medwireNews: Accounting for treatment response could refine the prognosis provided by the American Thyroid Association (ATA) risk classification in paediatric patients with differentiated thyroid cancer (DTC), research suggests.

Considering treatment response during risk classification “could provide more information to adjust the intensity of follow-up and management strategy for pediatric patients with DTC”, say Suck Joon Hong (Asan Medical Center, Seoul, Korea) and study co-authors.

For example, they found that nearly two-thirds of patients considered at intermediate risk according to ATA criteria (based on tumour size, localised invasion and the number and size of cervical lymph node metastases) had an excellent response to treatment, giving them a very high likelihood of remaining disease-free during follow-up.

At baseline, 22% of the 77 patients (aged 5–18 years) were classified as being at low risk of having persistent or recurrent disease, with 48% being at intermediate risk and 30% at high risk.

During follow-up lasting a median of 5.3 years, 23% of the patients had persistent or recurrent disease, and this varied with ATA category, at 6%, 24% and 74% for the low-, intermediate- and high-risk categories, respectively.

Clinical outcomes were also associated with patients’ best response to initial treatment. Just 3% of the 38 patients with an excellent response developed persistent/recurrent disease, compared with 30% of the three with an intermediate response, 40% of the two with a biochemical incomplete response and 88% of the 21 with a structural incomplete response.

All 13 patients who underwent lobectomy had an excellent treatment response, the researchers note in The Journal of Clinical Endocrinology & Metabolism.

They stress that although only 22% of patients were classified as low risk by the ATA criteria, 49% of the whole cohort had an excellent treatment response, and therefore a very low risk of persistent/recurrent disease.

Of those classified as low, intermediate and high risk, a corresponding 82%, 62% and 4% had excellent treatment responses, and just one of these 38 patients developed persistent/recurrent disease.

Nine patients remained disease-free despite not having an initial excellent response and receiving no further treatment. One of these patients was initially classed as having a structurally incomplete response, due to suspicious lymph node enlargement, but this proved to be benign on further investigation. However, six patients remained disease-free following intermediate responses and two after biochemical incomplete responses.

By Eleanor McDermid

J Clin Endocrinol Metab 2016; Advance online publication

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