Changes in thyroid fine needle aspiration practice during the COVID‐19 pandemic

Abstract

Purpose To investigate the diagnostic accuracy of a different sample preparation protocol for fine needle aspiration cytology (FNAC) of thyroid nodules established during the COVID‐19 pandemic. Methods From April 2020, conventional smears during FNAC were ceased according to World Health Organization recommendations due to the increased infection risk for operators, and a new protocol using only liquid‐based cytology (LBC) was adopted. FNACs performed between April and July 2020 (COVID‐19 group) were retrospectively compared with those from December 2019 through March 2020 (Pre‐COVID‐19 group). The distribution of diagnoses based on SIAPEC‐IAP categories and the concordance between cytological and histological results were compared using the chi‐squared test. Results Categories based on FNAC for 90 and 82 thyroid nodules in the Pre‐COVID‐19 and COVID‐19 groups showed no significant difference in distribution (P = .081), with the following respective cases (and percentages): TIR1, 7 (8%) and 8 (10%); TIR1C, 0 (0%) and 6 (7%); TIR2, 59 (66%) and 55 (67%); TIR3A, 8 (9%) and 5 (6%); TIR3B, 1 (1%) and 2 (3%); TIR4, 5 (6%) and 1 (1%); and TIR5, 10 (12%) and 5 (7%). Among patients with potentially malignant lesions, surgery was performed for 12/16 (75%) nodules in the Pre‐COVID‐19 and 7/8 (88%) nodules in the COVID‐19 groups, with no significant differences between cytological and histological diagnoses (P = .931). Conclusion The new LBC‐only protocol provided similar diagnostic accuracy in comparison with conventional smears, and can be effectively applied during a viral pandemic improving operator safety.

Examining the impact of several factors including COVID‐19 on thyroid fine‐needle aspiration biopsy

“…According to the studies by Giannoula et al 32 and Vrachimis et al, 33 it has been suggested that delaying TFNAB for most asymptomatic thyroid nodules due to COVID‐19 does not negatively impact the outcomes in thyroid cancers, provided that symptoms and signs of urgent intervention are taken into account. The research by Rossi et al supports these conclusions, showing no difference in the diagnostic accuracy of TFNAB of thyroid nodules based on vaccination status and even during the pandemic 34 …”

Digital diagnostic cytopathology: Has the pandemic brought us closer?

“…The pandemic also helped, albeit indirectly, to overcome some of the well‐known issues of digitising a cytological slide, such as the large spread of the material on the slide leading to large‐sized WSI files, the frequent blood and foreign material contamination, and the problem of 3D‐clustering of cell groups with the need for an advanced Z‐stacking. For example, even though not in a digital setting, the pandemic has forced the use of liquid‐based cytology (LBC) methods to avoid the potential spread of the virus during a normal fine needle aspiration procedure with conventional smear preparation, and there is evidence that the diagnostic performance in terms of diagnostic yield is comparable to conventional cytology 27 . This is important because LBC preparations provide more homogenous and regular specimens which could be advantageous for WSI scanning 28 …”

“…For example, even though not in a digital setting, the pandemic has forced the use of liquid-based cytology (LBC) methods to avoid the potential spread of the virus during a normal fine needle aspiration procedure with conventional smear preparation, and there is evidence that the diagnostic performance in terms of diagnostic yield is comparable to conventional cytology. 27 This is important because LBC preparations provide more homogenous and regular specimens which could be advantageous for WSI scanning. 28 So, in conclusion, the pandemic has not brought us closer to a digital diagnosis in cytopathology in the same way as in surgical pathology-given that no formal approval has been licensed to WSI for diagnostic use in cytology, with CAP advocating that more evidence is required-but has definitely led to an increased awareness of the issues related to digital cytology and the potential benefits that may come from the adoption of WSI for this field of pathology.…”

Thyroid surgery during the COVID-19 pandemic: difficulties – how to improve

“…showed that the LBC method provided similar diagnostic results to the conventional method and can be applied during a pandemic and provide more safety. No significant differences between cytological and histological diagnoses were noticed in patients with potentially malignant lesions [ 25 ].…”