Are Papillary Thyroid Carcinomas That Are Candidates for Active Surveillance in Fact Classical Microcarcinomas Restricted to the Gland?

Background: Patients with small papillary thyroid carcinomas (PTC) can currently be maintained under active surveillance (AS). The recommended criteria are the following: adult individual, tumor ≤1 cm and not adjacent to the trachea or recurrent laryngeal nerve, cytology non-suggestive of the aggressive subtype, absence of lymph node (LN) involvement and extrathyroidal extension (ETE) on ultrasonography (US), and absence of clinical distant metastases. This study aimed to evaluate the frequency of the following peri- and postoperative findings in patients who met the criteria for PTC being candidate for AS: tumor > 1 cm, aggressive subtype or vascular invasion, ETE, clinical LN metastases (cN1), and distant metastases.

Methods: We reviewed the results of peri- and postoperative evaluation and histology of patients with a preoperative diagnosis of PTC who would currently be candidates for AS.

Results: There were 124 patients (102 women) with nodules ≤1 cm (range 4-10 mm). All nodules corresponded to papillary microcarcinomas on histology and none of them were > 1 cm. Only one microcarcinoma (0.8%) was of the tall-cell subtype. Vascular invasion was found in 10 microcarcinomas (8%). None of the microcarcinomas were staged as T3b or T4, although microscopic ETE was observed in 25 tumors (20%). In 8 patients (6.4%), central LN involvement was suspected during perioperative evaluation and was confirmed by histology (cN1a). None of the patients had distant metastases (M0).

Conclusion: Findings that define an intermediate risk of recurrence and favor total thyroidectomy were observed in 31.5% of patients with PTC who are candidates for AS.