Association of multicentricity and prognostic factors of papillary microcarcinoma

Abstract

Aim: Multicentric presentation of thyroid papillary microcarcinoma (PMC) is a common feature and difficult to predict preoperatively. The aim of this study was to assess the prognostic importance of the multicentric distribution of papillary microcarcinoma. Material and Methods: A total of 1356 patients who underwent thyroidectomy between 2011 and 2019 were analyzed. Of the 483 (%35.6) patients with papillary thyroid cancer in the final pathology, macro-carcinomas were excluded and 161 (11.9%) patients with only PMC were included in the study. Patients with solitary PMC (Group 1) and multi-centric PMC (Group 2) were compared statistically in terms of prognostic factors such as tumor size, presence of lymphovascular invasion, presence of tumor capsule invasion and extra-thyroidal extension. Thyroglobulin levels and the presence of loco-regional recurrence were monitored during the follow-up period. Results: Solitary PMC was found in 106 (65.8%) of 161 patients, and multicentric MPC was found in 55 (34.2%) patients. Tumor sizes were compared, and a larger mean tumor size was detected in Group 2 (6.4 +/- 2.2 mm vs. 5.6 +/- 2.5 mm) (p<0.05). Prognostic factors such as the presence of capsule invasion and extrathyroidal extension were found to be significantly higher in Group 2 (30.9% vs. 16.3% and 12.7% vs. 2.8%, respectively) (p<0.05). Extra thyroidal extension was detected at a much higher rate (18.5%) in the subgroup of multicentric patients with bilateral involvement (p<0.01). There was no statistical difference between groups in terms of biochemical incomplete response and loco-regional recurrence. Discussion: Poor prognostic factors such as large tumor size, capsule invasion and extra-thyroidal extension are more common in patients with multicentric PMC, especially in those with bilateral involvement.