25 Oesophageal Cancer

Oesophageal Cancer Brachytherapy

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

The dose per fraction inHDR brachytherapy is crucial with regard to therapeutic benefit. In the reported dose and fractionation schedules, special attention must be paid to the diameter of the applicator used and the oesophageal lumen as this influence significantly the dose at the mucosa and tumour surface, the dose gradient and the volume of over-dosage in the oesophageal wall.

technical correctness when performing endoluminal procedures by using doses per fraction between 2 and 4 Gy, balloon applicators of 1.5-2 cm in diameter or tube applicators of at least 1 cm in diameter and evaluating the reference dose at 5 mm outside of the mucosa. Significant literature for curative treatment using endoluminal brachytherapy in superficial oesophageal cancer is detailed in table 27.2A. 12.B. Curative indications (boost procedure) in inoperable OC (cT2-3 cN0-3 cM0) The multicentre randomized controlled chemoradiotherapy trial published by Okawa et al. demonstrated a clear benefit (p= 0.025) for endoluminal brachytherapy (2 x 5 Gy at 5 mmmucosal depth with a 10mmballoon applicator) versus external beamas additional boost irradiation of 10 Gy in terms of cause-specific survival at 5 years in a subgroup of patients with tumour length less than 5 cm (64% versus 31.5%) [Okawa et al.]. However, in the entire cohort of the 94 analysed patients the cause-specific survival at 5 years did not differ significantly with 27% in the external irradiation alone group versus 38% in the endoluminal brachytherapy combined group (p = 0.385). In the patients with a larger tumour length than 5 cm or stage T3-4 disease, there were no significant differences either (p = 0.290 for cause specific survival and p=0.743 for relapse- free survival). Dose escalated radiotherapy alone may be used exceptionally when chemotherapy is contraindicated. In these cases, endoluminal brachytherapy might be the better choice for local dose intensification rather than external beam radiotherapy. Ishikawa H et al. showed that endoluminal brachytherapy as additional boost after 60 Gy external beam radiotherapy was feasible with excellent 5-year cause-specific and local control rates of 82.6% and 86.3% underlining again the importance of short tumour length (p=0.018) and the good radiation response in the OSCC subtype [Ishikawa et al.]. The addition of chemotherapy to external beam radiation in inoperable tumours with a length of more than 5 cm when endoluminal brachytherapy cannot be performed becomes more relevant. However, Gaspar et al. studied the combination of concurrent chemotherapy and brachytherapy two weeks after completion of external beam radiotherapy.The HDR brachytherapy was given as total dose of 15 Gy with a weekly fraction of 5 Gy (HDR) or to a total dose of 20 Gy with LDR. The dose was prescribed 10 mm from the center of applicator and an applicator with an outer diameter of 4-6 mm was used. The results were not encouraging with 1-year local control of 37% and high toxicity [15, Gaspar et al.]. This finding emphasizes explicitly the significance of appropriate application technique, dose prescription, applicator outer diameter of 1 cm or larger and fraction size. Vuong et al. demonstrated in 70 patients treated with radical intent the significance of total treatment time on local control using upfront HDR brachytherapy with 20 Gy in 5 fractions, twice weekly and specifying dose at 0.5 cm from the mucosa. After completion of brachytherapy external beam radiotherapy with 50 Gy over 5 weeks and concurrent chemotherapy consisting of 2 cycles of cis-platinum and 5-fluorouracil were delivered. The total treatment time was equal or less than 7 weeks.The 75% 2-year local control in this study was excellent. [49, Vuong et al.]. Safaei et al. demonstrated also a positive effect of an upfront brachytherapy boost (10 Gy HDR brachytherapy in 2 fractions in 1 cm from the central axis of a 6 mm external diameter applicator) followed by 50.4 Gy external beam radiotherapy and concurrent cisplatin brachytherapy on tumour control (80% complete remission and

11. MONITORING

The key point during oesophageal brachytherapy is to assure correct positioning of the endo-oesophageal catheter and prevent displacement. Drugs for sedation therefore may be required. In specific situations, special attention must be taken to prevent coughing or vomiting. Intravenous access facilitates the injection of drugs if necessary. The heart rate must be checked (vagus reflex) during the entire procedure and on-line video monitoring by the attending staff is mandatory. Fixation of the catheter to the cheek, neck or tip of the nose by careful taping is essential. A specific mouth piece may be helpful, in particular in PDR or LDR applications because of the longer treatment duration. External markers on the catheter are useful to check the position of the tube at the time of brachytherapy and to compare it to the position at the time of the localisation X-ray. 12.A. Curative indications in superficial OC (T1a or T1b-SM1) Endoluminal brachytherapy in combination with external beam radiotherapy has achieved high 5-year cancer specific survival and overall survival rates in T1a superficial oesophageal cancer with 97% and 84%, respectively. The outer diameter of the used applicators was 16-20 mm, and the prescribed dose was calculated at a depth of 5 mm from the surface of the oesophageal mucosa. In submucosal tumours cT1b, however, the outcomes were inferior (cancer specific survival 55% and overall survival 31%) emphasizing the importance of excluding risk factors for para-oesophageal lymph node involvement such as significant submucosal infiltration >SM1, G3 and angio-lymphatic invasion [Murakami et al]. These excellent 5-year outcomes could be confirmed by Tamaki et al. for endoluminal brachytherapy boost in superficial OC with rates of 86% cause-specific survival and 79% locoregional tumour control. The brachytherapy dose was prescribed 5 mm from the applicator surface and an applicator with a diameter of 15-20 mm was used [Tamaki et al.]. In addition, the Japanese Society of Therapeutic Radiology and Oncology (JASTRO) Study Group has published long-term results of radiotherapy in 141 patients (in 24 institutions) for superficial OC according to the JASTRO guidelines and found excellent 1-, 2- and 3-year survival rates of 95%, 90% and 90% for patients withmucosal cancer and 90%, 81% and 70%, respectively, for patients with submucosal cancer with no difference between external beam and endoluminal brachytherapy (p=0.68 inmucosal lesions and p=0.38 in submucosal tumours) [Nemoto et al.]. Very importantly, this publication emphasized the significance of 12. RESULTS