Optimal timing for a repeat fine-needle aspiration biopsy of thyroid nodule following an initial nondiagnostic fine-needle aspiration

Timing of the repeat thyroid fine-needle aspiration biopsy: does early repeat biopsy change the rate of nondiagnostic or atypia of undetermined significance cytology result?

PURPOSE

To determine whether early repeat fine needle aspiration biopsy (FNA) has an effect on adequate or atypia of undetermined significance (AUS) cytology rates in thyroid nodules with inadequate or AUS result in the first FNA.

METHODS

Nodules of patients who underwent repeat biopsy due to insufficient or AUS cytology between 2019-2022 were included. Data of the patients and ultrasonographic, cytological and histopathological results of the nodules were recorded. Additionally, the time between the two biopsies was noted. The first was called "initial" and the second was called "rebiopsy". Five different paired groups were formed according to the time between two consecutive biopsies; before and after 1 month, 45 days, 2 months, 3 months, and 6 months. The groups were compared in terms of adequate and AUS cytological results.

RESULTS

We evaluated 1129 patients with 2187 nodules undergoing FNAB. After excluding nodules with one FNA result and/or missing data, 966 nodules of 628 patients who underwent FNA at least twice were included. Initial cytology was nondiagnostic (ND) in 665 (30.4%) and AUS in 301 (13.8%) nodules. The mean age of the patients was 52.0 ± 11.9 years, and the female sex ratio was 78.8% (n = 495). There were no differences in adequate or AUS rebiopsy results according to the different time interval groups (p > 0.05 for all). AUS result was statistically insignificantly more frequent in nodules with initially AUS nodules when rebiopsy was performed before 1 month in comparison to after 1 month (53.8%, 27.1%; p = 0.054). Accuracy of rebiopsy was also similar in the time intervals groups (p > 0.05 for all).

CONCLUSION

In patients with inadequate or AUS initial biopsy, the rate of adequate or AUS cytology results at rebiopsy did not vary with the timing of repeat biopsy indicating that there may be no need to wait 1 month for a repeat biopsy. In patients with suspicious nodules, biopsy might be repeated before 1 month.

Repetition of thyroid fine-needle aspiration cytology after an initial nondiagnostic result: Is there an optimal timing?

INTRODUCTION

It is suggested to wait at least 3 months to repeat a fine needle aspiration cytology (FNAC) to avoid possible inflammatory cytological changes induced by a previous procedure. This study evaluated the influence of the interval between 2 FNACs in a cohort with a previous non-diagnostic (ND) FNAC. We analysed the occurrence of ND or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) results in the second FNAC, based on the intervals between procedures.

PATIENTS AND METHODS

Retrospective study (2017-2020) including thyroid nodules with a ND result, subjected to another FNAC. Demographic, clinical and echographic data, interval between FNACs and their results were collected. We considered the intervals: ≤/>3 months and ≤/>6 months. Second FNAC results were classified as ND, AUS/FLUS or diagnostic (including the other Bethesda categories).

RESULTS

Included 190 nodules (190 patients - 82.1% women, mean age 60±13.7 years) with a first ND FNAC. The second FNAC results were: ND in 63 cases, AUS/FLUS in 9 and diagnostic in 118 cases. There were no statistical differences in FNAC results performed≤3 months (13 ND, 2 AUS/FLUS, 19 diagnostic) vs >3 months (50 ND, 7 AUS/FLUS, 99 diagnostic; p=0.71). Similarly, there were no statistical differences considering a longer time interval: ≤6 months (32 ND, 3 AUS/FLUS, 59 diagnostic) vs >6 months (31 ND, 6 AUS/FLUS, 59 diagnostic; p=0.61).

CONCLUSIONS

Time interval between FNACs was not relevant to the final cytological result. Early FNAC repetition did not increase the cases of ND or AUS/FLUS.

Fine-needle aspiration cytology repetition in thyroid nodules with non-diagnostic findings or atypia of undetermined significance/follicular lesions of undetermined significance: Does time matters?

