25 Oesophageal Cancer

Oesophageal Cancer Brachytherapy

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

6.B. Curative indications in inoperable OC (cT2-3 cN0-3 cM0) – boost procedure In these indications, as most oesophageal tumours are large at diagnosis (T3/4, stage III/IV, extensive disease), endoluminal brachytherapy alone is not sufficient to achieve complete tumour remission, especially for disease deep in the oesophageal wall and plexus (cT2-3). The combination of external radiotherapy (with or without chemotherapy) and endoluminal brachytherapy is therefore the recommended treatment, starting with external beam radiotherapy combined with chemotherapy in order to induce tumour remission and adding brachytherapy as a boost treatment to a reduced volume.This strategy can follow the response adaptive target approach which was first introduced in cervical cancer with definition of initial and residual GTV and based on this to define the intermediate-risk and high-risk CTVs (CTV IR and CTVHR) (see section 7 on target volume). In selected cases, brachytherapy may be used at the start of radiotherapy to achieve rapid symptom relief from advanced oesophageal stenosis and bleeding, if the cancer lesions are passable by the endoscope and the endoluminal brachytherapy applicator can be safely introduced prior to the downsizing effect of external beam radiotherapy.The use of oesophageal stenting - as an alternative to brachytherapy - in patients with cancer-related dysphagia undergoing combined chemotherapy and external beam radiotherapy (CRT) with curative intent is associated with a significant increase of grade 3 and higher toxicity (71%versus 27%, p<0.01) and inferior survival (p=0.026) and therefore cannot be recommended [Francis et al.]. Finally, endoluminal brachytherapy may also be added if not initially planned, when tumour remission achieved by external radiotherapy has not been sufficient, to increase the local effect in curative situations. In stage I-IIIA tumours - in particular in tumours which are inoperable for technical reasons (cervical oesophagus, upper third of thoracic oesophagus) or medical reasons - a combined treatment using external radiotherapy and HDR-brachytherapy with curative intent is indicated. Endoluminal brachytherapy as a boost procedure was introduced in the late 1980s and proved feasible in phase II trials [Calais et al.]. In randomized controlled trials endoluminal brachytherapy boost has been tested against external beam boost after chemoradiation and proved superior in patients with tumour length <5 cm [Okawa et al.]. This study by Okawa et al. of the Japanese Society of Therapeutic Radiology andOncology (JASTRO) also demonstrated the feasibility of HDR or LDR brachytherapy with two fractions of 5 Gy as a once-weekly procedure after 60 Gy of external beam irradiation (EBRT). Cancer specific survival was improved in lesions smaller than 5 cm in patients receiving a brachytherapy boost [Okawa et al.] (see table 27.1). However, the continuation of chemotherapy (combination of cisplatin and 5-fluorouracil) during the brachytherapy boost phase after 50 Gy chemoradiotherapy and the use of higher brachytherapy boost doses of 15-20 Gy may be very toxic with life-threatening toxicity [Gaspar et al.]. 6.C. Curative indications in operableOC (cT2-3 cN+ cM0) – boost procedure Since alleviating dysphagia is important to maintain nutritional status [Homs et al., Amdal et al., Bergquist et al.] endoluminal brachytherapymay be used as a boost procedure prior to combination treatment with neoadjuvant external beam radiotherapy and chemotherapy as an upfront procedure in selected cases with the goal of improving detrimental nutritional status and operability

(cT2 and cT3). Another specific indication for endoluminal brachytherapy as a boost within neoadjuvant treatment in operable oesophageal cancer is to reduce the radiation pneumonitis risk and chronic cardiac morbidity by lowering the mean lung [Abou Yehia et al.] and heart doses [Darby et al.] or in cases of inadequate downsizing (<70% SUVmax drop in FDG PET pre-operative restaging) following neoadjuvant radio-chemotherapy. 6.D. Palliative indications in inoperable OC (cT3-4 cN0-3 cM0-1) – boost procedure In advanced locoregional tumours the use of external beam radiotherapy for initial downsizing with or without chemotherapy is important. The addition of endoluminal brachytherapy may be useful when significant downstaging is achieved after excluding a fistula by radiological work up and the residual oesophageal lumen becomes passable by an endoscope. Again, the response adaptive boosting strategy should be applied based on the residual GTV, defining a CTVHR and PTV after EBRT (see section 7 on tumour and target volumes). Chemotherapy may be added in palliative cases only if patients present with ECOG status 0-2. Brachytherapy alone may be indicated in specific situations: for palliation to improve dysphagia in obstructive lesions or for tumour recurrence after external beam radiotherapy to prevent tumour regrowth [Homs et al., Amdal et al., Bergquist et al.]. If the obstruction is so advanced that the oesophageal lumen has become impassable for the brachytherapy applicator, treatment to clear the lumenmust be performed first by a specialized gastro-enterologist.Thismay consist of gradually widening the obstruction with a bougie dilator, or by laser resection.This reopening therapy should quickly be followed by endoluminal brachytherapy to prevent tumour regrowth. If a tube or a stent has been inserted, additional brachytherapy to prevent re-obliteration is also indicated.The primary aimof brachytherapy in obstructive lesions in a palliative setting is to achieve symptom relief from dysphagia for the resting life span. 6.E. Palliative indications to treat tumour local relapse and/or alleviate cancer-related dysphagia – brachytherapy alone 7.A. Curative indications Curative indications require high precision treatment. Planning should be 3D based, using endoscopy, EUS and CT/MRI (see section 9) in order to cover the CTVwith an adequate prescription isodose (fig. 27. 5) 7.A.1. Superficial tumours Superficial tumours that can be treated with curative intent may be de novo lesions as well as small recurrences in previously irradiated areas. In these superficial targets, the extent of the GTV has to be carefully documented by the available diagnostic information: endoscopy, endoluminal ultra sound, CT and MRI. Around the GTV a CTV margin of 1 cm in longitudinal direction is taken to cover microscopic spread. In the radial dimension the thickness 7. TUMOUR AND TARGET VOLUMES