Risk characteristics of papillary thyroid cancer > 1-4 cm is associated with increased tumour size.

Abstract

Recent guidelines recommend total thyroidectomy for papillary thyroid cancers (PTC) larger than 4 cm. For papillary macrocarcinoma with a diameter >1-4 cm, less intensive surgery can be managed, but this is still a matter for debate. The aim of our study was to assess the prevalence of risk factors such as vascular invasion, positive margin, extrathyroidal extension, aggressive histology, lymph nodes and distant metastases associated with a primary PTC tumour with a diameter >1-4 cm, and the association between tumour size and the risk of having one or more of these factors. A retrospective analysis of the medical records of 857 patients who underwent total thyroidectomy between 2000 and 2020, with a final post-operative diagnosis of a PTC >1-4 cm. Overall, less than a half (47.0%) of tumours were associated with at least one risk factor. The prevalence of analysed risk factors, except aggressive histology and a positive margin status, was significantly associated with larger tumour size (>2-4 cm). The optimal cut-off value for a cumulative risk of having one or more risk factors was estimated as 2.0 cm. Patients with a primary tumour < 2.0 cm had almost double less risk (p-value < 0.0001; OR 1.95; 95% CI 1.47-2.58) of having one or more risk factors than patients with PTC ≥ 2.0 cm. In an era of de-escalation, the cut-off value of 2 cm can be helpful in identifying patients with PTC >1-4 cm and lower risk of having aggressive disease providing less extensive treatment approach.