25 Oesophageal Cancer

Oesophageal Cancer Brachytherapy

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THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 10/06/2019

of the oesophageal wall is measured. This thickness can be derived from the endoluminal ultrasonography or from the planning CT or MRI in 3D planning. The thickness of the wall is dependent on tumour thickness and the filling condition. Without thickening by tumour infiltration, the wall measures under physiologic resting conditions about 1.87-4.95 mm (Xia et al. 2009). In order to eliminate localization uncertainties and geographic mismatch it is important to implant radiopaque markers (e.g. clips or contrast media) at the cranial and caudal edges of the CTV (GTV plus 1 cm safety margins cranially and caudally) into the oesophageal wall during the oesophagoscopy and document by fluoroscopy and digital radiographs. The oesophagoscopy is best performed with the specialized gastro-enterologist and will also be used to place the applicator for endoluminal brachytherapy. To allow for applicator location uncertainties (fig. 27.5) a PTV margin of 1 cm is defined at both longitudinal ends of the CTV (GTV to PTV total margin 2 cm).

7. A.2. Boost after external beam (chemo)radiotherapy The traditional target approach takes into account the extension and depth of the GTV at diagnosis and adds margins as appropriate for longitudinal and circumferential extension (eg. 1 cm). Another PTV margin of 1 cm may be added to account for applicator location uncertainties. The Adaptive Image Guided Brachytherapy concept as developed and already applied for IGABT in cervix [ICRU Report 89, Haie- Meder et al.], anal [Van Limbergen et al.], rectal [Dresen et al.], nasopharynx [Bacorro et al.], and vaginal cancer [Schmid et al.], is also applicable to curative intent oesophageal brachytherapy after initial chemoradiotherapy. High precision localisation with endoscopy and EUS and 3D planning on CT and MRI is in this setting mandatory as well. The residual tumour volume (GTV) and residual oedematous (grey) zones at the time of brachytherapy represent the high-risk clinical target volume (HR-CTV). However, it is also necessary to take into consideration the initial size of the gross tumour volume

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Fig. 27.4 D. large oesophageal tumour with stenosis, transmural growth and infiltration into adjacent organs (left main bronchus, pericardium, diaphragm, pleura): T4

Fig. 27.4 E. Barium Swallow.

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From fig 27.4 A to fig. 27.4 E. T-staging of oesophageal cancer (T1-T4) based on Computed Tomography and Barium swallow X-ray for brachytherapy treatment planning Courtesy to Ahmed Ba-Ssalamah and Sarah Pötter-Lang, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria