Endocrine Abstracts

Introduction: Papillary thyroid microcarcinomas (PTMC) are defined as thyroid cancers with a maximum tumour diameter of 10 mm. These neoplasms have become a topic of significant interest, particularly concerning their active surveillance and conservative management. Incidental papillary microcarcinomas (I-PTMCs) discovered post-operatively on histology are less studied compared to lesions identified pre-operatively via FNA, especially regarding demographics, histopathological features, and long-term outcomes. We aimed to perform one of the first large, 10-year retrospective studies assessing differences in outcomes between these subgroups, to delineate the clinical recommendations for follow-up of these individuals.

Methods: This single-centre retrospective cohort study assessed St. James University Hospital Head and Neck MDT data records from 2013-2023, identifying 2,015 patients diagnosed with thyroid neoplasms during this period. 59 incidental, and 57 non-incidental papillary microcarcinomas were included in the final analysis. Information on demographic, histopathological and treatment methods were collected. Recurrence-free and overall survival outcomes were analysed with Kaplan-Meier curves and compared by log-rank testing.

Results: Among demographic and histopathological factors, statistically significant differences were found between non-incidental and incidental subgroups related to neck dissections performed (26.32% v. 1.69%, P < 0.001), positive nodal metastases (19.30% v. 1.69%, P = 0.002), size of largest foci (7.37 mm v. 3.89 mm P < 0.001) and aggressive subtype variants present (19.30% v. 1.69% P = 0.036). However, recurrence-free survival (P = 0.156) did not differ significantly between the two groups.

Conclusion: There is a paucity of solid evidence and definitive guidelines on the management of incidental papillary microcarcinomas. Despite evidence of a less aggressive presentation, no differences in recurrence-free survival were observed, suggesting similar, or less careful monitoring compared to microcarcinomas discovered pre-operatively.