H. Borchers

Does positron emission tomography using 18-fluoro-2-deoxyglucose improve clinical staging of testicular cancer?— results of a study in 50 patients

OBJECTIVES To compare positron emission tomography (PET) using 18-fluoro-2-deoxyglucose (FDG) with conventional clinical staging in unselected patients with germ cell cancer. METHODS Fifty patients underwent PET scans of the abdomen (n = 50) and chest (n = 41 ) after the initial diagnosis. PET images were evaluated qualitatively and quantitatively using standardized uptake values (SUVs). The results were compared with computed tomography (CT) results and tumor markers (human chorionic gonadotropin, alpha-fetoprotein, and lactate dehydrogenase). Retroperitoneal lymphadenectomy in 12 patients and clinical staging, including follow-up data in all patients, were taken as a reference standard. RESULTS PET detected metastases in 13 (87%) of 15 patients and excluded metastases in 33 (94%) of 35 patients. A sensitivity of 73% and a specificity of 94% were obtained using CT. The respective values for tumor marker determination were 67% and 100%. Retroperitoneal metastases were detected in 2 patients by PET only and in 1 patient by CT only. In the latter patient, surgery of a residual mass after chemotherapy revealed a well-differentiated teratoma. False-negative findings with PET and CT occurred in 2 patients with retroperitoneal metastases approximately 10 mm in size. False-positive findings were due to sarcoidosis or to muscular activity of the neck. Quantitative FDG uptake was very heterogeneous, with an SUV ranging from 1.8 to 17.3. CONCLUSIONS FDG PET has the potential to improve clinical staging of testicular cancer. However, PET, as well as CT, is limited in the detection of small retroperitoneal lymph node metastases.

Health-related quality of life after permanent I-125 brachytherapy and conformal external beam radiotherapy for prostate cancer - a matched-pair comparison

BACKGROUND AND PURPOSE The aim of the study was to compare quality of life after permanent I-125 brachytherapy (BT) and external beam radiotherapy (EBRT) for prostate cancer. MATERIALS AND METHODS A group of 104 patients (52 in each group) have been surveyed prospectively before EBRT/BT (time A), at the last day of EBRT (70.2-72.0 Gy) or one month after BT (time B), and a median time of 16 months after EBRT/BT (time C) using a validated questionnaire (Expanded Prostate Cancer Index Composite). Pairs were matched according to the following criteria: age +/-5 years, prostate volume +/-10 cc, use of antiandrogens, and erectile function. RESULTS Urinary function/bother scores decreased significantly more after BT both at time B and time C. Bowel function/bother scores tended to be higher after BT, with a lower percentage of patients with painful bowel movements (BT: 12%/27%/15%; EBRT: 19%/52%/35% at time A/B/C; p<0.05 for differences at times B/C) and rectal bleeding (BT: 12%/12%/12%; EBRT: 8%/14%/17%). No difference concerning erectile dysfunction was found (67% vs. 61% with preserved erections firm enough for intercourse after BT vs. EBRT at time C). CONCLUSIONS BT was associated with higher urinary, but lower rectal toxicity. The risk of treatment-associated erectile dysfunction did not differ between these methods.

Changes of Dose Delivery Distribution within the First Month after Permanent Interstitial Brachytherapy for Prostate Cancer

