Dosimetric Comparison of Static Field Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Adjuvant Treatment of Patients with Endometrial Cancer

İngilizce (OpenAlex)

The extent of previously published studies comparing static intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in the adjuvant setting of endometrial cancer is limited and reports do not cover the whole landscape of today's clinical practice.The aim of this study was to compare these treatment techniques. METHODSUsing 12 image sets, VMAT with double arcs and IMRT with 7 fields were planned.The femoral heads, rectum, bladder, iliac bone marrow, and bowels were contoured as organs at risk (OARs).Planned treatment volume (PTV) was prescribed to be 45 gray (Gy).Target and OAR parameters, conformity, and homogeneity indices were evaluated.P value under 0.05 was considered statistically significant. RESULTSObjectives for target volumes were achieved.No significant differences were found in conformity index, maximum dose (D max ), or integral dose.Homogeneity index was better with IMRT (1.06 vs. 1.07; p<0.01).Dose received by 2% volume of PTV (D 2% ), D 5% , the volume receiving 107% of prescribed dose (V 107% ), and V 105% were lower with IMRT (p<0.05).PTV D 98% , percent volume receiving ≥45 Gy (V 45 Gy ), and clinical target volume V 45 Gy were higher with VMAT (p<0.05).Regarding OARs, only rectum V 40 Gy , rectum PTV V 40 Gy , and dose volume parameter D 2cc were lower with VMAT (p<0.05).VMAT was superior with respect to monitor units and beam-on time per fraction: 465 vs. 1689 and 166 vs. 338 seconds, respectively (p<0.001). CONCLUSIONStatic IMRT is superior to VMAT regarding homogeneity, Dmax and OAR sparing, except for the rectum and the bladder.However, it is a marginal benefit with small differences.VMAT remains an attractive solution due to low number of monitor units needed and shorter treatment duration, which allows more time for patient imaging and positioning.