The International Academy of Cytology Yokohama System for Reporting Breast Cytopathology showed improved diagnostic accuracy

Interobserver agreement and risk of malignancy using the International Academy of Cytology Yokohama System for reporting breast FNA biopsy in a liquid-based exclusive cohort

BACKGROUND

Per the College of American Pathologist's National Breast Fine Needle Aspiration Biopsy (FNAB) Practice Survey, ∼40% of laboratories use liquid-based cytology (LBC) for breast FNAB. The reproducibility of the International Academy of Cytology Yokohama System (YS) for reporting breast FNAB on LBC was explored.

DESIGN

Breast FNAB specimens submitted as LBC only (all ThinPrep) between January 2017 and January 2021 were retrieved. Cases without histopathologic follow-up were excluded. Clinical and radiologic information was collected. One cytologist and six cytopathologists rendered diagnoses per YS. All reviewers were blinded to the original diagnosis and histopathologic follow-up. The risk of malignancy was calculated. Concordance rates were calculated by a weighted Cohen Kappa score (κ).

RESULTS

Review of 110 cases demonstrated substantial to near-perfect agreement between each reviewer (κ = 0.73-0.91) and follow-up histopathology (κ = 0.66-0.85). The agreement was lowest in the inadequate (κ = 0.05) and atypical (κ = 0.04) categories. The lack of concordance in the atypical category was common in cases with low cellularity or incomplete structural features. The risk of malignancy for inadequate, benign, atypical, suspicious for malignancy, and malignant categories were 12.5% (2/16), 3% (2/65), 67%, (8/12) 100% (1/1), and 100% (16/16).

CONCLUSION

Interobserver agreement is excellent using the five YS categories in LBC. Lack of cellularity and incomplete architectural features were barriers to perfect agreement. Established pitfalls in the interpretation of LBC were cause for atypical diagnoses. Continuous training and education are recommended to avoid misdiagnosis because of the nonconventional cytomorphologic features of LBC and to improve inadequate and atypical rates within YS.

Cytomorphological Assessment in Aspirates of Ductal Carcinoma in situ: Correlations with Histopathologic Grade, Architectural Pattern, and Invasion

INTRODUCTION

Fine-needle aspiration biopsy (FNAB) of the breast is an effective and widely adopted diagnostic technique. Histopathologic grading of ductal carcinoma in situ (DCIS) has prognostic significance. In this current study, FNAB of DCIS was reviewed to identify parameters that predict grading, histopathologic architecture, and presence of invasion in DCIS.

METHODS

Aspirates from histopathology-proven cases of DCIS were retrieved and reviewed for cytomorphologic parameters including cellularity, composition, epithelial fragment architecture cellular/nuclear features.

RESULTS

In total 104 aspirates were reviewed. Cytopathologic cellular features - large nuclear size (p = 0.005), prominent nucleoli (p = 0.011), increased nuclear membrane irregularity (p = 0.043), high variation in nuclear size (p = 0.025), and presence of apoptotic figures in epithelial structures (p < 0.001); and background debris (p = 0.033) correlated with a high-grade diagnosis. Cytoplasmic vacuolation (p = 0.034) was seen exclusively in non-high-grade aspirates. Epithelial fragment architecture did not correlate with grading. A predominance (≥50%) of solid aggregates and papillary fragments on FNAB correlated with histopathologically solid (p = 0.039, p = 0.005) and papillary (p = 0.029, < p = 0.001) patterns. No parameter showed correlation with invasion.

CONCLUSION

FNAB is effective in predicting DCIS grading. Epithelial fragment architecture assessment is limited to papillary or solid types, and FNAB cannot predict focal invasion in DCIS.

Assessing the accuracy of the International Academy of Cytology Yokohama System for reporting breast fine needle aspiration biopsy cytology at a Vietnamese oncology centre

BACKGROUND

Fine needle aspiration biopsy (FNAB), accompanied by classification systems for cytology, can offer a cheap and convenient option for the diagnosis of breast cancer in women with suspicious breast lumps. In this study, we aimed to assess the accuracy of the International Academy of Cytology (IAC) Yokohama system in a Vietnamese oncology centre.

