Dosimetric comparison of volumetric-arc therapy versus sliding window intensity-modulated radiotherapy in postoperative treatment for primary soft tissue sarcoma of the thigh.

Autor: Ortiz González I; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Morera Cano D; Medical Physics Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Roncero Sánchez R; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Mateos Salvador P; Medical Physics Department, Clinica IMQ Zorrotzaurre, Bilbao, Spain., Valencia Blanco L; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Vidal Borrás M; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Aymar Salís N; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Gadea Quinteiro J; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Jiménez Jiménez E; Radiation Oncology Department, Complejo Hospitalario Universitario de Albacete, Albacete, Spain., Gelabert JF; Medical Physics Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain., Pardo Masferrer J; Radiation Oncology Department, Hospital Universitari Son Espases, Palma de Mallorca, Spain.; Institut d'Investigació Sanitaria de Illes Balears, Palma de Mallorca, Spain.; Hospital General de Catalunya Quironsalud, Sant Cugat del Vallès, Spain.
Jazyk: angličtina
Zdroj: Asia-Pacific journal of clinical oncology [Asia Pac J Clin Oncol] 2019 Dec; Vol. 15 (6), pp. 371-376. Date of Electronic Publication: 2019 Jul 18.
DOI: 10.1111/ajco.13220
Abstrakt: Aim: Intensity-modulated radiotherapy (IMRT) has demonstrated improved local control in extremity soft tissue sarcoma (STS) after limb-sparing surgery compared with three-dimensional conformal radiation therapy. Our purpose was to evaluate sliding-window IMRT (SW-IMRT) and volumetric arc therapy (VMAT) in planning target volume (PTV) coverage and dose to organs-at-risk (OAR).
Methods: Sixteen patients undergoing postoperative RT for lower extremity STS were included. For each patient, one VMAT plan and one SW-IMRT plan were proposed. Both were evaluated using cumulative dose-volume histogram data for OAR and PTVs. Prescribed dose was 66 Gy (2 Gy/fraction) to PTV1 and 56 Gy (1.69 Gy/fraction) to PTV2. OARs contoured were femur, neurovascular bundle, minimum tissue corridor, normal tissue outside PTV2, joint and genitalia. T-Student test was performed.
Results: Eleven male (69%) and five female patients (31%) were analyzed. Mean age was 60 years. Both techniques showed optimal target coverage, conformity index (CI) and homogeneity index (HI). VMAT PTV2 CI was 1.13 (mean) ± 0.08 (standard deviation) versus 1.19 ± 0.10 SW-IMRT PTV2 CI (P < 0.05). VMAT PTV1 HI was 0.09 ± 0.01 versus 0.08 ± 0.01 SW-IMRT PTV1 HI (P < 0.05). Regarding OARs, VMAT delivered lower dose to femur, genitalia, normal tissue outside PTV2 and joints. SW-IMRT spared tissue corridor mean dose (10.4 Gy ± 6.8 Gy) versus (14.7 ± 6.5 Gy) VMAT (P < 0.05).
Conclusions: Both techniques achieved great conformity, homogeneity and coverage of PTV. VMAT produced lower dose to OARS and SW-IMRT was superior in sparing dose to normal-tissue-corridor, which could reduce risk of lymphedema.
(© 2019 John Wiley & Sons Australia, Ltd.)
Databáze: MEDLINE
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