Nathalie Arians

Radiochemotherapie verbessert „failure-free survival“ beim Endometriumkarzinom im Stadium III

Patienten und Methode. Von 2006 bis 2013 wurden für die prospektive, randomisierte Phase-III-Studie PORTEC-3 686 Patientinnen mit Endometriumkarzinom nach makroskopisch kompletter Resektion rekrutiert. In die Studie eingeschlossen wurden Patientinnen mit endometrioider Histologie im Stadium FIGO I G3 (wenn gleichzeitig >50% Mymometriuminfiltration und/oder eine lymphovaskuläre Invasion vorlag) oder im Stadium FIGO II–III sowie Patientinnen mit seröser oder klarzelliger Histologie im Stadium FIGO I–III. Randomisiert wurden die Patientinnen auf die alleinige adjuvante perkutane Bestrahlung mit 48,6Gy oder die Kombinationstherapie aus Radiotherapie mit 2 simultanen Gaben von Cisplatin 50mg/m2 und anschließend 4 weiteren Gaben von Carboplatin/Paclitaxel. Etwa 45% der Patientinnen erhielten einen endovaginalen Brachytherapie-Boost. Primäre Endpunkte waren das Gesamtüberle-

Treatment planning for MLC based robotic radiosurgery for brain metastases: plan comparison with circular fields and suggestions for planning strategies

Abstract To evaluate the possible range of application of the new InCise2 MLC for the CyberKnife M6 system in brain radiosurgery, a plan comparison was made for 10 brain metastases sized between 1.5 and 9cm3 in 10 patients treated in a single fraction each. The target volumes consist of a PTV derived by expanding the GTV by 1mm and were chosen to have diversity in the cohort regarding regularity of shape, location and the structures needed to be blocked for beam transmission in the vicinity. For each case, two treatment plans were optimized: one using the MLC and one using the IRIS-collimator providing variable circular fields. Plan re-quirements were: dose prescription to the 70% isodose line (18 or 20Gy), 100% GTV coverage, ≥98% PTV coverage, undisturbed central high dose region (95% of maximum dose) and a conformity index as low as possible. Plan com-parison parameters were: conformity index (CI), high-dose gradient index (GIH), low-dose gradient index (GIL), total number of monitor units (MU) and expected treatment time (TT). For all cases, clinically acceptable plans could be gen-erated with the following results (mean±SD) for CI, GIH, GIL, MU and TT, respectively for the MLC plans: 1.09±0.03, 2.77±0.26, 2.61±0.08, 4514±830MU and 27±5min and for the IRIS plans: 1.05±0.01, 3.00±0.35, 2.46±0.08, 8557±1335MU and 42±7min. In summary, the MLC plans were on average less conformal and had a shallower dose gradient in the low dose region, but a steeper dose gradient in the high dose region. This is accompanied by a smaller vol-ume receiving 10Gy. A plan by plan comparison shows that usage of the MLC can spare about one half of the MUs and one third of treatment time. From these experiences and results suggestions for MLC planning strategy can be de-duced.