Purpose:To evaluate changes of dose distribution for both the prostate and the surrounding tissues after permanent brachytherapy as monotherapy for prostate cancer.Patients and Methods:In 35 patients, CT scans were performed before, 1 day after (day 1) and 1 month after the implantation (day 30). Changes of prostate volume, dosimetric parameters, and distances between posterior prostate contour and rectal wall as well as prostate contour and prescription isodose were analyzed.Results:Prostate volume increased from 37 ± 11 cm3 (mean ± standard deviation) to 49 ± 12 cm3 on day 1 and dropped to 40 ± 9 cm3 on day 30. Prostate V100 increased from 87 ± 7% to 90 ± 7%, prostate D90 from 138 ± 21 Gy to 151 ± 30 Gy. Mean rectal volume covered by the prescription isodose rose from 0.4 cm3 to 1.0 cm3; a changing distance between the prostate and rectal wall was excluded as a reason. Prostate D90 (day 1) and rectum V100 (day 30) proved to be significantly higher for larger prostate sizes. The distance between the prescription isodose and the prostate contour increased particularly at the posterior and inferior borders: 1.9 mm and 2.5 mm on average (0.1 mm and –0.7 mm at opposite borders, respectively).Conclusion:With a decreasing edema of the prostate, an increasing dose both to the prostate and the anterior rectal wall resulted—the postimplant interval is essential for the dosimetry report. Due to a larger edema, a higher prescription dose might be needed for optimal cancer control in smaller prostates. Compared to day 1, the dose to the surrounding tissues increased on day 30, particularly at the posterior and inferior prostate borders.Ziel:Untersuchung von Veränderungen der Dosisverteilung im Bereich der Prostata und des umgebenden Gewebes nach permanenter Brachytherapie als Monotherapie des Prostatakarzinoms.Patienten und Methodik:Bei 35 Patienten wurden CT-Untersuchungen vor, 1 Tag nach (Tag 1) und 1 Monat nach der Implantation (Tag 30) durchgeführt. Veränderungen des Prostatavolumens, dosimetrischer Parameter und des Abstands sowohl zwischen der Prostatakontur und der Rektumwand als auch zwischen der Prostatakontur und der Verschreibungsisodose wurden analysiert.Ergebnisse:Das Prostatavolumen stieg von 37 ± 11 cm3 (Mittelwert ± Standardabweichung) auf 49 ± 12 cm3 am Tag 1 und fiel auf 40 ± 9 cm3 am Tag 30. Prostata-V100 stieg von 87 ± 7% auf 90 ± 7%, Prostata-D90 von 138 ± 21 Gy auf 151 ± 30 Gy. Das mittlere, von der Verschreibungsisodose umschlossene Rektumvolumen vergrößerte sich von 0,4 cm3 auf 1,0 cm3; eine Veränderung des Abstands zwischen Prostata und Rektumwand wurde als Ursache ausgeschlossen. Prostata-D90 (Tag 1) and Rektum-V100 (Tag 30) waren für kleine Prostatagrößen signifikant höher. Der Abstand zwischen der Verschreibungsisodose und der Prostatakontur vergrößerte sich insbesondere am dorsalen und kaudalen Rand: durchschnittlich um 1,9 mm und 2,5 mm (0,1 mm und –0,7 mm am jeweils gegenüberliegenden Rand).Schlussfolgerung:Mit abnehmendem Prostataödem stieg die Dosis im Bereich der Prostata und Rektumvorderwand—das Postimplantationsintervall ist für die Dosisdokumentation essentiell. Wegen eines stärkeren Ödems kann für Patienten mit einer kleineren Prostata für eine optimale Tumorkontrolle eine höhere Verschreibungsdosis notwendig sein. Gegenüber dem Tag 1 erhöhte sich im Bereich des umgebenden Gewebes die Dosis am Tag 30 insbesondere am dorsalen und kaudalen Prostatarand.

Impact of age and comorbidities on health-related quality of life for patients with prostate cancer: evaluation before a curative treatment

BackgroundInterpretation of comparative health-related quality of life (HRQOL) studies following different prostate cancer treatments is often difficult due to differing patient ages. Furthermore, age-related changes can hardly be discriminated from therapy-related changes. The evaluation of age-and comorbidity-related changes was in focus of this study.MethodsHRQOL of 528 prostate cancer patients was analysed using a validated questionnaire (Expanded Prostate Cancer Index Composite) before a curative treatment. Patients were divided into age groups ≤65, 66-70, 71-75 and >75 years. The impact of specific comorbidities and the Charlson Comorbidity Index (CCI) were evaluated. The questionnaire comprises 50 items concerning the urinary, bowel, sexual and hormonal domains for function and bother. For assessment of sexual and hormonal domains, only patients without prior hormonal treatment were included (n = 336).ResultsUrinary incontinence was observed increasingly with higher age (mean function scores of 92/88/85/87 for patients ≤65, 66-70, 71-75 and >75 years) - complete urinary control in 78%/72%/64%/58% (p < 0.01). Sexual function scores decreased particularly (48/43/35/30), with erections sufficient for intercourse in 68%/50%/36%/32% (p < 0.01) - a decrease of more than a third comparing patients ≤65 vs. 66-70 (36%) and 66-70 vs. 71-75 years (39%). The percentage of patients with comorbidities was lowest in the youngest group (48% vs. 66%/68%/63% for ages 66-70/71-75/>75 years; p < 0.05). A multivariate analysis revealed an independent influence of both age and comorbidities on urinary incontinence, specifically diabetes on urinary bother, and both age and diabetes on sexual function/bother. Rectal domain scores were not significantly influenced by age or comorbidities. A CCI>5 particularly predisposed for lower urinary and sexual HRQOL scores.ConclusionUrinary continence and sexual function are the crucial HRQOL domains with age-related and independently comorbidity-related decreasing scores. The results need to be considered for the interpretation of comparative studies or longitudinal changes after a curative treatment.

