The significance of cardiac doses received during chemoradiation of oesophageal and gastro-oesophageal junctional cancers

Abstract

Aim: Although radiation-induced cardiotoxicity has been described in patients with breast cancer and Hodgkin's disease, the effect of oesophageal radiotherapy on the heart has not been evaluated. This study was designed to evaluate the dose received by the heart during chemoradiotherapy (CT-RT) for oesophageal cancer, to assess its impact on cardiac function, and explore methods of reducing this dose.

Methods: Cardiac doses were calculated from dose-volume histograms in 15 patients with carcinoma of mid and lower oesophagus undergoing combined technique treatment, in whom pre- and post-treatment multigated acquisition scans were available. Chemotherapy consisted of cisplatin and 5-fluorouracil with or without paclitaxel. The radiotherapy was delivered in two phases to a total dose of 45-50 Gy in 25 fractions.

Results: There was a significant reduction in median ejection fraction after CT-RT (63% to 58%, P = 0.003). The median dose received by the heart using three-dimensional conformal technique was 27.4 Gy (interquartile range 25.8-34.2 Gy). If shielding blocks were not used, as would be the case with conventional planning, the median dose would have been 35 Gy (interquartile range 28.2-37.7 Gy), which is significantly higher (P = 0.002). The use of a three-field technique throughout treatment also reduced the median cardiac dose from 27.4 Gy to 22.7 Gy (P = 0.001) and the volume of heart receiving 70% of total dose from 63.8% to 25% (P = 0.001).

Conclusion: This study highlights the significant dose of radiation received by the heart during oesophageal CT-RT, with consequent reduction in cardiac ejection fraction. Conformal radiotherapy reduces cardiac doses received. The cardiac, as well as the pulmonary, side effects of CT-RT needs to be borne in mind, especially when using this treatment before radical surgery.