Axel Schmachtenberg

Radiotherapy in the management of keloids. Clinical experience with electron beam irradiation and comparison with X-ray therapy.

Background: Aim of this study was to evaluate the advantages of electon beam irradiation compared to kilovoltage X-ray therapy in the treatment of keloids. Furthermore, the risk of developing malignancy following keloid radiotherapy was assessed. Patients and Methods: An automatic water phantom was used to evaluate the dose distribution in tissue. Furthermore, a series of measurements was done on the patients using thermoluminescence dosimeters (TLD) to estimate the doses absorbed by the organs at risk. We also report our clinical experience with electron beam radiation of 134 keloids following surgical excision. Results: Electron beam irradiation offers a high control rate (84%) with minimal side effects for keloids. Electron irradiation provides better doses distribution in tissue, and therefore less radiation burden to the organs at risk. After a mean follow-up period of 7.2 years, no severe side effects or malignancies were observed after keloid radiotherapy. Conclusions: Electron radiation therapy is superior to kilovoltage irradiation for treating keloids due to better dose distribution in tissue. In agreement with the literature, no cases of malignancy were observed after keloid irradiation.Hintergrund: Diese Arbeit befasst sich mit der Bestrahlungsmethodik und den Vorteilen einer Strahlentherapie mit Elektronen eines Linearbeschleunigers im Vergleich zur bisher üblichen Bestrahlung mit Röntgengeräten. Ferner wird auf das Risiko der Entwicklung von Malignomen nach Keloidbestrahlung eingegangen. Patientengut und Methode: An einem automatisch registrierenden Wasserphantom wurden vergleichend die Tiefendosisverläufe im Gewebe untersucht. Wir führten außerdem eine Serie von Messungen an Patienten mit einem Thermolumineszenzdosimeter durch, um die Dosisbelastung strahlensensibler Organe einzuschätzen. Zudem präsentieren wir unsere Ergebnisse der Behandlung von 134 Keloiden mit Elektronen eines Linearbeschleunigers. Ergebnisse: In unserem Patientenkollektiv lag die Rezidivfreiheit bei 84% bei minimalen strahleninduzierten Nebenwirkungen. Elektronenbestrahlung führt zu einer günstigeren Dosisverteilung im Gewebe und dadurch zu einer niedrigeren Dosisbelastung strahlensensibler Organe. Nach einer mittleren Nachbeobachtungszeit von 7,2 Jahren sind keine hochgradigen Nebenwirkungen oder Malignome festgestellt worden. Schlussfolgerungen: Postoperative Keloidbestrahlung mit Elektronen eines Linearbeschleunigers ist wegen der besseren Dosisverteilung im Gewebe der Bestrahlung mit konventionellen Röntgengeräten vorzuziehen. In Übereinstimmung mit der Literatur sind in unserem Patientenkollektiv keine Malignome beobachtet worden.

Gemcitabine concurrent with thoracic radiotherapy after induction chemotherapy with gemcitabine/vinorelbine in locally advanced non-small cell lung cancer: a phase I study.

