Abstract
Importance: The prevalence of thyroid cancer has increased significantly. Aggressive subtypes of papillary thyroid cancer (AG-PTC) and poorly differentiated thyroid cancer (PDTC) are malignancies that lie between well-differentiated and undifferentiated cancers. The management of well-differentiated cancers has been established in the literature; however, that of AG-PTC and PDTC needs to be clarified. Objective: To describe the clinicopathological characteristics and genomic landscape of AG-PTC and PDTC and to assess their prognostic value. We primarily aimed to determine the association between persistent or recurrent thyroid cancer and clinicopathological prognostic markers Design: A retrospective chart review of patients with thyroid cancer over the last 10 years Setting: Single center Participants: Patients with AG-PTC or high-grade follicular cell-derived malignancies (HGFM) were included in the analysis. HGFM comprised of patients with PDTC & differentiated high-grade thyroid carcinoma. The clinical presentation, pathological characteristics, molecular markers, specific treatments, and clinical outcomes were compared between the groups. Exposure(s): Main Outcome(s) and Measure(s): Results: Of the 3,244 thyroid cancer charts reviewed, 136 met the criteria for AG-PTC and HGFM. The mean age at diagnosis was 49 years, with a predominance of women. The median follow-up duration was 3 years. The rate of persistent or recurrent disease was 40.3% in the AG-PTC group and 29.3% in the HGFM group, 4.5% died in the AG-PTC group, and 1.8% died in the HGFM group. The presence of vascular, lymphovascular invasion and extrathyroidal extension were associated with a higher incidence of persistent or recurrent disease (Hazard ratio: 2.5, 3.8, and 4.2, respectively; p < 0.05). When the Ki-67 index was divided into five groups, the recurrence rate was higher in the ≥ 20% Ki-67 group compared to lower Ki67 (P-value of 0.017). Although there was a numerical increase in the rate of persistent/recurrent disease among BRAF-mutated patients, it didn’t reach statistical significance. No difference was observed in recurrence based on percentage of aggressive/poorly differentiated tumor involvement. Conclusions and Relevance: Possible prognostic markers for predicting recurrent and persistent thyroid cancers and guiding therapy for AG-PTC and HGFM include vascular/lymphovascular invasion, extrathyroidal extension, and the proliferative index Ki-67.