Feasibility of using intensity-modulated radiotherapy to improve lung sparing in treatment planning for distal esophageal cancer

Volumetric modulated arc therapy planning for distal oesophageal malignancies

“…The studied population mean V5 for VMATi is 51% (range 38-84%). This appears to be slightly lower than the values described by Mayo et al [14]: mean 56.5¡17% (for 4-field IMRT) and 67.4¡17% (for 9-field IMRT); and those described by Chandra et al [13]: median 58.6% (for 4-field IMRT) and 68.3% (for 9-field IMRT). Therefore, this technique appears to have V5 doses at a similar level to those demonstrated by IMRT.…”

“…There is no significant reduction with cARC plans for V40%. The same magnitude of reduction in cardiac doses has not been illustrated by other studies, such as Chandra et al [13], who found no significant change when attempting to reduce heart dose, whereas Mayo et al [14] described V30 of .55% for hybrid IMRT and conventional plans but did not specifically attempt to reduce heart dose. Helical tomotherapy has also been described to reduce the volume of heart irradiated in this tumour site [16].…”

“…Oesophageal IMRT studies have concentrated on lung dose reduction with improved target conformality [13][14][15]. In the current series we have attempted to keep the dose delivered low to all surrounding critical structures.…”

“…A few studies have investigated the potential dosimetric advantage of IMRT in oesophageal cancer [13][14][15][16][17] and have demonstrated better dose conformity to the planning target volume (PTV) and lower V20 and V30 lung volumes. One study that included in the planning goals an absolute reduction of 10% in volumes of heart receiving 40 Gy and 50 Gy described no significant reduction in cardiac dose compared with the clinical plan [13], but also indicated that in certain cases with better dose-volume histogram (DVH) objectives the heart dose could be reduced with IMRT. Sparing of the heart in terms of V30 or V45 is described with tomotherapy for oesophageal cancers [16].…”

“…The arc plans were compared with clinically optimised conformal four-field plans as a conformal four-field plan is the current standard practice both at this centre and elsewhere. IMRT techniques have been investigated previously [13][14][15][16][17], so are not considered here. The aim was to reduce heart and spinal cord dose, while maintaining lung receiving 20 Gy ,20% and PTV coverage by 95% prescription isodose.…”