METHODS

A retrospective cross-sectional study was conducted from November 2021 to April 2022 at Vietnam National Cancer Hospital. We included patients with full hospital records regarding breast lesions for which FNAB was indicated. A total of 803 patients' FNAB specimens were assessed according to the IAC Yokohama system. The basic characteristics were summarised using the appropriate summary measurements. The risk of malignancy (ROM) was calculated for each classification category.

RESULTS

The median age was 42.7 years (range: 14-85). The mean size of the lesions was 17.9 mm (range: 4-123 mm). We had 215 histopathological reports. The most common benign and malignant diagnoses were fibroadenoma and invasive carcinoma, respectively. The ROM for categories II, III, IV, and V was calculated as 3.4%, 37.5%, 95%, and 99.2% respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 96.4%, 97.2%, 98.5%, and 93.2%, respectively.

CONCLUSION

The IAC Yokohama system offers a good option with which to predict underlying breast pathology using a simple and cheap procedure. However, pathologists require continuous training to ensure accurate interpretation of the slides.

The Use of the International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy

OBJECTIVES

To perform the first meta-analysis regarding the pooled risk of malignancy (ROM) of each category of the Yokohama system for reporting breast fine-needle aspiration, as well as assess the latter's diagnostic accuracy using this new system.

METHODS

Two databases were searched, followed by data extraction, study quality assessment, and statistical analysis.

RESULTS

The "Insufficient," "Benign," "Atypical," "Suspicious," and "Malignant" Yokohama system categories were associated with a pooled ROM of 17% (95% CI, 10%-28%), 1% (95% CI, 1%-3%), 20% (95% CI, 17%-23%), 86% (95% CI, 79%-92%), and 100% (95% CI, 99%-100%), respectively. When both "Suspicious" and "Malignant" interpretations were regarded as cytologically positive, sensitivity (SN) was 91% (95% CI, 87.6%-93.5%) and false-positive rate (FPR) was 2.33% (95% CI, 1.30-4.14%). A summary receiver operating characteristic curve was constructed and the pooled area under the curve was 97.3%, while the pooled diagnostic odds ratio was 564 (95% CI, 264-1,206), indicating a high level of diagnostic accuracy. When only "Malignant" interpretations were regarded as cytologically positive, the pooled FPR was lower (0.75%; 95% CI, .39%-1.42%) but at the expense of SN (76.61%; 95% CI, 70.05%-82.10%).

CONCLUSIONS

Despite Yokohama's system early success, more data would be needed to unravel the system's value in clinical practice.

Tumor-infiltrating lymphocytes in breast FNA biopsy cytology: a predictor of tumor-infiltrating lymphocytes in histologic evaluation

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) are associated with various clinicopathological features. Using cytologic specimens for assessing TILs remains to be established. This retrospective study aimed to establish a practical method to assess TILs in cytologic samples.

METHODS

The authors found 1101 breast fine-needle aspiration biopsy (FNAB) cytology samples in their hospital, and 214 of them met the inclusion criteria. The TILs score was evaluated using histologic slides, and breast cancers were divided into 2 groups: low- (<60%) and high-TILs (≥60%). Training and validation tests composed of 50 breast cancer samples each were constructed. A cytologic TILs (cTILs) score was introduced to evaluate lymphocytes in FNAB cytology and it was compared with histologically evaluated TILs. The cTILs score was calculated by subtracting the number of neutrophils from the number of lymphocytes surrounding the tumor cells.

RESULTS

In the training test, a 2-tier system with low- and high-TILs groups showed a large area under the curve (AUC) (0.943; 95% confidence interval [CI], 0.84-0.99). A cTILs score cutoff value of >8 had 87.5% sensitivity and 90.5% specificity. In the validation test, the AUC was 0.79 (95% CI, 0.6-0.93) whereas sensitivity and specificity were 57% and 89.5%, respectively. When small tumors <0.5 cm were excluded, the AUC improved to 0.93 (95% CI, 0.83-1.0), and sensitivity and specificity were 80% and 88.5%, respectively.

CONCLUSIONS

The cTILs scoring system had acceptable reproducibility and concordance with TILs on histologic samples for tumors ≥0.5 cm. Cytologic evaluation can potentially substitute for histologic evaluation of TILs.