Health-Related Quality of Life after Permanent Interstitial Brachytherapy for Prostate Cancer

Purpose:To determine dosimetric risk factors for increased toxicity after permanent interstitial brachytherapy for prostate cancer.Patients and Methods:Quality of life questionnaires (Expanded Prostate Cancer Index Composite) of 60 and 56 patients were analyzed after a median posttreatment time of 6 weeks (A—acute) and 16 months (L—late). The corresponding CT scans were performed 30 days after the implant. The prostate, rectal wall, and base of seminal vesicles were contoured. Prostate volume, number of seeds and needles as well as dosimetric parameters were correlated with the morbidity scores.Results:For a prostate volume of 38 ± 12 cm3 (mean ± standard deviation), 54 ± 7 125I sources (Rapid Strands®, activity of 22.6 ± 3.0 MBq [0.61 ± 0.08 mCi]) were implanted using 20 ± 6 needles. Improved late urinary function scores resulted from a higher number of sources per cm3 (≥ 1.35). A prostate D90 < 170 Gy (A)/< 185 Gy (L) and base of seminal vesicle D10 < 190 Gy (A and L) were associated with higher urinary function scores. Late rectal function scores were significantly higher for patients with a prostate V200 < 50% and V150 < 75%. Patients with a prostate volume < 40 cm3 reached better sexual function scores (A and L). A higher number of needles per cm3 (≥ 0.5) resulted in improved late urinary, bowel and sexual function scores.Conclusion:Quality of life after a permanent implant can be improved by using an adequate amount of sources and needles. With an increasing number of seeds per cm3, dose homogeneity is improving. A prostate D90 < 170 Gy and a base of seminal vesicle D10 < 190 Gy (as an indicator of the dose to the bladder neck and urethral sphincter) can be recommended to maintain a satisfactory urinary function.Ziel:Analyse dosimetrischer Risikofaktoren für erhöhte Toxizitätsraten nach permanenter interstitieller Brachytherapie beim Prostatakarzinom.Patienten und Methodik:Fragebögen zur Lebensqualität (Expanded Prostate Cancer Index Composite) von 60 bzw. 56 Patienten wurden 6 Wochen (A—akut) und 16 Monate (S—spät) nach Therapie analysiert. Die entsprechenden Postimplantations-CTs wurden 30 Tage nach der Behandlung durchgeführt. Die Prostata, Rektumwand und Basis der Samenblasen wurden konturiert. Prostatavolumen, Seed- und Nadelanzahl sowie dosimetrische Parameter wurden mit den Punktwerten der Fragebögen korreliert.Ergebnisse:Zur Behandlung eines Prostatavolumens von 38 ± 12 cm3 (Mittelwert ± Standardabweichung) wurden 54 ± 7 125I-Seeds (Rapid Strands®) der Aktivität 22,6 ± 3,0 MBq (0,61 ± 0,08 mCi) über 20 ± 6 Nadeln implantiert. Verbesserte späte Blasenfunktionswerte resultierten bei einer höheren Seedanzahl pro cm3 (≥ 1,35). Ein Prostata-D90-Wert < 170 Gy (A)/< 185 Gy (S) und ein Samenblasen-D10-Wert < 190 Gy (A und S) waren mit verbesserten Blasenfunktionswerten assoziiert. Späte Funktionswerte für den Stuhlgang waren bei Patienten mit Prostata-V200-Werten < 50% und -V150-Werten < 75% signifikant höher. Patienten mit einem Prostatavolumen < 40 cm3 erreichten bessere Werte in der Sexualität (A und S). Eine höhere Nadelanzahl pro cm3 (≥ 0,5) resultierte in verbesserten späten Funktionswerten in allen Domänen.Schlussfolgerung:Die Lebensqualität nach permanenter Brachytherapie kann durch den Einsatz einer adäquaten Menge Seeds und Nadeln verbessert werden. Mit höherer Seedanzahl pro cm3 verbessert sich die Homogenität der Dosisverteilung. Ein Prostata-D90-Wert < 170 Gy und ein Samenblasen-D10-Wert < 190 Gy (als ein Indikator für die Dosisbelastung im Bereich des Blasenhalses und des Sphinkters) können zur Erhaltung einer guten Blasenfunktion empfohlen werden.

