Intensity‐modulated radiotherapy with an integrated boost to the macroscopic tumor volume in the treatment of high‐grade gliomas

Abstract

SUMMARY Integrated boost radiotherapy (IBRT) delivers a higher fraction size to the gross tumor volume and a conventional fraction size to the surrounding tissue of microscopic spread. We compared stereotactic conformal radiotherapy (SCRT) and intensitymodulated radiotherapy (IMRT) with regard to their suitability for IBRT in the treatment of high-grade gliomas. In 20 patients treated with conventional radiotherapy, an additional treatment plan for IBRT [planning target volume (PTV1) defined as contrast-enhancing lesion plus margin due to setup errors 75 Gy, PTV2 defined as edema plus margin due to microscopic spread and setup error 60 Gy] with 7 non-coplanar beams for IMRT and for SCRT was carried out and compared. The part of the PTV2 irradiated with more than 107% of the prescribed dose was 13.9% for IMRT and 30.9% for SCRT (P < 0.001). Dose coverage of PTV2 (volume above 95% of the prescribed dose) was improved with IMRT (88.4% vs. 75.3% with SCRT, P < 0.001). Dose coverage of PTV1 was slightly higher with SCRT (93.7% vs. 87.5% with IMRT), but the conformity to the boost shape was improved by IMRT [conformity index (COIN95) = 0.85 vs. 0.69 with SCRT]. Simultaneously the brain volume irradiated with > 50 Gy was reduced from 60 to 33 cc (P < 0.001). We conclude that IMRT is suitable for local dose escalation in the enhancing lesion and for delivering a homogeneous dose to the PTV2 outside the PTV1 at the same time. Our encouraging results justify application of IMRT for IBRT in the treatment of high-grade gliomas. For clinical evaluation a phase III study has been initiated.

Stereotactic Intensity-Modulated Radiation Therapy (IMRT) and Inverse Treatment Planning for Advanced Pleural Mesothelioma

“…Stereotactic inversely planned IMRT could be interesting especially for patients with favorable prognostic factors such as IMIG stages I and II, age < 50 years, female sex, and epithelial type [11]. One possible study protocol might be an integrated IMRT boost concept [32] with the treatment of the whole ipsilateral pleural space applying a higher daily dose to the grossly visible tumor in the same fraction.…”

Local High-Dose Radiotherapy and Sparing of Normal Tissue Using Intensity-Modulated Radiotherapy (IMRT) for Mucosal Melanoma of the Nasal Cavity and Paranasal Sinuses

“…The KonRad software developed at the German Cancer Research Center (dkfz) was used for IMRT treatment planning [35,63]. The simultaneous treatment of different target volumes, here defined as GTV and CTV, with different daily fraction sizes was performed.…”

Intensit�tsmodulierte Bestrahlung (IMRT) von Kopf-Hals-Tumoren

“…"integrierten Boosts" verabreichen. Gegenüber einer konventionellen, nachgeschalteten Boostbestrahlung hat dieses Konzept den Vorteil, dass aufgrund der höheren Einzelfraktionsgrö-ßen gegenüber einer konventionellen Bestrahlung selbst bei nominell gleicher Gesamtdosis die biologische Wirksamkeit besser sein dürfte [1,30].…”