Accuracy of the International Academy of Cytology Yokohama system of breast cytology reporting for fine needle aspiration biopsy of the breast in a dedicated breast care setting

Clinicoradiological Predictors of Malignancy in the Atypical Category by the Yokohama System for Reporting Breast Fine-Needle Aspiration Cytopathology

INTRODUCTION

The atypical category (AC) by the Yokohama system is an indeterminate group characterized by predominantly benign cytomorphology of the lesions, with some uncommon features that may be seen in malignancy in breast fine-needle aspiration. The risk of malignancy (ROM) varies from 13% to 25%. Its management depends on the clinical and radiological findings. Since most cases are benign, selecting cases for further management may benefit patients. This study aims to determine the clinicoradiological predictors for malignancy in AC breast cytology.

MATERIALS AND METHODS

All AC breast fine-needle aspirations at Chiang Mai University Hospital from 2015 to 2019 were selected from an electronic database for cyto-histological correlation and ROM calculation. The clinicoradiological factors calculated by ROM were analyzed using multivariable logistic regression for malignant prediction and screening scores.

RESULTS

There were 218 aspirates from patients aged 15-77 years. The lesion size ranged from 0.2 to 9.2 cm. The ROM was 27.5%. The significant predictors were age ≥40 years (P = 0.03), lesion size ≥1 cm (P< 0.01), and suspicious calcification on imaging (P < 0.01). The ROM was numerically increased in Breast Imaging-Reporting and Data System 5. The screening score showed 88.3% sensitivity, 55.1% specificity, 42.7% positive predictive value, and 92.6% negative predictive value.

CONCLUSIONS

The AC diagnosis varies from benign to malignant. Age ≥40 years, a lesion size ≥1 cm, and suspicious calcification/Breast Imaging-Reporting and Data System 5 are useful predictors of malignancy. Selecting cases according to screening scores can reduce invasive procedures by up to 43.1%.

Breast fine-needle aspiration cytology in the era of core-needle biopsy: what is its role?

Fine-needle aspiration cytology (FNAC) has long been recognized as a minimally invasive, cost-effective, and reliable diagnostic tool for breast lesions. However, with the advent of core-needle biopsy (CNB), the role of FNAC has diminished in some clinical settings. This review aims to re-evaluate the diagnostic value of FNAC in the current era, focusing on its complementary use alongside CNB, the adoption of new approaches such as the International Academy of Cytology Yokohama System, and the implementation of rapid on-site evaluation to reduce inadequate sample rates. Advances in liquid-based cytology, receptor expression testing, molecular diagnostics, and artificial intelligence are discussed, highlighting their potential to enhance the diagnostic accuracy of FNAC. Despite challenges, FNAC remains a valuable diagnostic method, particularly in low-resource settings and specific clinical scenarios, and its role continues to evolve with technology.

Real-World Diagnostic Accuracy of the On-Site Cytopathology Advance Report (OSCAR) Procedure Performed in a Multidisciplinary One-Stop Breast Clinic

Fine-needle aspiration (FNA) cytology has been widely used for the diagnosis of breast cancer lesions with the objective of differentiating benign from malignant masses. However, the occurrence of unsatisfactory samples and false-negative rates remains a matter of concern. Major improvements have been made thanks to the implementation of rapid on-site evaluation (ROSE) in multidisciplinary and integrated medical settings such as one-stop clinics (OSCs). In these settings, clinical and radiological examinations are combined with a morphological study performed by interventional pathologists. The aim of our study was to assess the diagnostic accuracy of the on-site cytopathology advance report (OSCAR) procedure on breast FNA cytologic samples in our breast OSC during the first three years (April 2004 till March 2007) of its implementation. To this goal, we retrospectively analyzed a series of 1820 breast masses (1740 patients) radiologically classified according to the American College of Radiology (ACR) BI-RADS lexicon (67.6% being either BI-RADS 4 or 5), sampled by FNA and immediately diagnosed by cytomorphology. The clinicoradiological, cytomorphological, and histological characteristics of all consecutive patients were retrieved from the hospital computerized medical records prospectively registered in the central information system. Histopathological analysis and ultrasound (US) follow-up (FU) were the reference diagnostic tests of the study design. In brief, we carried out either a histopathological verification or an 18-month US evaluation when a benign cytology was concordant with the components of the triple test. Overall, histology was available for 1138 masses, whereas 491 masses were analyzed at the 18-month US-FU. FNA specimens were morphologically nondiagnostic in 3.1%, false negatives were observed in 1.5%, and there was only one false positive (0.06%). The breast cancer prevalence was 62%. Diagnostic accuracy measures of the OSCAR procedure with their 95% confidence intervals (95% CI) were the following: sensitivity (Se) = 97.4% (96.19-98.31); specificity (Sp) = 94.98% (92.94-96.56); positive predictive value (PPV) = 96.80% (95.48-97.81); negative predictive value (NPV) = 95.91% (94.02-97.33); positive likelihood ratio (LR+) = 19.39 (13.75-27.32); negative predictive ratio (LR-) = 0.03 (0.02-0.04), and; accuracy = 96.45% (95.42-97.31). The respective positive likelihood ratio (LR+) for each of the four categories of cytopathological diagnoses (with their 95% CI) which are malignant, suspicious, benign, and nondiagnostic were 540 (76-3827); 2.69 (1.8-3.96); 0.03 (0.02-0.04); and 0.37 (0.2-0.66), respectively. In conclusion, our study demonstrates that the OSCAR procedure is a highly reliable diagnostic approach and a perfect test to select patients requiring core-needle biopsy (CNB) when performed by interventional cytopathologists in a multidisciplinary and integrated OSC setting. Besides drastically limiting the rate of nondiagnostic specimens and diagnostic turn-around time, OSCAR is an efficient and powerful first-line diagnostic approach for patient-centered care.