INTRODUCTION

After a nondiagnostic (ND) result or findings of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), the current recommendation is for fine-needle aspiration cytology (FNAC) of the thyroid nodule to be repeated after at least 3 months. The aim of this study was to evaluate whether the interval between FNACs has any influence on the final cytological diagnosis.

METHODS

This was a retrospective study including all patients who underwent FNAC for the first time between January 2016 and December 2019 with ND or AUS/FLUS cytological results and then underwent a second FNAC procedure. Demographic, clinical, ultrasound and cytological data were retrieved. 1,497 nodules were evaluated; 535 had a first FNAC result of ND or AUS/FLUS, and 246 of these were re-evaluated with a second FNAC. The cases were grouped according to the timing of the repeat FNAC in two different analyses: < vs. ≥ 3 months and < vs. ≥ 6 months after initial FNAC.

RESULTS

Two hundred forty-six repeat FNACs were performed in 186 patients (76% female, median age 59.5 years). Twenty-two of these procedures (8.9%) were performed within 3 months, and 115 (46.2%) within 6 months of the first FNAC. Second FNAC findings were ND in 121 (49.2%) cases, benign in 103 (41.9%), AUS/FLUS in 8 (3.3%), follicular neoplasm/suspicious follicular neoplasm in 9 (3.7%), suspicious malignancy in 4 (1.6%) and malignancy in 1 (0.4%). Early repetition of FNAC did not significantly influence the final cytological result (< 3 vs. ≥ 3 months, P=0.51; and < 6 vs. ≥ 6 months, P=0.20).

CONCLUSION

This study suggests that the interval in repeat FNAC procedures is not relevant to overall diagnostic performance.

The diagnostic value of second ultrasound-guided fine-needle aspiration for thyroid nodules

OBJECTIVE

This study aimed to investigate the diagnostic value of doing a second ultrasound-guided fine-needle aspiration (US-FNA) for thyroid nodules of different sizes that could not be diagnosed by the first US-FNA.

METHODS

One hundred and forty-three patients (162 nodules) were diagnosed with suspected malignant thyroid nodules in a routine ultrasound examination, but since the diagnosis could not be confirmed by the cytology of the samples collected in the first US-FNA, the patients underwent US-FNA again 3 months later. The ultrasound results, cytology results, and postoperative pathology of these nodules were collected. The nodules were divided into three groups according to the largest diameter (L) of the thyroid nodules: Group 1, L < 0.5 cm, 26 nodules; Group 2, L = 0.5-1.0 cm, 76 nodules; and Group 3, L > 1.0 cm, 60 nodules.

RESULTS

In the second US-FNA, the overall diagnosis rate of the 162 thyroid nodules that could not be given a definitive diagnosis by the first US-FNA was 51.8% (84/162). The definitive diagnosis rates of the nodules in Groups 1, 2, and 3 were 30.8% (8/26), 67.1% (51/76), and 41.7% (25/60), respectively. The diagnosis rate was the highest in Group 2, and the differences between this group and the other two groups were statistically significant (χ²  = 10.489, 8.801, p < 0.05 for both). The diagnostic accuracy rates of Groups 1, 2, and 3 were 100% (8/8), 96.1% (49/51), and 92% (23/25), respectively.

CONCLUSION

Second US-FNA is highly recommended for such nodules.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Atypia of undetermined significance/follicular lesions of undetermined significance: What radiologists need to know

Atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS) refers to an intermediate histologic category of thyroid nodules in The Bethesda System for Reporting Thyroid Cytopathology. Although the risk of malignancy in this category was originally cited as 5-15%, recent literature has suggested higher rates of related malignancy ranging from 38% to 55%. Malignant nodules warrant surgery with total thyroidectomy or thyroid lobectomy, whereas benign nodules can be observed or followed with serial ultrasounds (US) based on their imaging characteristics. The management of nodules with a cytopathologic diagnosis of AUS/FLUS can be difficult because theses nodules lie between the extremes of benign and malignant. The management options for such nodules include observation, repeat fine-needle aspiration, and surgery. The use of molecular genetics, the identification of suspicious US characteristics, and the recognition of additional clinical factors are all important in the development of an appropriate, tailored management approach. Institutional factors also play a crucial role.

