previously irradiated volumes. All patients had fixed lymphadenopathy with a mean tumor volume of 96 cm3 (range, 15–452 cm3). There were 38 males and eleven females with a mean age of 60 years (range, 28–79 years). All patients had previously received RT as primary or adjuvant treatment with a mean dose of 54 Gy (range, 45–80 Gy). 36 patients (73%) underwent surgery, and 26 (53%) received adjuvant or palliative chemotherapy. The accelerated hyperfractionated interstitial HDR-BRT (2 × 3.0 Gy/day) delivered 30 Gy in 37/49 (75%) and 36 Gy in 12/49 implants (25%).Results:At a minimum 6-week follow-up, the response rate was 83% (41/49) with complete remission in 20% (10/49) and partial remission in 63% (31/49) of the implanted tumor sites. 8/49 patients (17%) did not respond to the treatment. After 19 months of median follow-up, the local control rate was 69% and a total of 15/49 patients (30%) experienced local disease progression. Of these, nine (18%) had locoregional progression and six (12%) progression within the treated volume. The median post-BRT survival was 14 months. The overall survival rate was 52% at 1 year, 31% at 2 years, and 6% at 3 years.Conclusion:In patients with recurrent cervical lymphadenopathy of head-and-neck tumors, exclusive interstitial HDR-BRT can provide palliation and tumor control.Ziel:Vorstellung der CT-gestützten interstitiellen High-Dose-Rate-Brachytherapie (HDR-BRT) als ausschließliches Therapieverfahren in der Behandlung zervikaler Lymphknotenrezidive von Kopf-Hals-Tumoren.Patienten und Methodik:Zwischen 1995 und 1999 wurden insgesamt 49 Patienten mit zervikalen Lymphknotenrezidiven behandelt. Alle 49 Patienten (38 männlich, elf weiblich, Durchschnittsalter 60 Jahre [28–79 Jahre]) waren mit einer durchschnittlichen Zielvolumendosis von 54 Gy (45–80 Gy) vorbestrahlt, und 36 (73%) waren voroperiert. Eine adjuvante oder palliative Chemotherapie war bei 26 Patienten (53%) durchgeführt worden. Alle Patienten erhielten eine akzeleriert-hyperfraktionierte BRT (2 × 3 Gy/Tag) bis zu einer Gesamtdosis von 30 Gy in 37/49 (75%) und 36 Gy in 12/49 Implantaten (25%). Das durchschnittliche Tumorvolumen betrug 96 cm3 (15–452 cm3).Ergebnisse:Die Ansprechrate nach 6 Wochen betrug 83%. Bei 10/49 Patienten (20%) wurde eine komplette Remission, bei 31/49 (63%) eine partielle Remission erzielt. 8/49 (17%) zeigten kein Ansprechen bzw. eine lokale Progredienz. Nach einer medianen Nachbeobachtungszeit von 19 Monaten betrug die lokale Kontrollrate 69%, bei 15/49 Patienten (30%) lag ein Tumorprogress vor. Dabei zeigten 9/15 (60%) eine lokoregionäre Progression. Lediglich bei 6/15 (40%) handelte es sich um echte In-loco-Rezidive, die innerhalb des BRT-Volumens gelegen waren. Das mediane Überleben betrug 14 Monate, die Gesamtüberlebensrate nach 1 Jahr 52%, nach 2 Jahren 31% und nach 3 Jahren 6%.Schlussfolgerung:Die CT-gestützte interstitielle HDR-BRT ist ein wertvolles Instrument für die palliative Behandlung von Patienten mit Halslymphknotenrezidiven bei Kopf-Hals-Tumoren.

New interstitial HDR brachytherapy technique for prostate cancer: CT based 3D planning after transrectal implantation

We have developed a new interstitial HDR brachytherapy technique for the treatment of prostate cancer using CT based 3D planning after transrectal implantation of four non-parallel needles. CT based needle reconstruction, target definition, evaluation and documentation, including DVHs and 3D imaging, is a feasible, safe and well tolerated treatment concept.

Comparison of calibration procedures for 192Ir high-dose-rate brachytherapy sources.

