Active surveillance for papillary thyroid cancers – what is the risk of progression?
Reviewed by Christopher Burgess

Papillary thyroid cancers (PTCs) are generally considered to be indolent malignancies with favourable outcomes. Active surveillance (AS) has consequently been trialled as a management option for small PTCs with no evidence of regional lymph node involvement, especially papillary thyroid microcarcinomas (PTMCs - PTCs <1cm in diameter). This meta-analysis sought to determine factors predicting the progression of PTCs under AS. Nine studies with 4166 patients diagnosed with a PTC <2cm in diameter were included. Of these patients, 354 (15%) showed tumour progression during AS, with an average follow-up of nearly 3.5 years (41.58 months). Progression was most frequently due to an increase in volume >50%, then increase in diameter by >3mm, followed by development of lymph node metastasis. This last feature was responsible for evidence of progression in 13% of patients who progressed, representing 2% of all patients under AS. Patient age, sex and tumour size were found not to be associated with a higher risk of tumour progression. Although this is arguably a negative study insofar as no specific risk factors for progression were identified, useful data has nevertheless been provided in terms of an overall rate of risk of progression (15%) and chance of developing lymph node metastases (2%) with consequent possible adverse prognostic implications for patients with small PTCs undergoing AS. The authors conclude that AS may be an appropriate treatment option in a subset of appropriately counselled patients with small PTCs. In the discussion, it is suggested that minimally-invasive radiofrequency ablation (RFA) techniques should be considered as an option between AS and surgery for small PTCs – reference is made to a 2022 meta-analysis of this technique for PTMCs which reported a 93% volume reduction ratio, 64% complete disappearance rate and lymph node metastasis rate of 1%; the overall incidence of complications with RFA was 1.8%.

Recommend with caution: A meta-analysis investigating papillary thyroid carcinoma tumor progression under active surveillance.
Issa PP, Munshi R, Albuck AL, et al.
AM J OTOLARYNGOL
2023;44(6):103994.