Radiotherapy for Esophageal Cancer Using Simultaneous Integrated Boost Techniques: Dosimetric Comparison of Helical TomoTherapy, Volumetric-Modulated Arc Therapy (RapidArc) and Dynamic Intensity-Modulated Radiotherapy

Abstract

This study compared TomoTherapy (TM), with Volumetric-Modulated Arc Therapy (RapidArc, RA), and dynamic intensity-modulated radiotherapy (dIMRT) for locally advanced esophageal cancer (LAEC) with a simultaneous integrated boost (SIB) technique with regard to the target coverage and sparing of organs at risk (OARs). Twelve patients receiving fourdimensional computed tomography simulation were enrolled for dosimetric comparison.Gross tumor volume was contoured with the maximum intensity projection method. Using an SIB method, Planning target volume low (PTVL) and planning target volume high (PTVH) were prescribed as 54 Gy and 60 Gy, respectively, each administered in 30 fractions. We compared the results of statistical analysis for target coverage, homogeneity index (HI) and conformity index (CI) of PTVs, parameters of OARs and monitor unit (MU) were compared for analysis. The HI for PTVH varied significantly for the 3 techniques of TM, RA, and dIMRT (4.38 6 0.86, 6.40 6 0.86, and 6.11 6 0.68, respectively; P , 0.001). The CI scores for PTVH also differed across TM, RA, and dIMRT (0.64 6 0.06, 0.53 6 0.06, and 0.59 6 0.05, respectively; P , 0.001). The HI for PTVL showed a significant difference among TM, RA, and dIMRT (15.44 6 0.88, 20.88 6 1.03 and 18.65 6 1.42, respectively; P , 0.001). The percentage of lung volume receiving 5 Gy (V5) and 20 Gy (V20) (for V5: TM 54.4 6 8.0%; RA 67.5 6 14.5%, P , 0.01; dIMRT 44.8 6 8.2%; for V20: 13.6 6 3.3%, 12.2 6 3.6%, 18.1 6 3.4%, P 5 0.001, respectively). For RA, the lung V5 ≥ 65% was observed in 6 patients and the V10 ≥ 50 % in one patient. TM, RA and dIMRT provided comparable coverage of the target and sparing of OARs. TM demonstrated superior CI and HI for tumor coverage and lowered the specified dose parameters for lung. RA provided an advantage in terms of the lowest MU and V20 of the lung, but its higher lung V5 was of some concern about lung toxicity.

A broad scope knowledge based model for optimization of VMAT in esophageal cancer: validation and assessment of plan quality among different treatment centers

“…Volumetric modulated arc therapy (VMAT) has been investigated for esophageal cancer in a limited number of planning studies [ 11 – 18 ], and clinical results are still to be provided. From these investigations, VMAT resulted technically feasible with superior results in terms of dose distributions (target coverage and organs at risk (OAR) sparing) compared to 3D conformal therapy and also to fixed field intensity modulated therapy (IMRT).…”

Dosimetric comparison of TomoDirect, helical tomotherapy, VMAT, and ff-IMRT for upper thoracic esophageal carcinoma

“…12 Nguyen et al 13 also reported that compared to conventional 3D conformal RT, image-guided RT-based helical tomotherapy may achieve significant reduction of radiation dose to the lungs, cardiac ventricles, and spinal cord while delivering a higher dose to the gross target volume. A dosimetric comparison among different IMRT techniques has already been published in several series of studies; Wang et al 14 reported that tomotherapy demonstrated superior CI and HI for tumor coverage and lowered the specified dose parameters for lung; they also presented the clinical findings that using Varian patented IMRT arc therapy technique RapidArc (RA) has shown an advantage in terms of the lowest MU and V 20 of the lung. However, this article indicated higher lung V 5 value was of some concern of possible lung toxicity in dealing with EC delivery when compared to static beam techniques.…”

Impact of treatment planning using a structure block function on the target and organ doses related to patient movement in cervical esophageal cancer: A phantom study

“…Helical tomotherapy (HT) is a dose delivery technique, in which the treatment couch moves in the direction of the gantry rotation axis, and the high‐speed driving of 64 multileaf collimators allow the fluence to be finely modulated . Studies have shown that HT and volume‐modulated arc radiotherapy help improve the dose concentration at the target for cervical esophageal cancers . However, their use may increase the risk of radiation pneumonitis and pulmonary complications compared to using three‐dimensional (3D) conformal radiation therapy or intensity modulated radiotherapy, because of the increased low‐dose area in the lung .…”