Radical Radiotherapy Incorporating a Brachytherapy Boost for the Treatment of Carcinoma of the Thoracic Oesophagus: Results from a Cohort of Patients and Review of the Literature

Abstract ABSTRACT: The optimal treatment for potentially curable carcinoma of the oesophagus unsuitable for surgical resection is unresolved. An intraluminal brachytherapy boost (ILBT) can be used following external beam radiotherapy (EBRT) with or without concurrent chemotherapy (CRT). ILBT increases the dose to the tumour volume substantially while reducing the lung dose but the corresponding high dose to the oesophageal wall may cause increased complications. We report the outcomes of 32 consecutive patients treated with radical radiotherapy. A dose of 45–55Gy in 20–25 fractions with external beam radiotherapy (EBRT) followed by an ILBT boost. Earlier in the series a low dose rate (LDR) brachytherapy technique using 125 Iodine seeds delivering a dose of 20–22Gy at 25–40cGy/h was used. This was later superseded by high dose rate (HDR) treatments delivering 8.5–10Gy in one fraction at 1cm from the catheter. Patients of age below 76 years, of good performance status and with no other medical contraindication were considered for concurrent chemotherapy (CRT) using a planned regime of cisplatin (80mg/m 2 day 1) and 5-flurouracil (1g/m 2 days 1 to 4) in the first and last weeks of radiotherapy (13 patients). The EBRT and ILBT were well tolerated but 8/13 (62%) patients had dose modifications of chemotherapy in one or both cycles due to advanced age, co-morbidity or toxicity. The median follow-up period of surviving patients was 37 months (range 35–39) and the median overall survival for the whole group was 9 months. The overall survival at 1 year was 34.4% (17.6–51.2%), 15.6% (2.8–28.4%) at 2 and 3 years. Local recurrence-free survival at 1 year was 35.3% (15.9–54.7%) and 24.5% (8.3–44.6%) at 2 and 3 years (Fig. 2). Though symptom relief was good there were six cases of ulceration, six of stricture and two fistulae. Biological equivalent for tumour response (BED Gy 10 ) and late radiation effects (BED Gy 3 ) were calculated for the different radiotherapy regimens using equations derived from the linear quadratic model. In this series no advantage was found in terms of local control or survival for patients receiving radiotherapy doses resulting in a BED Gy 10 greater than 75% of the maximum. Similarly, no significant increase in complications was noted in those patients receiving doses resulting in a BED Gy 3 >75% of the maximum. The merits and hazards of the ILBT boost used in radical radiotherapy are discussed and the relevant literature reviewed.