Seed Displacements after Permanent Brachytherapy for Prostate Cancer in Dependence on the Prostate Level

Purpose:To evaluate seed displacements after permanent prostate brachytherapy considering different prostate levels.Patients and Methods:In 61 patients, postimplant CT scans were performed 1 day and 1 month after an implant with stranded seeds. Seed and prostate surface displacements were determined relative to pelvic bones. Four groups of seed locations were selected: seeds at the base (n = 305; B), at the apex (n = 305; A), close to the urethra (n = 306; U), and close to the rectal wall (n = 204; R). The length of two strands (always containing four seeds) per patient was measured in all CT scans and compared.Results:The largest inferior seed displacements were found at the base: mean 5.3 mm (B), 2.2 mm (A), 2.7 mm (U), 3.3 mm (R; p < 0.001). Posterior displacements predominated both at the base and the central region: mean 2.2 mm (B), 2.0 mm (U), 0.8 mm (A), –0.6 mm (R; p < 0.001). With a decreasing edema between day 1 and 30 (mean prostate volume of 51 cm3 vs. 41 cm3; p < 0.001), a mean caudal prostate base displacement of 3.9 mm was found, whereas the mean inward displacement ranged from 1.2 to 1.6 mm at the remaining borders (lateral, anterior, posterior, apical). The analysis of the strand lengths revealed an implant compression between day 1 and 30 (mean 1.7 mm; p < 0.001).Conclusion:The largest prostate tissue and seed displacements were observed at the prostate base, associated with an implant compression. Predominantly inferior and posterior displacements implicate consequential smaller preplanning margins at the apex and the posterior prostate.Ziel:Untersuchung von Seedverschiebungen nach permanenter Brachytherapie der Prostata in Abhängigkeit vom Prostatalevel.Patienten und Methodik:Bei 61 Patienten wurden CT-Untersuchungen zur Nachplanung 1 Tag und 1 Monat nach der Strandimplantation durchgeführt. Verschiebungen der Seeds und der Prostataoberfläche wurden relativ zum Beckenskelett bestimmt. Vier verschiedene Gruppen von Seeds wurden unterschieden: Seeds an der Basis (n = 305; B), am Apex (n = 305; A), nahe der Urethra (n = 306; U) und nahe der Rektumwand (n = 204; R). Die Länge von zwei Strands (immer vier Seeds beinhaltend) pro Patient wurde in allen CT-Untersuchungen gemessen und verglichen.Ergebnisse:Die größten Seedverschiebungen nach kaudal fanden sich an der Basis: durchschnittlich 5,3 mm (B), 2,2 mm (A), 2,7 mm (U), 3,3 mm (R; p < 0,001). Dorsale Verschiebungen herrschten sowohl an der Basis als auch in der Zentralregion vor: durchschnittlich 2,2 mm (B), 2,0 mm (U), 0,8 mm (A), –0,6 mm (R; p < 0,001). Mit abnehmendem Ödem zwischen Tag 1 und 30 (durchschnittliches Prostatavolumen von 51 cm3 vs. 41 cm3; p < 0,001) verschob sich die Basis um durchschnittlich 3,9 mm nach kaudal. Die mittlere Einwärtsverschiebung der übrigen Ränder lag hingegen bei 1,2–1,6 mm (lateral, ventral, dorsal, apikal). Die Untersuchung der Strandlängen zeigte eine Stauchung des Implantats zwischen Tag 1 und 30 (durchschnittlich 1,7 mm; p < 0,001).Schlussfolgerung:Die größten Prostataoberflächen- und Seedverschiebungen fanden sich an der Prostatabasis, assoziiert mit einer Stauchung des Implantats. Die vorwiegend kaudalen und dorsalen Verschiebungen implizieren als Konsequenz kleinere Sicherheitsabstände am Apex und am dorsalen Prostatarand.

