Each year, approximately 3,000 new patients are diagnosed with esophageal cancer in the Netherlands. About 60% of these patients have potentially curable disease and undergo radiotherapy as part of their treatment. Over the past decade, chances of cure have increased, but the potential development of radiation-related toxicity remains a concern.
This dissertation of Jannet Beukema describes several chapters on the occurrence of various forms of cardiac toxicity before, during, and after radiotherapy in so-called "survivors" following treatment. Both retrospective analyses and two prospective studies were conducted for this purpose.In all chapters, a link was sought between radiation dose parameters and different forms of cardiac toxicity, both clinically (cardiac complications) and subclinically (measured via imaging and/or laboratory tests). The ultimate goal is to gather knowledge to make well-informed decisions in the future when designing and evaluating radiation plans for patients with esophageal cancer.
The main conclusions from this dissertation are that, in older literature, cardiac toxicity was relatively common. With the advent of newer techniques, which have also resulted in lower prescribed radiation doses, prospective studies have observed less cardiac toxicity. However, it has been established that atrial fibrillation occurs more frequently in irradiated patients. The increased incidence of this condition was found to be related to the radiation dose to the atrium. Along with the linear relationship identified between the administered radiation dose to the cardiac muscle tissue and the amount of fibrosis measurable on cardiac MRI, this suggests a local effect of radiotherapy on the atria of the heart.
Furthermore, it is important to recognize that sparing the radiation dose to the heart often results in a higher dose to the lungs. A retrospective analysis demonstrated that this is not always advisable due to the resulting pulmonary toxicity. Finding an optimal balance in radiation treatment plans therefore remains a challenging issue.