Purpose:To determine the maximum tolerated dose (MTD) of gemcitabine every 2 weeks to a concurrent radiotherapy administered during an aggressive program of sequential and simultaneous radio-/chemotherapy for locally advanced, unresectable non-small cell lung cancer (NSCLC).Patients and Methods:Ten patients with histologically confirmed NSCLC were observed and treated in accordance with a combined radio-/chemotherapy protocol. This included two cycles of induction chemotherapy with gemcitabine (1,200 mg/m2) and vinorelbine (30 mg/m2) at days 1, 8 and 22, 29, followed by concurrent radiotherapy including [18F] fluorodeoxyglucose positron emission tomography-(FDG-PET-)based target volume definition (2.0 Gy/d; total dose 66.0 Gy) and chemotherapy with gemcitabine every 2 weeks at days 43, 57, and 71. The initial dose was 300 mg/m2. The dose of gemcitabine was increased by 100 mg/m2 until the MTD was realized. Three patients were enrolled for each dose level.Results:Dose-limiting toxicity (DLT) was identified for the patient group receiving gemcitabine 500 mg/m2, due to grade 2 esophagitis (next to grade 3) in all patients. 6 weeks after the completion of radio-/chemotherapy, most patients still presented treatment-induced esophagitis. In accordance with expected complications, such as esophagitis, dysphagia and odynophagia, the MTD was defined at this dose level, although no DLT grade 3 was reached.Conclusion:After induction chemotherapy, the MTD and frequency of gemcitabine in locally advanced NSCLC is 500 mg/m2 every 2 weeks during a maximum of 7 weeks of thoracic radiotherapy.Ziel:Festlegung der maximal tolerablen Dosis (MTD) von Gemcitabin, verabreicht im 14-tägigen Intervall parallel zur perkutanen Radiotherapie, appliziert während einer dosisdichten Therapie, bestehend aus sequentieller und simultaner Radio-/Chemotherapie, bei lokal fortgeschrittenem, inoperablem nichtkleinzelligen Bronchialkarzinom (NSCLC).Patienten und Methodik:Zehn Patienten mit histologisch gesichertem NSCLC wurden gemäß Studienprotokoll mit kombinierter Radio-/Chemotherapie behandelt. Dieses beinhaltete zwei Zyklen Induktionschemotherapie mit Gemcitabin (1 200 mg/m2) und Vinorelbin (30 mg/m2) an Tag 1, 8 sowie 22, 29, gefolgt von einer simultanen Radio-/Chemotherapie mit Gemcitabin im 2-wöchigen Abstand, an den Tagen 43, 57 und 71. Die initiale Gemcitabin-Dosis betrug 300 mg/m2. Die Dosis wurde in 100-mg/m2-Schritten bis zum Erreichen der MTD gesteigert. In jeder Dosisstufe wurden drei Patienten aufgenommen. Parallel dazu wurde eine Radiotherapie mit [18F]-Fluorodeoxyglucose-Positronenemissionstomographie-(FDG-PET-)basierter Zielvolumendefinition (2,0 Gy/d; Gesamtdosis 66,0 Gy) durchgeführt.Ergebnisse:Die dosislimitierende Toxizität (DLT) wurde bei der Gabe von 500 mg/m2 erreicht. In dieser Dosisstufe zeigte sich bei allen Patienten eine Grad-2-Ösophagitis (unmittelbar am Übergang in eine Grad-3-Ösophagitis). Des Weiteren zeigten sich bei der ersten Nachsorge ca. 6 Wochen nach Abschluss der Behandlung weiterhin entzündliche Veränderungen der Speiseröhre. Aufgrund der zu erwartenden Komplikationen wie einer Ösophagitis Grad 3–4, Dysphagie und Odynophagie wurde die MTD bei dieser Dosisstufe definiert, obwohl keine DLT Grad 3 erreicht wurde.Schlussfolgerung:Nach Induktionschemotherapie lagen die MTD und Frequenz von Gemcitabin bei 500 mg/m2 im 14-tägigen Intervall parallel zur Radiotherapie.

Dose-volume histogram evaluation of prone and supine patient position in external beam radiotherapy for cervical and endometrial cancer

