IS NOT-SURGICAL TREATMENT ALWAYS SAFE IN UNIFOCAL CLINICALLY T1A/NODE NEGATIVE PAPILLARY THYROID CARCINOMA (PTC)?

AUTHORS:
F. Pennestrì (Rome, Italy) , A. Laurino (Rome, Italy) , P.F. Procopio (Rome, Italy) , A. Martullo (Rome, Italy) , P. Gallucci (Rome, Italy) , L. Sessa (Rome, Italy) , E.D. Rossi (Rome, Italy) , C. De Crea (Rome, Italy) , M. Raffaelli (Rome, Italy)
Background:
Clinical management of unifocal cT1aN0 papillary thyroid carcinoma (PTC) is controversial, being active surveillance (AS) and/or thermal ablation (TA) possible alternative to thyroid lobectomy (TL). However, non-surgical treatment does not allow evaluation of aggressive pathologic features or occult node metastases, which play a primary role as prognostic factors.
Methods:
Among 4216 thyroidectomies for malignancy (January 2014- November 2023), TL plus ipsilateral central neck dissection (I-CND) was performed in 203 (4.8%) unifocal cT1aN0 PTCs. Completion thyroidectomy (CT) was accomplished in case of positive frozen section examination of removed nodes and within 6 months from index operation in presence of aggressive pathologic features.
Results:
Nodal metastases (pN1a) were detected in 76 patients (37.4%). CT was performed as single or two-step procedure in 63 (31%) cases. The mean number of metastatic nodes was 2.6 (1-8). pN1a patients were significantly younger compared to pN0 patients (37.3±12.2 vs 43.9±11.7, p=0.001). Multifocality, angioinvasion, aggressive variants and extracapsular invasion were detected in 69 (34%), 83 (40.9%), 41 (20.2%) and 5 (2.4%) patients, respectively. Moreover, 89 (43.8%) patients presented ≥2 risk factors. At univariate analysis, age<40 years (p=0.001) and multifocality (p=0.001) were significantly associated with nodal metastases. After backward stepwise logistic regression, age<40 years (OR=4.04, p=0.001) and multifocality (OR=5.45, p=0.001) were identified as independent risk factors for nodal metastases.
Conclusions:
Size alone is not enough to define clinical behaviour of PTC. Forty percent of unifocal cT1aN0 PTC unexpectedly showed combined aggressive pathologic features. AS and TA must be careful evaluated to avoid undertreatment, especially in young population.