High rate incidence of post-surgical adverse events in patients with low-risk papillary thyroid cancer who did not accept active surveillance

We prospectively evaluated 286 patients who attended the Hospital de Clínicas, with a single thyroid nodule <1.5 cm classified as Bethesda category V or VI (PTC). Those patients with no aggressive features were considered as harboring a low-risk PTC and were offered AS or immediate surgery. For patients who opted for AS, surgery was recommended if tumor progression was observed. Post-operative adverse events were recorded for those patients treated with surgery (after AS or immediate surgery).

From 286 eligible patients, 164 harbored a low-risk PTC. Among these, 75% (n = 123) underwent immediate surgery and 25% (n = 41) opted for AS. Within the last group, increase in tumor size more than 3 mm was observed in 14.6 and 4.8% was diagnosed with lymph-node metastases after a median of 37.5 months (range, 12–65) of follow-up. One hundred and thirty five patients underwent surgery: in 123, it was immediate after diagnosis and in 12 after a median of 35 months (range, 12–65) of AS. Both groups had excellent oncological outcomes. The frequency of postoperative adverse events was 24.4%, which was permanent in 9.6% of cases. The immediate-surgery group presented higher incidence of permanent vocal cord paralysis (2.4 vs. 0%); permanent hypoparathyroidism (5.7 vs. 0%) and local complications (4 vs. 2.4%) compared with the AS group, all non-statistically significant.

The high incidence of postoperative complications observed in our media could be avoided if AS was performed as the initial approach in patients with low-risk PTCs. The frequency of tumor growth and LN metastases during AS was similar to other series.