Performance of a multigene genomic classifier and clinical parameters in predicting malignancy in a Southeast Asian cohort of patients with cytologically indeterminate thyroid nodules

BACKGROUND

Most thyroid nodules are benign. It is important to determine the likelihood of malignancy in such nodules to avoid unnecessary surgery. The primary objective of this study was to characterize the genetic landscape and the performance of a multigene genomic classifier in fine-needle aspiration (FNA) biopsies of cytologically indeterminate thyroid nodules in a Southeast Asian cohort. The secondary objective was to assess the predictive contribution of clinical characteristics to thyroid malignancy.

METHODS

This prospective, multicenter, blinded study included 132 patients with 134 nodules. Molecular testing (MT) with ThyroSeq v3 was performed on clinical or ex-vivo FNA samples. Centralized pathology review also was performed.

RESULTS

Of 134 nodules, consisting of 61% Bethesda category III, 20% category IV, and 19% category V cytology, and 56% were histologically malignant. ThyroSeq yielded negative results in 37.3% of all FNA samples and in 42% of Bethesda category III-IV cytology nodules. Most positive samples had RAS-like (41.7%), followed by BRAF-like (22.6%), and high-risk (17.9%) alterations. Compared with North American patients, the authors observed a higher proportion of RAS-like mutations, specifically NRAS, in Bethesda categories III and IV and more BRAF-like mutations in Bethesda category III. The test had sensitivity, specificity, negative predictive value, and positive predictive value of 89.6%, 73.7%, 84.0%, and 82.1%, respectively. The risk of malignancy was predicted by positive MT and high-suspicion ultrasound characteristics according to American Thyroid Association criteria.

CONCLUSIONS

Even in the current Southeast Asian cohort with nodules that had a high pretest cancer probability, MT could lead to potential avoidance of diagnostic surgery in 42% of patients with Bethesda category III-IV nodules. MT positivity was a stronger predictor of malignancy than clinical parameters.

Frequent neck US in papillary thyroid cancer likely detects non-actionable findings

BACKGROUND

American Thyroid Association (ATA) low-intermediate-risk papillary thyroid cancer (PTC) patients without structural and biochemical evidence of disease on initial post-treatment evaluation have a low risk of recurrence. Studies have shown that with current ultrasound scans (US) and thyroglobulin assays, recurrences mostly occurred 2-8 years after initial therapy. The ATA recommends that neck US be done 6-12 months after surgery to establish patient's response to therapy, then periodically depending on risk of recurrence. The lack of clarity in recommendations on timing of follow-up US and fear of recurrence leads to frequent tests.

OBJECTIVES

To evaluate the utility of routine neck US in ATA low-intermediate-risk PTC patients with no structural disease on neck US and non-stimulated thyroglobulin <1.0 ng/mL after initial therapy.

METHODS

A retrospective study of 93 patients from Singapore, Saudi Arabia and Argentina with ATA low (n = 49) to intermediate (n = 44) risk PTC was conducted between 1998 and 2017. The outcome was to measure the frequency of identifying structural disease recurrence and non-actionable US abnormalities.

RESULTS

Over a median follow-up of 5 years, five of the 93 patients (5.4%) developed structural neck recurrence on US at a median of 2.5 years after initial treatment. Indeterminate US abnormalities were detected in 19 of the 93 patients (20.4%) leading to additional tests, which did not detect significant disease.

CONCLUSION

In ATA low-intermediate-risk PTC with no suspicious findings on neck US and a non-stimulated thyroglobulin of <1.0 ng/mL after initial therapy, frequent US is more likely to identify non-actionable abnormalities than clinically significant disease.

Use of cabergoline for the management of persistent Cushing's disease in pregnancy

Cushing's disease (CD) is rare during pregnancy and is associated with significant maternal and fetal complications. It is important to control hypercortisolism during pregnancy, either surgically or medically, for a successful maternal and fetal outcome. We report a patient with recurrent CD who was treated with low-dose cabergoline (CAB) for persistent hypercortisolism throughout pregnancy. A 36-year-old woman was diagnosed with CD at the age of 23. She underwent trans-sphenoidal surgery with initial complete remission. However, 4 years after surgery, CD recurred and she underwent Gamma Knife radiosurgery (GKRS). Following GKRS, her cortisol levels remained elevated despite no evidence of visible tumour on pituitary MRI. Medical treatment was commenced with ketoconazole and cyproheptadine. This was changed to CAB as she was keen for pregnancy. She conceived spontaneously and was on CAB throughout pregnancy. She delivered a healthy male neonate, weighing 3195 g at 40 weeks of gestation.

Use of cabergoline for the management of persistent Cushing's disease in pregnancy

Cushing's disease (CD) is rare during pregnancy and is associated with significant maternal and fetal complications. It is important to control hypercortisolism during pregnancy, either surgically or medically, for a successful maternal and fetal outcome. We report a patient with recurrent CD who was treated with low-dose cabergoline (CAB) for persistent hypercortisolism throughout pregnancy. A 36-year-old woman was diagnosed with CD at the age of 23. She underwent trans-sphenoidal surgery with initial complete remission. However, 4 years after surgery, CD recurred and she underwent Gamma Knife radiosurgery (GKRS). Following GKRS, her cortisol levels remained elevated despite no evidence of visible tumour on pituitary MRI. Medical treatment was commenced with ketoconazole and cyproheptadine. This was changed to CAB as she was keen for pregnancy. She conceived spontaneously and was on CAB throughout pregnancy. She delivered a healthy male neonate, weighing 3195 g at 40 weeks of gestation.