Differences in the Recurrence and Mortality Outcomes Rates of Incidental and Nonincidental Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis of 21 329 Person-Years of Follow-up

Abstract

Our meta-analysis strongly suggests the existence of at least two distinct entities of PTMC. Incidental PTMC has different clinical characteristics and a much lower recurrence rate than nonincidental PTMC, suggesting that management protocols should be re-considered. Additional studies with standardized data collection are required to explore potential differences between subgroups of nonincidental PTMC.

Incidental thyroid carcinomas. A retrospective study

“…However, the data resulting from postoperative scintigraphic controls (57.69% of lymph node metastasis detected) gives us the validation of our approach and some authors agree with us (23,(79)(80)(81)(82). On the contrary some Authors do not share this setting (83)(84)(85)(86)(87)(88)(89)(90)(91) and others suggest a stratification of the risk of recurrence based on the presence of BRAF mutation, extrathyroidal extension, lateral neck lymph node metastases, multifocality, TSH levels, molecular markers, high metabolic tumor volume and tumor stage (92)(93)(94)(95)(96)(97)(98)(99)(100)(101)(102).…”

‘Incidental’ and ‘non-incidental’ thyroid papillary microcarcinomas are two different entities

“…Some authors have attributed this to the increasing identification of thyroid nodules during routine imaging for non-thyroidrelated conditions (e.g. radiological evaluations for carotid disease or magnetic resonance imaging for cervical disease) and the widespread use of ultrasound-guided fine needle aspiration cytology (6). As a result of this phenomenon, the frequency of papillary thyroid microcarcinomas (microPTC), defined by the World Health Organization as a PTC of 10 mm or less in the largest dimension (7), has increased considerably during the past two decades (8).…”

“…The clinical significance of microPTC is still debated, and many authors consider it as a non-progressive disease that has no effect on survival (1), (9,10,11,12,13,14,15,16). On clinical and histological grounds there are two different presentations of microPTC (6): (a) 'incidental' microPTC identified postoperatively at histological examination of thyroid specimens following thyroid surgery for benign disease (i.e. compressive goiter) and (b) 'non-incidental' microPTC, diagnosed before surgery at fine needle aspiration (FNA) of small thyroid nodules detected at neck ultrasound or at other diagnostic procedures, or for the presence of nodal metastasis.…”

“…According to some studies, 'incidental' microPTC have an overall excellent prognosis and there is nearly no risk of recurrence or death (17,18), while 'non incidental' microPTC show a more aggressive behavior, eventually associated with lymph node metastases at presentation, neck loco-regional recurrences during follow-up and/or multifocality of the tumor (6,10,16,19,20). However conflicting results are present in literature to date.…”

Therapeutic Strategies and Clinical Outcome in Papillary Thyroid Microcarcinoma: A Multicenter Observational Study

“…However, the widespread use of ultrasonography and fine-needle aspiration cytology (FNAC) markedly increased the rate of preoperative diagnosis [7]. It is still debated if preoperatively and incidentally diagnosed MPTC have different prognoses and should be managed differently [8]. Already in the 12th Annual Cancer Meeting in Porto, Portugal, on March 2003, in the document known as the ‘Porto Proposal' [9], it was suggested that the term papillary ‘microcarcinoma' could be replaced with papillary ‘microtumor' only for a single focus ≤1 cm contained within the thyroid of an adult patient, found incidentally at thyroidectomy performed for other reasons.…”