Thyroid cancer study in children yields amazing results

Researchers Henrik Krim-Koss, an epidemiologist at the Princess Maxima Center and the Integrated Cancer Center in the Netherlands (IKNL), and Heneke van Santen, a pediatric endocrinologist at the Princess Maxima Center, share their most surprising findings after collecting nearly 30 years of data on Thyroid cancer in patients younger than 25 years of age from analysis. The data come from the Dutch Cancer Registry.

Henrike Karim-Kos and colleagues have published a large public study of children with cancer over the past 30 years. During this research, I discovered a worrying trend. When we looked at cases of childhood cancer, we saw something amazing going on in thyroid cancer. In the last period, the myeloid type was often detected at an advanced stage. ”

To further investigate this trend, the researchers analyzed data from the Dutch Cancer Registry for all children (0-17 years) and young adults (18-24 years) diagnosed with thyroid cancer between 1990 and 2019. This was approximately 839 patients. thirty years. The researchers looked at the two main types of thyroid cancer: medullary (14 percent) and differentiated (86 percent).

Peak medullary thyroid cancer

While the incidence of medullary thyroid cancer has declined in nearly 30 years—with an average annual rate (AAPC) of 4.4 percent—the 1990s saw a clear peak. That was no surprise to Van Santen.

“Carcinoma of the medullary thyroid gland is the most common in MEN syndrome. With this syndrome, the chance of developing medullary thyroid cancer is one hundred percent and there is no good treatment for this type of cancer. In the 1990s, children from families with MEN were offered prophylactic thyroid removal. This The rise in medullary thyroid carcinoma is likely due to the greater number of reconstructive surgeries.”

Karim Kos also believes that the peak is due to the screening effect. “When you start screening, you initially find more tumors, and also more malignancies, but after a while that peak decreases and you find mainly benign tumors thanks to early detection.”

Survival of medullary thyroid cancer

For medullary thyroid cancer, the 10-year survival rate has increased from more than 92 to 96 percent in nearly thirty years. This good chance of survival surprised Van Santen, because there is no good cure for medullary thyroid cancer. These kids come into the office with a lump in their neck. I found it remarkable that they had such a good life expectancy in this study.”

Due to an effective screening campaign and prophylactic thyroid removal in the 1990s in children with family members with MEN syndrome, medullary thyroid carcinomas are now diagnosed mainly in children with sporadic MEN syndrome. This means that other family members were not affected and genetic testing was not possible. Perhaps this explains why we are likely to detect the myeloid type at an advanced stage; “Because it’s unexpected,” adds Karim Kos.

Van Santen suspects that the good life expectancy in this study is explained by the short follow-up time. “If medullary thyroid cancer is diagnosed at age 10, survival at age 30 is still good. Medullary thyroid cancer is a slow-dividing tumor where we often see patients can have towering tumor markers in their blood for years , such as calcitonin, while they often have few complaints about it.” Medullary thyroid cancer develops from cells of the thyroid gland that produce the hormone calcitonin.

High incidence of differentiated thyroid cancer

In thirty years, the number of children and young adults with differentiated thyroid cancer increased – AAPC was 2.6 percent. This increase has already been observed in some other countries. This study shows that differentiated thyroid carcinoma is also on the increase in the Netherlands. It actually surprised me,” says Van Santen, “because he believes the increase in differentiated thyroid cancer cases reported in other countries, such as Japan or America, is partly explained by increased screening. However, in the Netherlands we check very little for thyroid cancer compared to other countries, so this increase seems realistic.”

Neither Karim Koss nor Van Santen can make firm statements about other possible causes of the increase, such as environmental influences and lifestyle factors. In their observational study, they considered only statistical trends and only on the basis of registration data. Therefore, no clinical and pathological data were included in the study.

New guideline for thyroid cancer

For the differentiated type of thyroid cancer, the 10-year survival rate has remained stable at more than 98 percent over nearly thirty years, despite the fact that about 40 percent of children have already developed lymph node metastases, Mainly at the regional level.

“The type of differentiated thyroid cancer is treatable. The question is how do we aggressively treat children with radioactive iodine. For example, can they be less aggressive as we already do with adults? Thyroid cancer in children is really different from that in adults, for example There are more metastases in children,” says Van Santen.

Fortunately, there are also new developments to report in this area. For example, new European guidelines already recommend a slightly less aggressive treatment with radioactive iodine less frequently than before.

Pre-pubertal differentiated thyroid cancer

About three-quarters of all differentiated thyroid carcinomas are diagnosed in girls. The researchers also observed this gender distribution in prepubertal children. This is remarkable, because the female hormone estrogen is believed to play a role in the growth of differentiated thyroid cancer. Therefore, such a clear difference in incidence between girls and boys would be expected to be found only during puberty.

However, Karim Kos warns that this finding may be a coincidence. “The numbers are very small. We might have found a different distribution if we looked over a period of more than thirty years.”

Because of these small numbers, Van Santen hopes to have a European registration of children with thyroid cancer soon. “Then we can see what happens to the numbers when we have ten times those numbers.”


Thyroid Cancer Research:

Lebbink CA, van den Broek MFM, Kwast ABG, Derikx JPM, Dierselhuis MP, Kruijff S, Links TP, van Trotsenburg ASP, Valk GD, Vriens MR, Verrijn Stuart AA, van Santen HM, Karim-Kos HE. Adverse incidence trends of differentiated and myeloid thyroid carcinoma in young Dutch patients over a period of 30 years. Cancers (Basel). 2021 Oct 12; 13 (20): 5104.

Childhood cancer research:

Reedijk AMJ, Kremer LC, Visser O, Lemmens V, Pieters R, Coebergh JWW, Karim-Kos HE. Increasing rates of cancer and staging migration toward advanced disease in young children and adolescents in the Netherlands, 1990-2017. Eur J Cancer. 2020 July; 134: 115-126.

European directive:

Lebbink CA, Dekker BL, Bocca G, Braat AJAT, Derikx JPM, Dierselhuis MP, et al. New national recommendations for the treatment of pediatric thyroid cancer in the Netherlands, European Journal of Endocrinology, 183(4), P11-P18. Retrieved on March 4, 2022 from

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