ABSTRACT Objectives To determine the percentage of patients with papillary thyroid carcinoma (PTC) who accepted active surveillance as an alternative to surgery in our clinical practice and to describe the clinical characteristics and outcomes of patients with Bethesda category V and VI thyroid nodules who chose active surveillance. Subjects and methods We included 136 PTC patients from the Hospital de Clínicas, University of Buenos Aires without (i) US extrathyroidal extension, (ii) tumors adjacent to the recurrent laryngeal nerve or trachea, and/or (iii) US regional lymph-node metastasis or clinical distant metastasis. PTC progression was defined as the presence of i) a tumor larger than ≥ 3 mm, ii) novel appearance of lymph-node metastasis, and iii) serum thyroglobulin doubling time in less than one year. For patients with these features, surgery was recommended. Results Only 34 (25%) of 136 patients eligible for active surveillance accepted this approach, and around 10% of those who accepted abandoned it due to anxiety. The frequency of patients with tumor enlargement was 17% after a median of 4.6 years of follow-up without any evidence of nodal or distant metastases. Ten patients who underwent surgical treatment after a median time of 4 years of active surveillance (AS) had no evidence of disease after a median of 3.8 years of follow-up after surgery. Conclusion Although not easily accepted in our cohort of patients, AS would be safe and easily applicable in experienced centers.

The therapeutic approach and the follow-up of patients with differentiated thyroid cancer (DTC) is currently individualised according to the risk of recurrence, with a lower tendency to perform remnant ablation (RA) in patients with low risk of recurrence. While response to therapy assessment has been validated for DTC patients treated by total thyroidectomy (TT) and RA, it has not been widely confirmed in patients treated with TT without RA. The aims of this study were to describe the characteristics of the population of patients treated with TT without RA, and to validate the response to therapy. The study included 88 patients followed-up for at least 12 months after surgery. In the entire cohort, 87.9% were female and the mean age was 47.5 years old. Based on the Argentine Intersociety Consensus, 97.7% and 2.3% were classified as low risk and intermediate risk of recurrence, respectively. Patients had an initial excellent response to treatment in 73% of cases, with a disease-free status at the end of follow-up of 85.5%. A minority of patients (1%) presented with an initial structural incomplete response, which was similar at the end of follow-up (1%). On the other hand, 26% of the patients had an initial indeterminate response, although only 13.5% remained with this response at the end of follow-up. These results validate the responses to treatment in DTC patients treated with TT without RA as an effective tool for the dynamic risk stratification. Patients appropriately selected who did not receive RA have an excellent outcome, with a low frequency of structural incomplete response, even lower than that observed in low risk ablated patients.

En la actualidad, el enfoque terapéutico y el seguimiento de los pacientes con carcinoma diferenciado de tiroides (CDT) es individualizado de acuerdo con el riesgo de recurrencia de la enfermedad, con una menor tendencia a ablacionar a pacientes de bajo riesgo de recurrencia. Por otro lado, la evaluación de las respuestas al tratamiento se validó en pacientes tratados con tiroidectomía total (TT) y ablación con radioyodo (RAI), pero son escasos los estudios en pacientes no ablacionados. Los objetivos de este estudio fueron describir las características de una población de pacientes con CDT no ablacionados y validar las respuestas al tratamiento durante el seguimiento. Se incluyó a 88 pacientes con un seguimiento mínimo de 12 meses. El 87,6% eran mujeres y la edad promedio en el momento del diagnóstico fue de 47,5 años. Basados en el Consenso Intersocietario Argentino, el 97,7% de la cohorte fue clasificada como de bajo riesgo y el 2,3% como de riesgo intermedio de recurrencia. Los pacientes presentaron una respuesta inicial excelente en el 73% de los casos, con un estado sin evidencia de enfermedad al final del seguimiento en el 85,5%. Una minoría de los pacientes (1%) presentó una respuesta inicial estructural incompleta, la cual fue similar al final del seguimiento (1%). Por otro lado, el 26% de los pacientes presentó una respuesta inicial indeterminada, aunque solo el 13,5% permaneció con esta respuesta al final del seguimiento. Nuestros datos validan las respuestas al tratamiento en pacientes con CDT que recibieron TT no ablacionados como una herramienta efectiva para la estratificación del riesgo dinámico. Los pacientes apropiadamente seleccionados tratados sin RAI tienen un excelente pronóstico, con una baja frecuencia de respuesta estructural incompleta en el seguimiento, inclusive menor que la de los pacientes de bajo riesgo ablacionados.