PURPOSE To compare the efficacy of different calibration procedures for 192Ir high-dose-rate (HDR) brachytherapy sources and to determine their suitability in clinical practice. In addition the manufacturers calibration is compared with our experimental measurements so that the accuracy of the source strength on the manufacturer certificate which is supplied with each new 192Ir source can be accessed. METHODS AND MATERIALS We compared three types of calibration system: well-type chambers (HDR-1000 and SDS), cylindrical phantom, and plate phantom. The total number of measurements we obtained was 365. The number of sources used for the calibration procedure comparison was 20 and the number used for comparison with the manufacturers calibration was 46. This study was made during the period 1989-1997. Also, Physikalisch-Technische Bundesanstalt (PTB) calibrated one of our sources using their PTB protocol so that the results could be compared with our own. RESULTS The sensitivity of each system on scattering from the room walls was studied. It was found that different minimum lateral distances from the walls were required for the different systems tested: 15 cm and 25 cm for the well-type chambers, 75 cm for the cylindrical phantom, and 13 cm for the plate phantom. The minimum thickness required to reach phantom scattering saturation for the plate phantom setup is 24 cm. The influence of the applicator material used in the calibration setup was found to be 1.7% for the stainless steel dosimetry applicator compared to the plastic 5F applicator. The accuracy of source positioning within the applicator can lead to dosimetric errors of +/-1.2% for the radial distance of 8.0 cm used with both solid phantoms. The change in the response for both well-type chambers was only 0.1% for changes in the source position within +/-7.5 mm around the response peak. Good agreement was found between all dosimetry systems included in our study. Taking the HDR-1000 well-type chamber results as a reference, we observed percentage root mean square (RMS) values of 0.11% for the SDS well-type chamber, 0.44% for the cylindrical, and 0.60% for the plate phantom setup. A comparison of our results using the cylindrical phantom with those of the manufacturer showed a percentage RMS value of 3.3% with a percentage fractional error range of -13.0% to +6.0%. The comparison of our calibration results with those of PTB gave deviations less than 0.4% for all systems. CONCLUSIONS Our results have shown that with careful use of all calibration system protocols an accurate determination of source strength can be obtained. However, the manufacturers calibration is not accurate enough on its own, and it should be mandatory for clinics to always measure the source strength of newly delivered 192Ir brachytherapy sources. The influence of the applicator material, metal or plastic, should always be taken into account.

3D Interstitial HDR Brachytherapy Combined with 3D External Beam Radiotherapy and Androgen Deprivation for Prostate Cancer Preliminary Results

Background: Evaluation of feasibility, tolerance and efficiency for a new 3D interstitial HDR brachytherapy technique combined with 3D external beam radiotherapy and androgen deprivation for prostate cancer. Patients and Methods: Between January 1997 and August 1998 we treated 35 patients with Stage cT1–3 N0 M0 prostate cancer. Thirty-two patients with a follow-up of 12 to 28 months (median: 18 months) were evaluated. After ultrasound-guided transrectal implantation of 4 non-parallel needles, CT based 3D brachytherapy treatment planning (“Offenbach system”) was performed. All patients received 4 fractions brachytherapy using a fractional dose of 5 or 7 Gy. Time between each fraction was 14 days. After brachytherapy 3D external irradiation followed up to 39.6 or 45.0 Gy. All patients received androgen deprivation, starting 2 to 19 months before brachytherapy, ending 3 months after 3D external radiotherapy. Results: Posttreatment PSA levels dropped to < 1.5 ng/ml in 29/32 patients (91%). In 25 patients PSA levels were < 0.5 ng/ml, in 4 patients 0.5 to 1.5 ng/ml. In 2 patients we noted biochemical relapse. Transrectal implantation was very well tolerated. Grade 3 acute urinary toxicity occurred in 1 patient. We noted no Grade 2 or higher acute gastrointestinal toxicity. One patient developed a Grade 3 late urinary toxicity. No patient showed late gastrointestinal side effects. All 140 dose-volume histograms for 3D HDR brachytherapy were analyzed. Conclusions: The new 3D HDR brachytherapy technique, combined with 3D external irradiation and androgen deprivation, is a feasible, so far well tolerated and effective treatment in the short-time follow-up of median 18 months.Hintergrund: Auswertung der Praktikabilität, Verträglichkeit und Effektivität einer neuen interstitiellen 3D-HDR-Brachytherapie-Technik, kombiniert mit externer 3D-Radiotherapie und Androgendeprivation beim Prostatakarzinom. Patienten und Methoden: Von Januar 1997 bis August 1998 behandelten wir 35 Patienten mit Prostatakarzinomen im Stadium cT1–3 N0 M0. Die Daten von 32 Patienten mit einer Nachbeobachtungszeit von zwölf bis 28 Monaten (median: 18 Monate) wurden ausgewertet. Nach ultraschallgesteuerter transrektaler Implantation von vier nicht parallelen Nadeln erfolgte die CT-gestützte 3D-Brachytherapie-Planung (“Offenbach-System”). Alle Patienten erhielten vier Fraktionen der 3D-Brachytherapie mit einer Einzeldosis von 5 oder 7 Gy im Abstand von jeweils 14 Tagen. Anschließend erfolgte die externe 3D-Radiotherapie bis 39,6 oder 45,0 Gy. Alle Patienten erhielten zusätzlich eine Androgendeprivation, die zwei bis 19 Monate vor der Brachytherapie eingeleitet und drei Monate nach Abschluss der externen Radiotherapie abgesetzt wurde. Ergebnisse: Bei 29/32 Patienten (91%) sank der posttherapeutische PSA-Wert unter 1,5 ng/ml, davon bei 25 Patienten auf unter 0,5 ng/ml, bei vier Patienten auf 0,5 bis 1,5 ng/ml. Zwei Patienten entwickelten ein biochemisches Rezidiv. Die transrektale Implantation wurde sehr gut toleriert. Ein Patient entwickelte akute Grad-3-Toxizitäten des Harntraktes, kein Patient akute gastrointestinale Nebenwirkungen größer als Grad 1. Eine Grad-3-Spättoxizität des Harntraktes zeigte ein Patient, gastrointestinale Spättoxizitäten entwickelte kein Patient. Alle 140 Dosis-Volumen-Histogramme der 3D-HDR-Brachytherapie wurden ausgewertet. Schlussfolgerung: Die neue 3D-HDR-Brachytherapie-Technik, kombiniert mit externer 3D-Radiotherapie und Androgendeprivation, stellt eine praktikable, bisher gut verträgliche und effektive Therapiemodalität nach Kurzzeitnachbeobachtung von median 18 Monaten dar.

