medwireNews: Researchers recommend that treatment of paediatric differentiated thyroid carcinoma (DTC) should focus on limiting morbidity.

Thera Links (University of Groningen, the Netherlands) and study co-authors found a very high survival rate of 99.4% among 170 DTC patients aged 18 years or less who were treated between 1970 and 2013.

However, there was a high rate of surgical complications among the 105 survivors who consented to detailed follow-up for a median of 11.7 years, the team reports in The Journal of Clinical Endocrinology & Metabolism.

Overall, 15.2% of patients had transient hypoparathyroidism and 23.8% developed it permanently, with the rate of permanent hypoparathyroidism being significantly higher among patients who underwent lymph node dissection than among those who did not (34.8 vs 10.2%).

Recurrent laryngeal nerve injury occurred in 12.4% of patients (although status was unknown in 22%), with rates higher in patients with higher tumour stage and those who underwent lymph node dissection.

All patients underwent total, rather than partial, thyroidectomy, and nearly half underwent lymph node dissection, both of which the researchers say are linked to an increased complication risk. But they also note that most patients were treated in centres with relatively little experience of paediatric DTC.

“Centralization of care for pediatric patients with DTC is crucial to reduce treatment-related damage in this young patient group”, they write.

The patients were a median of 15.6 years old at the time of diagnosis, and 83.8% were female. Papillary thyroid carcinoma was most common, affecting 81.0% of patients, with 19.0% having follicular thyroid carcinoma. Metastatic disease was common, with 43.8% of patients having cervical lymph node metastasis and 13.3% having distant metastasis, most commonly sited in the lungs.

Almost all (97.1%) patients received radioactive iodine treatment, of a median cumulative activity of 5.66 GBq, which the team describes as “relatively high” compared with other paediatric DTC groups studied.

“Given the good survival rate, it can be questioned whether children could just as well be treated with lower therapeutic activities as suggested by recent guidelines”, they say, advising very careful consideration of radioactive iodine activity, to avoid adverse effects such as pulmonary fibrosis.

Although most patients remained disease-free, 8.6% had persistent disease, with this being most likely in those with higher tumour stage, lymph node involvement and distant metastasis.

An additional 7.6% of patients had recurrent disease. The team did not identify any predictors of recurrence, and they note that the period of recurrence-free survival ranged from 3.9 to 22.7 years.

“This favors lifelong follow-up of children”, they conclude. They also reiterate the importance of centralised treatment, saying that paediatric DTC surgery in the

By Eleanor McDermid, Senior medwireNews Reporter

J Clin Endocrinol Metab 2016; Advance online publication

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