Rectal dosimetry following prostate brachytherapy with stranded seeds – Comparison of transrectal ultrasound intra-operative planning (day 0) and computed tomography-postplanning (day 1 vs. day 30) with special focus on sources placed close to the rectal wall

BACKGROUND AND PURPOSE The aim of the study was to compare intra-operative and postplanning at different intervals with special focus on sources placed close to the rectal wall. MATERIALS AND METHODS In 61 consecutive patients, CT scans were performed on day 1 and day 30 after an I-125 implant with stranded seeds. The number of sources < or =7 mm to the rectal wall was determined, and displacements were analyzed. The angulation of strands relative to rectal wall was compared between intra-operative transrectal ultrasound (TRUS) and both postplanning CT scans. RESULTS Sources close to the rectum on day 1 (n=204) have been the most apical in a strand in 98.5% (n=201). By comparing day 1 and day 30 data, significant inferior source displacements (mean 3.6 mm; p=0.02) relative to pelvic bones and a decreasing distance to the rectal wall (mean 1.2 mm; p<0.01)--consequentially increasing rectal dose--were determined only for sources initially > or =3 mm to the rectum. In contrast to an almost parallel arrangement of the needle track and the rectal wall in TRUS, strands and rectal wall converged towards the apex in the postplanning CT scans (mean >30 degrees). CONCLUSIONS Posterior preplanning margins around the prostate should be particularly limited at the level of the prostate apex.

Die erweiterte, radikale perineale Prostatektomie

Zusammenfassung125 konsekutive Patienten mit Adenokarzinom der Prostata wurden einer erweiterten radikalen perinealen Prostatektomie entsprechend der Technik von Weldon unterzogen. Diese Technik wurde durch die primäre komplette Mobilisation der Prostatahinterfläche und der Samenblasen, der Inzision der Faszia endopelvina, der queren Inzision der Denonvillier-Faszia am Apex und der partiellen Durchtrennung des dorsalen Venenkomplexes nach vorangegangener Durchstechungsligatur modifiziert.Die perioperative Morbidität war gering. Eine operative Wundrevision war bei 4 (3,2%) der Patienten wegen subkutaner arterieller Blutung aus dem Drainagekanal (n=1), Wundinfekt (n=2) und rektokutaner Fistel (n=1) erforderlich. Der Dauerkatheter wurde bei 104 (83%) Patienten am 4.–8. Tag entfernt. Positive Schnittränder fanden sich nur bei 22 (17,6%) Patienten. Es handelte sich dabei um 17 pT3- und 5 pT4-Tumoren mit Gleason-Score ≥7 (n=17), ausgedehntem, multifokalem Kapseldurchbruch (n=18), Infiltration der Samenblasen (n=11) und Lymphknotenmetastasen (n=4). Die unifokal positiven Schnittränder fanden sich am Apex (n=3), dorsolateral (n=6) und am Blasenhals (n=4); 9-mal lag ein multifokal positiver Schnittrand vor.Die Wahrscheinlichkeit des positiven Schnittrandes ist abhängig vom Serum-PSA, Gleason-Score und Tumorvolumen. Wird auf eine Potenzerhaltung verzichtet, so wird zur Vermeidung von positiven Schnitträndern die erweiterte radikale perineale Prostatektomie mit den angegebenen Modifikationen empfohlen.AbstractOne hundred and twenty-five consecutive patients with prostate cancer underwent an extended, radical perineal prostatectomy according to the technique described by VE Weldon. This technique was modified by an initial complete mobilization of the posterior aspect of the prostate and seminal vesicles from the rectum and pelvic wall, incision of the endopelvic fascia, and partial resection of the dorsal vein complex after suture ligature. The perioperative morbidity was low.An operative revision was necessary in four (3.2%) patients because of arterial bleeding from a drainage channel (n=1), wound infection (n=2), and rectocutaneous fistula (n=1). The in-dwelling catheter was removed on day 4–8 in 104 (83%) patients. Positive surgical margins were diagnosed in 22 (17.6%) patients only. These patients had pT3 (n=17) and pT4 (n=5) tumors with a Gleason score ≥7 (n=17) mostly; extensive, multifocal capsular penetration (n=18); seminal vesicle invasion (n=11); and lymph node metastases (n=4). The unifocal positive margins were localized at the apex (n=3), dorsolateral (n=6) aspect, and bladder nech (n=4). In nine patients, multifocal positive surgical margins were noted.The risk for a positive surgical margin depends on the serum PSA level, Gleason score, and tumor volume. In case potency prservation is not considered, the extended, radical perineal prostatectomy with the above mentioned modifications should be considered to guarantee a low rate of surgical margins.

