AimIntensity‐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).MethodsSixteen 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.ResultsEleven 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).ConclusionsBoth 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.
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