Hypofractionated accelerated CT-guided interstitial 192Ir-HDR-Brachytherapy as re-irradiation in inoperable recurrent cervical lymphadenopathy from head and neck cancer

BACKGROUND Despite significant improvements in the treatment of head and neck cancer (HNC), lymph node recurrences remain a clinical challenge after primary radiotherapy. The value of interstitial (IRT) brachytherapy (BRT) for control of lymph node recurrence remains unclear. In order to clarify its role a retrospective review was undertaken on the value of computed tomography (CT)-guided IRT high-dose-rate (HDR)-BRT in isolated recurrent disease from HNC. PATIENTS AND METHODS From 2000 to 2007, 74 patients were treated for inoperable recurrent cervical lymphadenopathy. All patients had previously been treated with radical radiotherapy or chemoradiation with or without surgery. The HDR-BRT delivered a median salvage dose of 30.0 Gy (range, 12.0-36.0 Gy) in twice-daily fractions of 2.0-5.0 Gy in 71 patients and of 30.0 Gy (range, 10.0-36.0 Gy) in once-daily fractions of 6.0-10.0 Gy in three patients. RESULTS The overall and disease-free survival rates at one, two and three years were 42%, 19%, 6%, and 42%, 37% and 19%, respectively. The local control probability at one, two and three years was 67% at all three time points. Grade III-IV complications occurred in 13% of patients. CONCLUSIONS In patients with inoperable recurrent neck disease from HNC, hypofractionated accelerated CT-guided IRT-HDR-BRT can play an important role in providing palliation and tumor control.

CT-based software for 3-D localization and reconstruction in stepping source brachytherapy

Describes innovative software for catheter localization and 3D reconstruction in stepping-source brachytherapy applications. The patient information is a set of computed tomography (CT) slices, scanned during the implantation of brachytherapy catheters. Catheter geometry and patient anatomy are exported for use with dose calculation software modules. The errors produced by the system are also encouragingly low. Time savings were achieved compared with other traditional reconstruction techniques. Various automated procedures, 3D graphics and a user-friendly GUI have contributed to providing a powerful, comprehensive software tool that is directly useable in clinical practice.

Navigation system for interstitial brachytherapy

PURPOSE To develop a computed tomography (CT) based electromagnetic navigation system for interstitial brachytherapy. This is especially designed for situations when needles have to be positioned adjacent to or within critical anatomical structures. In such instances interactive 3D visualisation of the needle positions is essential. METHODS AND MATERIALS The material consisted of a Polhemus electromagnetic 3D digitizer, a Pentium 200 MHz laptop and a voice recognition for continuous speech. In addition, we developed an external reference system constructed of Perspex which could be positioned above the tumour region and attached to the patient using a non-invasive fixation method. A specially designed needle holder and patient bed were also developed. Measurements were made on a series of phantoms in order to study the efficacy and accuracy of the navigation system. RESULTS The mean navigation accuracy of positioning the 20.0 cm length metallic needles within the phantoms was in the range 2.0-4.1 mm with a maximum of 5.4 mm. This is an improvement on the accuracy of a CT-guided technique which was in the range 6.1-11.3 mm with a maximum of 19.4 mm. The mean reconstruction accuracy of the implant geometry was 3.2 mm within a non-ferromagnetic environment. We found that although the needles were metallic this did not have a significant influence. We also found for our experimental setups that the CT table and operation table non-ferromagnetic parts had no significant influence on the navigation accuracy. CONCLUSIONS This navigation system will be a very useful clinical tool for interstitial brachytherapy applications, particularly when critical structures have to be avoided. It also should provide a significant improvement on our existing technique.