Radical Prostatectomy in Patients with Previous Groin Hernia Repair Using Synthetic Nonabsorbable Mesh

Objective: Identification of patients in whom the perineal route is the optimal approach to perform radical prostatectomy. Material and Methods: During 1992–1999, 376 patients with prostate cancer underwent radical perineal prostatectomy. Four patients were identified in whom the perineal approach was indicated because of previous bilateral groin hernia repair using synthetic meshes. In addition, 1 patient underwent perineal prostatectomy elsewhere for similar reasons. Results: The perineal approach offered an uneventful surgical solution for an adequate and straightforward radical perineal prostatectomy without complications and without biochemical recurrence during the follow-up. Conclusion: Radical perineal prostatectomy is suggested to be the optimal approach in patients with previous bilateral groin hernia repair using synthetic, nonabsorbable meshes.

Inverse Automated Treatment Planning with and without Individual Optimization in Interstitial Permanent Prostate Brachytherapy with High- and Low-Activity 125I

Purpose: To determine whether dose distribution achieved with treatment plans using high- and low-activity 125I implants differs. Patients and Methods: Based on intraoperative transrectal ultrasound scans of 71 patients, inverse automated treatment plans (IATP) were performed with 15.5-kBq (0.42-mCi) and 25.2-kBq (0.68-mCi) 125I implants using a commercial 3-D planning system (Variseed®). A prescription dose of 145 Gy in 98% of the prostate volume (V100), a maximum dose to the urethra of 250 Gy (D1), and a maximum dose to 10% of the anterior rectal wall of 145 Gy (D10) were required. The plans were manually corrected, if necessary. Results: In the IATP, a better dose coverage of the prostate was found for high-activity seeds (V100 of 98% vs 84%). The prostate dose values increased with the prostate volume. After manual optimization, the differences were only marginal with a prostate V100 of 99% for both activities, a urethra D1 of 247 Gy and 239 Gy, and a rectum D10 of 135 Gy and 124 Gy for high- and low-activity seeds. Low-activity seeds required more sources (66 vs 47) and needles (24 vs 17; all numbers are median values). Conclusions: Concerning the prostate dose coverage, high-activity seeds are superior in the IATP. After manual adjustment, the dose values for the prostate and the organs at risk are similar. Considering a supposedly decreased toxicity and a shorter implantation time for a lower number of seeds, we recommend high-activity seeds for experienced teams.Fragestellung: Erzielt die Bestrahlungsplanung sowohl mit hoch- als auch mit niedrigaktiven 125J-Seeds eine optimale Dosisverteilung? Patienten und Methodik: Basierend auf intraoperativen transrektalen Ultraschallbildern von 71 Patienten erfolgte eine inverse automatische Bestrahlungsplanung (IATP) unter Verwendung von 15,5-kBq-(0,42-mCi-) und 25,2-kBq-(0,68-mCi-)-125J-Seeds mit einem kommerziellen 3-D-Planungssystem (Variseed®). Eine Verschreibungsdosis von 145 Gy in 98% des Prostatavolumens (V100), eine maximale Dosis im Bereich der Urethra von 250 Gy (D1) und maximal 10% der Rektumvorderwand im Bereich der 145-Gy-Isodose (D10) wurden gefordert. Die Pläne wurden bei Notwendigkeit manuell verbessert. Ergebnisse: Im IATP wurde eine bessere Dosis für die Prostata bei hochaktiven Seeds erreicht (V100 von 98% vs. 84%). Die Dosiswerte für die Prostata stiegen mit zunehmendem Prostatavolumen. Nach manueller Optimierung waren die Unterschiede nur marginal (Prostata V100 von 99% für beide Aktivitäten, Urethra D1 von 247 Gy und 239 Gy und Rektum D10 von 135 Gy und 124 Gy für hohe und niedrige Aktivitäten). Bei Anwendung der niedrigen Aktivität wurden mehr Seeds (66 vs. 47) und Nadeln (24 vs. 17) benötigt (alle Zahlen sind Medianwerte). Schlussfolgerungen: Unter Verwendung der IATP zeigen sich die hochaktiven Seeds bezüglich der Prostatadosis überlegen. Nach manueller Korrektur sind die Dosiswerte für die Prostata und die Risikoorgane ähnlich. Berücksichtigt man die anzunehmende geringere Toxizität und kürzere Implantationsdauer für eine kleinere Anzahl von Seeds, so sind hochaktive Seeds für erfahrene Teams zu empfehlen.