34 Chapter 3 Editorial The number of patients with oesophageal cancer treated with curatively intended combined modality strategies such as chemoradiation, either in the neo-adjuvant setting followed by surgery or as definitive treatment, is increasing. Due to the rising incidence of oesophageal cancer in combination with improved outcome, in particular due to the addition of neo-adjuvant chemoradiation prior to surgery, the prevalence of oesophageal cancer survivors will increase significantly [1,2]. Therefore, the absolute number of patients at risk for developing late treatmentrelated toxicity is rising as well. Radiation-induced cardiac toxicity has been studied particularly in patients treated for breast cancer or Hodgkin’s disease, as this toxicity has been considered most relevant because of their more favourable long term survival outcome [3,4]. In these patient groups, higher rates of cardiac events and increased cardiac mortality have been observed during long-term follow up. Recently, a significant relationship between cardiac radiation dose and the risk of cardiac events was found for breast cancer patients treated with radiotherapy [5]. These data can be used to estimate the risk for cardiac complications as a function of radiation dose and baseline risk. In the treatment of oesophageal cancer the radiation dose to the heart is generally much higher than in the aforementioned patient groups. Assuming that the “breast cancer model” for cardiac events can also be used for oesophageal cancer patients, the relative risk on cardiac events will increase more than two-fold compared to the baseline risk. As oesophageal cancer patients often have several cardiovascular risk factors, the absolute access risk for cardiac events is expected to be much higher than in breast cancer. In a recent literature review on cardiac toxicity in oesophageal cancer patients we found an overall risk of severe cardiac events of more than 10 % [6]. The most frequently observed clinical side effects were cardiac ischemia, pleural and pericardial effusions and heart failure. These grade III or higher late toxicities occurred relatively soon after treatment, with a median follow up of 26 to 57 months, and are thus considered clinically relevant. Given the low cure rates of esophageal cancer in these studies, with 3 years survival rates varying between 22% and 45%, the actuarial rates were not reported, but will be much higher. Moreover, given that survival rates after neo-adjuvant chemoradiation and surgery are close to 50% after 5 years, a further increase of severe cardiac toxicity may be expected.
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