Similar frequency findings of a malignant and benign cases in papillary thyroid micro carcinomas

Casril Liebert

Abstract

Similar frequency findings of a malignant and benign cases in papillary thyroid micro carcinomas

Introduction: Papillary thyroid microcarcinomas (PTMC), <10mm maximum diameter, found incidentally in thyroidectomy histological assessment have an excellent prognosis. In the setting of known primary thyroid malignancy, diagnosis of ‘multifocality’ (2 or more foci) may be given, upstaging the disease and potentially overtreating with unnecessary surgery and radio-iodine ablation. This study aims to evaluate the frequency of incidental thyroid microcarcinomas in patients undergoing thyroid surgery for benign and malignant cases. The impact of incidental microcarcinomas was assessed among patients with confirmed thyroid malignancy, focusing on subsequent changes in patient management.
Methods: A retrospective review of thyroidectomy histopathology and multi-disciplinary team (MDT) meeting reports was performed. The frequency of incidental microcarcinomas was calculated and a chi-squared test was performed to assess the independence between incidence rates in cancer versus benign cases.
Results: 120 thyroidectomies (52 cancers, 68 benign) showed 17 (14.2%, n=120) incidental microcarcinomas with no significant difference between the two groups (X² = 1.94, df=1, n=120, p=0.16). 80% of findings in malignant cases were deemed ‘multifocal’ and involved more aggressive management, whereas 85.7% in the benign group had conservative management.
Conclusion: PTMC incidental findings have a similar frequency in malignant and benign cases. This suggests that patient management decisions should be carefully considered for microcarcinomas in malignant cases and active surveillance should be taken to avoid overtreating an otherwise low-risk lesion. A detailed discussion regarding the relevance of incidental PTMC is warranted for all patients and future studies should assess how the clonality of the incidental lesion can assist decision-making.