medwireNews: Differentiated thyroid cancer (DTC) is more likely to be metastatic in children than in young adults and is more likely to persist or recur, report researchers.

Nevertheless, the final outcomes in children were “excellent with no mortality and good response to therapeutic interventions”, say Ali Alzahrani (King Faisal Specialist Hospital & Research Centre-Riyadh, Saudi Arabia) and study co-authors.

The findings “reassure us about the long-term outcome of those patients when appropriate management approaches are implemented”, the team writes in Clinical Endocrinology. Current management is “largely empirical”, they note, because of the rarity of the condition.

Alzahrani et al compared 97 cases of paediatric DTC (up to age 20 years) with 213 that arose in adults aged between 20 and 45 years. They chose to study younger adults because those aged 45 years and older have a recognised increased mortality risk with DTC. “Therefore, it would seem inappropriate to lump all adults patients in one category when comparing DTC between adults and children.”

At presentation, paediatric patients had a significantly higher rate of extrathyroidal extension/invasion, at 53.3% versus 34.3% in adults, and higher rates of lymph node and distant metastasis, at 78.0% versus 55.7% and 16.5% versus 3.8%, respectively. But there were no significant differences in tumour subtype or multifocality between the age groups.

Paediatric patients more often required additional interventions, with 60% having persistent disease, compared with 39% of the adult group, at the first follow-up after 6 to 12 months. This difference remained after accounting for treatment approach and was most notable over the first 5 years. By the end of follow-up persistent or recurrent disease was still somewhat higher in paediatric than adult patients, but not significantly so, with rates of 33.7% versus 28.5%.

But none of the paediatric patients died during an average 4.2 years of follow-up, suggesting that the additional interventions were effective. Three adult patients died during an average 5.3 years of follow-up, but not because of DTC.

The findings in the paediatric patients “imply the need for a more careful preoperative evaluation of the extent of the disease and a more meticulous surgical resection of thyroid gland and involved lymph nodes and [radioactive iodine] therapy for distant metastases”, conclude the researchers.

“They also suggest the need for more careful surveillance for persistent/recurrent disease, especially during the first 5 years after diagnosis.”

By Eleanor McDermid, Senior medwireNews Reporter

Clin Endocrinol 2015; Advance online publication

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