BACKGROUND AND PURPOSE To evaluate the influence of patient positioning on dose-volume histograms of organs at risk in external beam radiotherapy for cervical and endometrial cancer. MATERIALS AND METHODS In 20 patients scheduled for definitive (7) or postoperative (13) external beam radiotherapy of the pelvis treatment planning CT scans were performed in supine and prone (belly board) positions. After volume definition of target and organs at risk treatment plans were calculated applying the four-field box technique. The dose-volume histograms of organs at risk were compared. RESULTS Radiotherapy in prone position causes a reduction of the bladder portion (mean 15%, p<0.001) and an increase of the rectum portion (mean 11%, p<0.001) within the 90% isodose. A reduction of the bowel portion could only be observed in postoperatively treated patients (mean 13%, p<0.001). In definitive radiotherapy the target volume increases in supine position (mean 7%, p=0.02) due to an anterior tumour/uterus movement, so that bowel portions within the 90% isodose are similar. The bladder filling correlates with a reduction of bladder and bowel (postoperatively treated patients) dose. CONCLUSIONS External beam radiotherapy of the pelvis should be performed in prone position in postoperative patients because of best bowel protection. Considering the additional HDR brachytherapy rectum protection takes the highest priority in definitive treatment-the requirements are best met in supine position. An adequate bladder filling is important to reduce the irradiated bladder and bowel volumes.

Sequential (gemcitabine/vinorelbine) and concurrent (gemcitabine) radiochemotherapy with FDG-PET-based target volume definition in locally advanced non-small cell lung cancer: first results of a phase I/II study

BackgroundThe aim of the study was to determine the maximal tolerated dose (MTD) of gemcitabine every two weeks concurrent to radiotherapy, administered during an aggressive program of sequential and simultaneous radiochemotherapy for locally advanced, unresectable non-small cell lung cancer (NSCLC) and to evaluate the efficacy of this regime in a phase II study.Methods33 patients with histologically confirmed NSCLC were enrolled in a combined radiochemotherapy protocol. 29 patients were assessable for evaluation of toxicity and tumor response. Treatment included two cycles of induction chemotherapy with gemcitabine (1200 mg/m2) and vinorelbine (30 mg/m2) at day 1, 8 and 22, 29 followed by concurrent radiotherapy (2.0 Gy/d; total dose 66.0 Gy) and chemotherapy with gemcitabine every two weeks at day 43, 57 and 71. Radiotherapy planning included [18F] fluorodeoxyglucose positron emission tomography (FDG PET) based target volume definition. 10 patients were included in the phase I study with an initial gemcitabine dose of 300 mg/m2. The dose of gemcitabine was increased in steps of 100 mg/m2 until the MTD was realized.ResultsMTD was defined for the patient group receiving gemcitabine 500 mg/m2 due to grade 2 (next to grade 3) esophagitis in all patients resulting in a mean body weight loss of 5 kg (SD = 1.4 kg), representing 8% of the initial weight. These patients showed persisting dysphagia 3 to 4 weeks after completing radiotherapy. In accordance with expected complications as esophagitis, dysphagia and odynophagia, we defined the MTD at this dose level, although no dose limiting toxicity (DLT) grade 3 was reached.In the phase I/II median follow-up was 15.7 months (4.1 to 42.6 months). The overall response rate after completion of therapy was 64%. The median overall survival was 19.9 (95% CI: [10.1; 29.7]) months for all eligible patients. The median disease-free survival for all patients was 8.7 (95% CI: [2.7; 14.6]) months.ConclusionAfter induction chemotherapy, the maximum tolerated dose and frequency of gemcitabine was defined at 500 mg/m2 every two weeks in three cycles during a maximum of 7 weeks of thoracic radiotherapy for the phase II study. This regimen represents an effective and tolerable therapy in the treatment of NSCLC.

Innovationen in der Tumortherapie

Innovationen und der Einsatz neuer Techniken beeinflussen das medizinische Fachgebiet der Radioonkologie erheblich; sie ermoglichen heute eine Tumortherapie mit groserer Effektivitat. Weil die Bestrahlung zunehmend individueller geplant werden kann, ist der therapeutische Gewinn — sei es mit schmerzlindernder oder kurativer Intention — erhoht; die Exposition des gesunden Gewebes wahrend einer Tumorbehandlung last sich gleichzeitig auf das notwendige Minimum reduzieren, so das die Lebensqualitat der Patienten kaum beeintrachtigt wird.