Stable incidence, improved survival and lower mortality are the results of the first population study in the Netherlands in children and young people under the age of 18 with non-Hodgkin’s lymphoma, over the period 1990 – 2015. These are favorable outcomes, according to Dr. Henrike Karim- Kos, epidemiologist and principal investigator at the Princess Máxima Center for pediatric oncology in Utrecht and senior investigator at IKNL. Karim-Kos is the initiator of the population study because epidemiological research has never been done in the Netherlands into incidence, survival and mortality among children (0-14 years) and young people (15-17 years) with non-Hodgkin.
The researchers analyzed the data of 1001 children and young people. The data comes from the Dutch Cancer Registry (NKR). These present an almost complete picture of the number of children and young people who were diagnosed with non-Hodgkin in the period 1990-2015. Karim-Kos: ‘Therapists were therefore unable to provide parents with good information about their child’s chance of survival on the basis of Dutch data. There were American data, but they are not easily comparable with our Dutch figures. In the United States, children are often treated more intensively and the composition of the population is also different. And we know that certain lymphomas are more common in specific population groups.’
The study distinguishes between the four most common subtypes of non-Hodgkin: lymphoblastic lymphoma (LBL), Burkitt’s lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), and anaplastic large cell lymphoma (ALCL). ‘This subdivision into subgroups provides a lot of information,’ says Karim-Kos. ‘BL, for example, is relatively more common in children up to the age of 15. We see DLBCL more often in young people aged 15 and over. These subtypes also differ in prognosis and treatments, among other things. Patients with LBL and BL were already doing quite well in the late 1990s, compared to patients with DLBCL and ALCL. The improvements are also strongest for the last two groups.’
Less radiotherapy
The study shows that the 5-year survival rate in children and adolescents with non-Hodgkin in the early 1990s was approximately 70 percent. That percentage will increase to almost 90 percent in the years 2010 – 2015. This improved survival has several causes, Karim-Kos suspects. ‘First of all, treatment protocols have changed since the late 1990s. Since then, less radiotherapy has been given for the treatment of lymphomas, because radiotherapy increases the risk of other tumors in the longer term. Furthermore, since 2004, practitioners increasingly prescribe immunotherapy as a treatment intervention. And young people aged 15 – 17 are more often treated by the pediatric oncologist. We know that pediatric oncologists often treat more intensively than adult oncologists and that this leads to better outcomes at group level.’
‘That doesn’t mean that adult oncologists are doing less well,’ says Karim-Kos, ‘but we have seen a significantly better survival of 15-17 year olds since then. Especially in young people with Burkitt’s lymphoma or diffuse large B-cell lymphoma.’ This better survival also leads to a lower mortality. Karim-Kos would also have liked to see the incidence decrease over the years. ‘That has not happened, the incidence has been stable for years, with 38 children and young people being diagnosed with non-Hodgkin every year. On the other hand, the incidence has not increased either. Apparently the risk factors for non-Hodgkin have remained unchanged all these years.’
Zero measurement
Karim-Kos sees the population study as a baseline measurement, as the first benchmark for the quality of treatment in the Netherlands for children and young people with non-Hodgkin’s disease. The study period, 1990 – 2015, was also not chosen by chance. Then, in 2018, the Princess Máxima Center for pediatric oncology in Utrecht opened its doors. This led to further centralization in the diagnosis and treatment of lymphomas. ‘The assumption is that centralization leads to better care, but you want to be sure. This is only possible if you have good comparison material. Hence this baseline measurement.’
Whether centralization of care in the Princess Máxima Center leads to even better outcomes of the treatment of non-Hodgkin’s lymphomas in children and young people will have to be demonstrated by follow-up research. ‘We need new NKR data for this, which will be collected in the coming years. Of course we hope to be able to demonstrate that through further concentration of care we will be able to bring the percentage of survival from 90 to 100 percent. Whether that will work remains to be seen.’
More information
Read the full article:
- Reedijk, A. M., Beishuizen, A., Coebergh, J. W. W., Hoeben, B. A., Kremer, L. C., Hebeda, K. M., … & Karim-Kos, H. E. (2022). Progress against non-Hodgkin’s lymphoma in children and young adolescents in the Netherlands since 1990: Stable incidence, improved survival and lower mortality. European Journal of Cancer, 163, 140-151.