[Incidence and Predictive Factors for Bilaterality in Patients with Papillary Thyroid Carcinoma].

Background: The optimal extent of thyroidectomy for papillary thyroid cancer (PTC) ≥ 10 mm und < 10 mm is still controversial. Therefore, the purpose of this study was to investigate factors predictive for bilaterality in patients with papillary thyroid carcinoma (PTC).

Material And Methods: We retrospectively reviewed 123 PTC patients in a single centre study who underwent either completion or total thyroidectomy and analysed the predictive value of tumour size, histological parameters, multifocality, and lymph node metastases with primary tumour size of ≥ 10 mm and < 10 mm as well as for ≥ 7 mm and < 7 mm.

Results: Out of 123 patients, 26 exhibited bilateral PTC. This was significantly more frequent in patients with a primary tumour size of ≥ 10 mm (77%) compared to a tumour size of < 10 mm (23%) (p = 0.004). Multifocality was found to be an independent predictive factor for bilaterality (p = 5.022e-18). Metachronous lymph node metastases showed a trend for bilateral PTCs (p = 0.0691). These findings were reproducible for the comparison between the ≥ 7 mm and < 7 mm group.

Conclusion: The presence of bilateral PTC appears to be related to the size of the primary tumour ≥ 10 mm. Multifocality is a positive predictor for bilaterality. When multifocality, even with a primary tumour size of < 10 mm, is observed in patients with PTC, total thyroidectomy or completion thyroidectomy may be considered. If lobectomy is performed in patients with PTC, meticulous follow-up is needed to detect hidden malignancies in the contralateral lobe.