Pediatric differentiated thyroid carcinoma: An update from the APSA Cancer Committee

BACKGROUND

Differentiated thyroid carcinomas (DTCs) are rare in young children but represent almost 10% of all malignancies diagnosed in older adolescents.

METHODS

This article reviews the recent literature describing surgical therapeutic approaches to pediatric DTC, associated complications, and long-term recurrence and survival outcomes.

RESULTS

Similar to adult thyroid cancers, pediatric DTCs are more common in females and are associated with thyroid nodules, family history of thyroid cancer, radiation exposure, iodine deficiency, autoimmune thyroid disease, and genetic syndromes. Management of thyroid cancers in children involves ultrasound imaging, fine needle aspiration, and surgical resection with treatment decisions based on clinical and radiological features, cytology and risk assessment.

CONCLUSIONS

Total thyroidectomy and compartment based resection of clinically involved lymph node basins form the cornerstone of treatment of DTC. There is an evolving literature regarding the use of molecular genetics to inform treatment strategies and the use of targeted therapies to treat iodine refractory and surgically unresectable progressive disease.

TYPE OF STUDY

Summary review.

LEVEL OF EVIDENCE

This is a review article of previously published Level 1-5 articles that includes expert opinion (Level 5).

Should we wait 3 months for a repeat aspiration in non-diagnostic/indeterminate thyroid nodules? A cancer centre experience

INTRODUCTION

The Bethesda System recommends repeat fine needle aspiration (rFNA) as a management option for nodules classified under the non-diagnostic (ND) and atypia of undetermined significance (AUS/FLUS) categories. We evaluated the impact of an rFNA in diagnostic resolution and the role of early (≤3 months) vs delayed (more than 3 months) rFNA of nodules initially diagnosed as ND and AUS/FLUS.

METHODS

We retrospectively collected all thyroid FNA performed in a 4-year period with repeat aspiration. For cases initially signed out as ND or AUS/FLUS, diagnostic resolution was defined as a change to a Bethesda System category other than these two on rFNA. Comparison and regression models were fitted to identify the impact of time of rFNA on diagnostic resolution.

RESULTS

In total, 184 cases were initially assigned as ND and 143 as AUS/FLUS, with overall diagnostic resolution rates for the reassessment of these nodules calculated at 70.1% and 62.9%, respectively. For ND cases, time of rFNA was not significantly associated with diagnostic resolution (P > .05). For AUS/FLUS nodules, however, repeat aspiration performed in more than 3 months after the initial diagnosis was 2.5 times more likely to achieve a resolution in diagnosis than early rFNA (P = .024).

CONCLUSIONS

Repeat aspiration of ND and AUS/FLUS nodules helped define diagnosis for the majority of cases, being highly effective in determining correct patient management. For AUS/FLUS nodules, repeat aspiration performed more than 3 months after the initial diagnosis was associated with a higher diagnostic resolution.

The role of repeat fine needle aspiration in managing indeterminate thyroid nodules

BACKGROUND

The Bethesda System is the most widely used for reporting fine needle aspiration (FNA) cytology. It recommends a repeat FNA (rFNA) when initial results are category I or III. It is unclear how often rFNA provides additional diagnostic information. We sought to investigate its utility at our institution.

METHODS

A retrospective chart review was performed of patients who had a category I or III FNA result and underwent rFNA of the same thyroid nodule between 2013 and 2015 at the QE II Health Sciences Centre in Nova Scotia, Canada. Results of initial FNA and ultrasound characteristics, rFNA, demographic data, surgical details, and pathology were collected.