Palliative interstitial HDR brachytherapy for recurrent rectal cancer. Implantation techniques and results.

Purpose: To report the methods and clinical results of CT-based interstitial high-dose-rate (HDR) brachytherapy procedures for the palliative treatment of recurrent rectal cancer. Patients and Methods: A total of 44 brachytherapy implants were performed in 38 patients. CT-guided catheter implants were performed in 34 patients under local anesthesia and sedation, and four patients were implanted intraoperatively. Of 40 CT-guided implants, 20 were done using metallic needles introduced via the sacrum and 20 were transperineal implants of plastic tubes in the presacral region. Postimplant CT scans were used for three-dimensional (3-D) conformal brachytherapy planning. Patients implanted with metallic needles were given a single fraction of 10–15 Gy using HDR 192Ir, and those who received transperineal implants of plastic catheters were given fractionated brachytherapy, 5 Gy twice daily to a total dose of 30–40 Gy. The median tumor volume was 225 cm3 with a range of 41–2,103 cm3. Results: After a median follow-up of 23.4 months, a total of 13/38 patients were alive. The median postbrachytherapy survival was 15 months with 18 of the 25 deaths due to distant metastases. Tumor response was as follows: 6/38 partial remission, 28/38 stable disease, and 4/38 local progression. A planning target volume (PTV) coverage > 85% was achieved in 42/44 implants. The treatment was well tolerated, and no acute complications were observed. One patient developed a fistula after 8 months. Pain relief was recorded in 34 patients (89.5%), and the median duration of this palliative effect was 5 months with a range of 1–13 months. Conclusions: Interstitial HDR brachytherapy is a valuable tool for the delivery of high doses and achieves effective palliation in recurrent rectal carcinoma.Zielsetzung: Beschreibung der Implantationstechniken und Ergebnisse der interstitiellen Brachytherapie in der Behandlung von Rektumkarzinomrezidiven. Patienten und Methodik: Es wurden 44 interstitielle Behandlungen bei 38 Patienten mit einem Rektumkarzinomrezidiv durchgeführt. Bei vier Patienten wurden die Afterloading-Applikatoren intraoperativ platziert. 40 CT-gesteuerte Katheterimplantationen erfolgten bei 34 Patienten unter örtlicher Betäubung und Sedierung. Zwei CT-gesteuerte Techniken wurden angewandt: Von 40 Applikationen wurden 20 als Metallnadeln über das Sakrum (transsakrale Technik) und 20 als Kunststoffkatheter transperineal in die präsakrale Region eingeführt (transperineale Technik). Für die dreidimensionale Brachytherapieplanung schloss sich die Erstellung einer Computertomographie an. Patienten mit Metallnadelimplantaten wurde eine Einzeldosis von 10–15 Gy im High-Dose-Rate-(HDR-)Verfahren (192Ir) appliziert, während jene mit transperinealen Kunststoffimplantaten eine fraktionierte Brachytherapie erhielten (zweimal täglich 5 Gy bis zu einer Gesamtdosis von 30–40 Gy). Das mediane Tumorvolumen betrug 225 cm3 (41–2103 cm3). Ergebnisse: Nach einer medianen Nachbeobachtungszeit von 23,4 Monaten waren 13 von 38 Patienten noch am Leben. Die mediane Überlebenszeit nach der Brachytherapie betrug 15 Monate. 18 der 25 Todesfälle waren Folge der Fernmetastasierung. 6/38 zeigten in der bildgebenden Verlaufsbeobachtung eine partielle Remission und 28/38 “stable disease”. Eine lokale Tumorprogression wurde bei 4/38 Patienten festgestellt. Eine Zielvolumenabdeckung > 85% konnte bei 42 von 44 Bestrahlungsplanungen erzielt werden. Die Behandlung wurde gut vertragen. Akute Komplikationen traten nicht auf. Ein Patient entwickelte 8 Monate nach erfolgter interstitieller HDR-Brachytherapie eine Fistel. Eine Schmerzreduktion gelang bei 34 Patienten (89,5%), die mediane Dauer dieses palliativen Effekts betrug 5 Monate (1–13 Monate). Schlussfolgerungen: Die interstitielle HDR-Brachytherapie ist ein wertvolles Instrument zur Verabreichung hoher lokaler Strahlendosen und erzielt eine effektive Palliation bei Patienten mit nicht kurativ operablem Rektumkarzinomrezidiv.