The Bethesda system for reporting thyroid cytopathology is effective for predicting thyroid cancer prevalence and providing important prognostic information about cancer type, variant and extent, according to recent study findings presented at the 15th International Thyroid Congress and 85th Annual Meeting of the American Thyroid Association.
“Since inception, the Bethesda system for reporting thyroid cytopathology (TBS) has been widely adopted,” the researchers wrote. “Each category conveys risk of malignancy and recommends next steps, though it is unclear if each category also predicts the type and extend of malignancy. If so, this would greatly expand the utility of TBS by providing prognostic information in addition to baseline malignancy prevalence.”
Trevor E. Angell
Trevor E. Angell, MD, of Brigham and Women’s Hospital and Harvard Medical School, and colleagues conducted a cohort analysis of all patients prospectively enrolled in a thyroid nodule database from 1995 to 2013 to determine primary ultrasound-guided fine-needle aspiration cytology with cancer type and histological features known to affect prognosis and risk for recurrence, including lymph node metastasis, lymphovascular invasion and extrathyroidal extension.
Overall, 1,291 malignancies were identified; the primary cytology was atypia of undetermined significance (AUS) in 130 cases, follicular neoplasm (FN) in 241, suspicious (SUSP) in 411 and malignant in 509.
The cytology most associated with high-risk malignancy, local lymph node metastasis, extrathyroidal extension and margin positivity (P < .001 for all) were AUS, SUSP and malignant.
Follicular variant papillary thyroid carcinoma was 70% of all with AUS cytology followed by 62% with SUSP cytology and 20% with a malignant cytology.
Most high-risk malignancies were diagnosed from malignant cytology (27.5%) followed by SUSP cytology (10.7%) and AUS cytology (4.6%).
There was a increased risk for follicular thyroid cancer with follicular neoplasm cytology compared with all other types of cytology (P < .001).
“In addition to predicting thyroid cancer prevalence, TBS also imparts important prognostic information about the type, variant and thyroid cancer extent and patient outcome when present,” the researchers wrote. “These data extend the utility of TBS classification beyond simply an assessment of cancer likelihood by fostering improved understanding of the risk posed by such a malignancy if confirmed.” – by Amber Cox
Liu X, et al. Short Oral Communication 49. Presented at: 15th International Thyroid Congress and 85th Annual Meeting of the American Thyroid Association (ITC/ATA); Oct. 18-23, 2015; Lake Buena Vista, Fla.
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