Page 10 - Organ motion in children for high-precision radiotherapy - Sophie Huijskens

1.1 | Childhood cancer
Undergoing treatment for childhood cancer has a big impact on the life of children and their families [1, 2]. Suddenly, they have to cope with many medical procedures, doctors, and long hospital stays. This can be an emotionally, frightening, and stressful period. As a result of improved treatment modalities, long-term childhood cancer survival has increased, however, accompanied by late treatment-related adverse events. Because of the young age of these cancer patients, and their potential longevity when surviving childhood cancer, extended surveillance and long-term follow-up procedures are needed to monitor the late consequences of therapy [3].
Incidence and survival rates
Childhood cancer is a rare disease. In the Netherlands, each year around 500 children aged 0-18 years are diagnosed with cancer, which comprises 0.6% of all new cancer cases per year (Figure 1.1) [4]. Childhood cancer is the most common cause of disease-related mortality in children [5]. With continuous developments in diagnostic procedures and multimodal treatment strategies, survival rates have improved rapidly over the past decades, from approximately 25% in the 1960s up to 80% nowadays [6, 7]. With the improved survival rates, the number of childhood cancer survivors has grown impressively. As new treatment strategies and innovative techniques will continue to evolve and be integrated in childhood cancer care, the ambition is that this number continues to grow, as illustrated in Figure 1.2.
Adverse events
Increasing survival rates have also led to increasing incidence of (late) adverse events [8, 9]. These young cancer survivors have a long life expectancy and remain at risk for (late) adverse events due to the malignancy and/or treatment, including second malignancies and toxicities to important healthy organs. From the Emma Children’s Hospital / Academic Medical Center (EKZ/AMC) cohort [10], including 1362 5-year survivors of childhood cancer, almost 75% of survivors had one or more adverse events, and 25% had five or more adverse events. Furthermore, 40% of survivors had at least one severe or life-threatening or disabling adverse event. Specifically, a high or severe burden was observed in 55% of the survivors who received treatment with radiotherapy only. Therefore, solely focusing on cure of cancer is not enough. Although delivering adequate tumor dose to kill the tumor cells is the primary goal in radiotherapy, sparing the vital and long-term functions of adjacent organs is also paramount.
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