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Response to therapy assessment effective for dynamic risk stratification in thyroid cancer
An assessment of response to therapy in patients with differentiated thyroid cancer treated surgically without radioactive iodine was effective in modifying initial risk estimates of recurrent or persistent structural disease, according to recent findings.
The assessment tool, based on the 2015 American Thyroid Association risk stratification system, also may be effective to better tailor follow-up and therapeutic approaches, the researchers wrote.
Denise P. Momesso, MD, of the endocrinology service at Universidade Federal do Rio de Janeiro in Brazil, and colleagues evaluated medical records of 507 adults (median age, 43.7 years; 88% women) with differentiated thyroid cancer treated with lobectomy (n = 187) or total thyroidectomy (n = 320) without radioactive iodine to confirm the effectiveness of the response to therapy assessment tool. Follow-up was conducted for a median of 100.5 months.
The main outcome measure of the study was recurrent/persistent structural disease.
During follow-up, 3.6% of the entire cohort, 6.4% of the lobectomy cohort and 1.9% of the total thyroidectomy cohort were diagnosed with recurrent/persistent structural disease. After salvage therapy, 94.4% of those diagnosed with structural disease no longer had evidence of structural disease with additional therapy. Recurrent/persistent structural disease was not linked to excellent response to therapy after lobectomy or total thyroidectomy during follow-up. Twenty-four percent of the lobectomy cohort had indeterminate response based on nonspecific findings at ultrasound (60.9%), stable or declining thyroglobulin antibodies (TgAb; 28.2%) or both (10.9%); recurrent/persistent structural disease was found in 4.3%.
Thirty-three percent of the total thyroidectomy group had indeterminate response based on nonspecific ultrasound findings (33%), positive declining TgAb (25.5%), nonstimulated Tg value between 0.2 ng/mL and 5 ng/mL (20.7%), nonstimulated Tg assay sensitivity more than 0.2 ng/mL (11.3%), positive stable TgAb (1.9%) and nonspecific ultrasound findings linked to nonstimulated Tg value between 0.2 ng/mL and 5 ng/mL or with nonstimulated Tg assay sensitivity greater than 0.2 ng/mL (1.9%) or declining TgAb (3.8%); none with indeterminate response presented with structural disease.
“Our data validate the newly proposed response to therapy assessment in [differentiated thyroid cancer] treated with lobectomy or total thyroidectomy without [radioactive iodine] as an effective tool for dynamic risk stratification over time that should be used to modify initial risk estimates in order to properly identify patients at risk of recurrent/persistent [structural disease and] better tailor follow-up and future therapeutic approaches,” the researchers wrote. “The clinical utility of the modified 2015 ATA risk stratification system as an initial predictor of recurrent/persistent [structural disease] in [differentiated thyroid cancer] patients treated without [radioactive iodine] was also confirmed.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.