Low Mitotic Activity in Papillary Thyroid Cancer: A Marker for Aggressive Features and Recurrence.

TitleLow Mitotic Activity in Papillary Thyroid Cancer: A Marker for Aggressive Features and Recurrence.
Publication TypeJournal Article
Year of Publication2024
AuthorsLee-Saxton YJ, Egan CE, Bratton BA, Thiesmeyer JW, Greenberg JA, Marshall TE, Tumati A, Romero-Arenas M, Beninato T, Zarnegar R, Scognamiglio T, Fahey TJ, Finnerty BM
JournalJ Clin Endocrinol Metab
Date Published2024 Mar 30
ISSN1945-7197
Abstract

CONTEXT: The significance of low mitotic activity in papillary thyroid cancer (PTC) is largely undefined.

OBJECTIVE: We aimed to determine the behavioral landscape of PTC with low mitotic activity compared to that of no- and high-mitotic activity.

METHODS: A single-institution consecutive series of PTC patients from 2018-2022 was reviewed. Mitotic activity was defined as no mitoses, low (1-2 mitoses/2 mm2) or high (≥3 mitoses/2 mm2) per the World Health Organization. The 2015 American Thyroid Association risk stratification was applied to the cohort, and clinicopathologic features were compared between groups. For patients with ≥6 months follow-up, Cox regression analyses for recurrence were performed.

RESULTS: 640 PTCs were included - 515 (80.5%) no mitotic activity, 110 (17.2%) low mitotic activity, and 15 (2.3%) high mitotic activity. Overall, low mitotic activity exhibited rates of clinicopathologic features including vascular invasion, gross extrathyroidal extension, and lymph node metastases in between those of no- and high-mitotic activity. PTCs with low mitotic activity had higher rates of intermediate- and high-risk ATA risk stratification compared to those with no mitotic activity (p < 0.001). Low mitotic activity PTCs also had higher recurrence rates (15.5% vs. 4.5%, p < 0.001). Low mitotic activity was associated with recurrence, independent of the ATA risk stratification (HR 2.96; 95% CI 1.28-6.87, p = 0.01).

CONCLUSIONS: Low mitotic activity is relatively common in PTC and its behavior lies within a spectrum between no- and high-mitotic activity. Given its association with aggressive clinicopathologic features and recurrence, low mitotic activity should be considered when risk stratifying PTC patients for recurrence.

DOI10.1210/clinem/dgae203
Alternate JournalJ Clin Endocrinol Metab
PubMed ID38554391
Related Faculty: 
Theresa Scognamiglio, M.D.

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