RESULTS

A total of 237 patients (474 thyroid FNAs) were included. Most initial FNAs were category I (82%), the remainder category III (18%). rFNA yielded a different category 60% of the time. However, 60% remained category I or III. rFNA results of benign or malignant were found in 40% of cases; 1% were SFN/SFM. Twenty-seven percent of patients had surgery after rFNA; of those 68% had category I or III rFNA results. Of all nodules that underwent surgery, 46% were malignant, including 32% with category I rFNA results, and 42% category III.

CONCLUSIONS

rFNA for category I and III nodules provided a definitive diagnosis in only 40% of cases, which is important for patient counseling. Malignancy rates at our centre were higher for these categories than predicted by Bethesda. Clinical management should consider institution specific malignancy rates, patient factors, and ultrasound findings.

Incidence and malignancy rates classified by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) - An 8-year tertiary center experience in Thailand

Incidence and Malignancy Rates Classified by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) – An 8-year Tertiary Center experience in Thailand.

Background

Fine-needle aspiration (FNA) of the thyroid is considered the best diagnostic tool for preoperative evaluation of thyroid nodules. The introduction of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) in 2010 provided the opportunity to establish worldwide standard for reporting and terminology guidelines for diagnostic categories. It is recommended that every institution evaluates the risk of malignancy (ROM) in each category for quality improvement process.

Aim

To assess the effectiveness of TBSRTC method at our institution using cyto-histological correlation.

Method

A retrospective 8-year (2010–2017) audit of thyroid FNA done by thyroid specialists at Theptarin hospital. The FNA results were classified according to TBSRTC. Histopathology reports for operated cases were used to correlate cytology and final histopathology.

Results

A total of 2735 thyroid FNA from 2115 patients (mean age 45.7 ± 13.1 years, female 89.8%) were examined. The rates of non-diagnostic, benign, atypia of undetermined significance (AUS), follicular neoplasm, suspected for malignancy, and malignant cases were 21.1%, 66.6%, 4.7%, 2.4%, 1.8%, and 3.3% respectively. There were 188 patients (9%) who underwent surgical resection with available histopathology. Malignancy rates in operated thyroid nodules were 20.0%, 4.2%, 9.4%, 23.5%, 57.1%, and 90.3% for categories 1 to 6, respectively. The sensitivity, specificity, negative predictive value, and positive predictive value were 96.6%, 88.5%, 95.8%, and 90.3, respectively.

Conclusions

Preoperative diagnosis of thyroid nodules using TBSRTC in our hospital was comparable with other studies. The uniform diagnostic criteria of the Bethesda System help avoid misinterpretation while sharing local experience with international benchmarks.

The impact of repeat FNA in non-diagnostic and indeterminate thyroid nodules: A 5-year single-centre experience

INTRODUCTION

FNA is a well-established method for the preoperative diagnosis of thyroid nodules, but limitations still reside among non-diagnostic and indeterminate samples. The objective of the present study was to assess the impact of repeat FNA in thyroid nodules primarily classified as non-diagnostic and indeterminate, with the evaluation of the diagnostic resolution rate after the reassessment of the nodule.

METHODS

We retrospectively collected all cases of thyroid FNA at our institution in the last 5 years that had one or more repeat aspirations of the same nodule, calculating the percentage of samples with change in the diagnostic category. Additional collected data included sex, age and interval between the repeat aspirations.

RESULTS

One hundred and seventy-eight specimens from 167 patients (140 female, 27 male) with a median age of 56 years (range 11-90) were included in the study. Among the 86 cases primarily classified as non-diagnostic, 25 (29.1%) remained in the same category after the first reassessment and only 18 (20.9%) after the second repeat aspiration. Among the 40 indeterminate cases, only 10 (25%) retained their status after the second aspiration, with no change after the third assessment.

CONCLUSION

Repeat aspiration of non-diagnostic and indeterminate thyroid nodules had a positive impact in both groups, with diagnostic resolution rates of 80% and 75%, respectively. The present study therefore endorses the use of such strategy for the initial follow-up of nodules with no definite diagnosis, especially in low-resource centres with limited access to modern molecular technologies.