medwireNews: Researchers demonstrate the existence of a low-risk group of paediatric patients with well-differentiated thyroid carcinoma, who could potentially be treated with lobectomy rather than total thyroidectomy.

The team found that 53.4% of 73 patients studied met the American Thyroid Association (ATA) criteria for low-risk disease, having cancer that was confined to the thyroid and stage N0/Nx or incidental microscopic N1a.

And 21.9% of patients met a more stringent set of criteria for very low risk, having unifocal tumours no larger than 4 cm and lacking prior radiation exposure, family history of thyroid carcinoma, high-risk histology, tumour predisposition syndromes, lymphovascular invasion and lymph node and/or distant metastasis.

The patients had all been treated at the same institution between 2004 and 2015. They were aged an average of 13.4 years and 63% were female.

Jonathan Wasserman (Hospital for Sick Children, Toronto, Ontario, Canada) and study co-authors note that all except three had undergone total thyroidectomy. Although contrary to the accepted approach in adults, this is in line with current ATA guidelines and has been the standard of care for decades, based on an increased likelihood of multifocal and bilateral disease in children, as well as an increased recurrence risk.

“Nevertheless, our data indicate that there is a substantial group of low-risk children that might qualify for lobectomy”, they write in Clinical Endocrinology.

The researchers concede that their data cannot address recurrence and survival in low-risk children who undergo lobectomy, but add that the lack of data is a consequence of the long-standing recommendation for near-universal total thyroidectomy. What data exist are mostly from children treated before this recommendation was put in place, since when there have been major advances in the reliability of preoperative imaging and therefore in the accuracy of staging.

Wasserman and team stress the importance of thorough preoperative staging by experienced practitioners, noting: “A sub-optimal study may result in underestimation of disease burden and inadequate primary therapy.”

But they also point out that lobectomy reduces the risk of surgical complications and preserves at least some thyroid function.

“The data from our analysis demonstrate that a substantial population of low-risk and very low-risk patients exists within a tertiary care paediatric referral centre”, the researchers conclude. “We propose that such patients may benefit from less-than-total thyroidectomy alone, with completion thyroidectomy deferred, if there are no worrisome pathologic findings.”

By Eleanor McDermid

Clin Endocrinol 2016; Advance online publication

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