The extent of surgery for low-risk 1–4 cm papillary thyroid carcinoma: a catch-22 situation. A retrospective analysis of 497 patients based on the 2015 ATA Guidelines recommendation 35

Purpose The adequate extent of surgery for 1–4 cm low-risk papillary thyroid carcinoma (PTC) is unclear. Our objective was to analyze the applicability of the 2015 ATA Guidelines recommendation 35B (R35) for the management low-risk PTC. Methods This multicentre study included patients with low-risk PTC who had undergone total thyroidectomy (TT). Retrospectively we selected those who met the R35 criteria for the performance of a thyroid lobectomy (TL). The aim was to identify the proportion of low-risk PTC patients treated using TT who would have required reintervention had they had a TL in accordance with R35. Results We identified 497 patients (400 female; 80.5%). Median tumor size (mm): 21.2 (11–40). A tumor size ≥2 cm was found in 252 (50.7%). Most of them, 320 (64.4%), were in Stage I (AJCC 7th Edition). Following R35, 286 (57.5%) would have needed TT. Thus, they would have required a second surgery had they undergone TL. The indications for reintervention would have included lymph node involvement (35%), extrathyroidal extension (22.9%), aggressive subtype (8%), or vascular invasion (22.5%). No presurgical clinical data predict TT. Conclusions The appropriate management of low-risk PTC is unclear. Adherence to ATA R35 could lead to a huge increase in reinterventions when a TL is performed, though the need for them would be questionable. In our sample, more than half of patients (57.5%) who may undergo a TL for a seemingly low-risk PTC would have required a second operation to satisfy international guidelines, until better preoperative diagnostic tools become available.