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.

Performance of breast fine needle aspiration as an initial diagnostic tool: A large academic hospital experience

BACKGROUND

The clinical performance of the Yokohama reporting system for breast cytology remains uncertain.

METHODS

In this study, we retrospectively evaluated 318 breast fine needle aspirations (FNABs) from Los Angeles County Hospital over a five-year period, analysing data for breast cytology, histology, and radiology.

RESULTS

Among 318 breast FNAB cases, 78.3% (249/318) were benign and 5.3% (17/318) malignant. Of 83 cases with follow-up histology, 14.5% (12/83) were insufficient, 66.3% (55/83) were benign, and 16.9% (17/83) were malignant. Of 55 benign cases, 61.8% (34/55) were fibroadenoma and 9 (9/55, 16.4%) were fibrocystic changes. Two cases were diagnosed as "atypical" but confirmed "benign" on core needle biopsy (CNB). No "suspicious" cases were found. Seventeen malignant cases were confirmed by CNB, including 70.6% (12/17) invasive ductal carcinoma, 11.8% (2/17) invasive lobular carcinoma, and one malignant phyllodes tumour. Receptor studies on cell blocks of three malignant cases showed concordant results with CNB results. In addition, 82.2% (148/180) of lesions with Breast Imaging-Reporting and Data System (BI-RADS) scores of 2 or 3 were benign and 92.3% (12/13) BI-RADS score 5 lesions were malignant on FNAB. Finally, 90% (67/74) of BI-RADS 4a lesions were benign, and 97% (36/37) of fibroadenomas were BI-RADS score 4a.

CONCLUSION

This, by far the largest U.S. breast cytology study, showed 93.3% sensitivity, 100% specificity, 100% positive predictive value, and 98.2% negative predictive value for breast FNAB. Women with breast lesions of BI-RADS score 3 or less have a low risk of malignancy; FNAB would contribute to the reduction of excisional biopsies. FNAB can be considered as an initial diagnostic tool for BI-RADS 4 mass/lesions and satellite lesions, as well as for triaging patients.

Risk of Malignancy in Breast FNAB Categories, Classified According to the Newly Proposed International Academy of Cytology (IAC) Yokohama System

BACKGROUND

A new category system comprising five classes (C1-insufficient material, C2-benign, C3-atypical, C4-suspicious, and C5-malignant) has been proposed by the International Academy of Cytology (IAC) for fine needle aspiration biopsy cytology (FNAB) for proper diagnosis of breast cancer.

AIMS AND OBJECTIVES

This study is designed to categorize institutional FNAB data according to the new system and calculation of the absolute risk of malignancy (ROM), sensitivity, specificity, positive predictive values, false negative and false-positive rate.

STUDY DESIGN

We conducted a retrospective cross-sectional study involving 2133 cases collected between June, 2008 and August, 2019, at Foundation University Medical College's Department of Histopathology and the Surgery and Oncology Department at the Fauji Foundation Hospital. All cases fulfilling the inclusion and exclusion criteria were retrieved from the archives and reviewed by two expert pathologists. Matching histopathology was compared with the cytology reports for concordance or discordance of results.

FINDINGS

We found 6.9% (n = 147) insufficient, 65.8% (n = 1403) benign, 7.2% (n = 153) atypical, 7.5% (n = 160) suspicious and 12.6% (n = 270) malignant cases. Cyto-histological correlation was found in 421 cases from the year 2014 to 2019 with 370 concordant and 51 discordant cases. The maximum number of concordant cases was 151 in the C5 category and discordant cases had a diagnosis of C3 and C4 on cytology with 16 cases in each category. The calculated values of ROM were 45.45%, 10.3%, 30.6%, 82.79% and 99.34% from C1 to C5, respectively. We calculated 83.42% absolute sensitivity and 85.24% specificity. The positive predictive value for category 3, 4 and 5 was 67.34%, 82.7% and 99.34%, respectively, while false-negative rate was 7.9% and false-positive rate was 0.66%.

CONCLUSION

The ROM for C1 category calculated from this study is quite high (45.45%) compared to previous studies; therefore, it is recommended to perform core needle biopsy in all these cases. The higher sensitivity and specificity of this method of diagnosing malignant lesions supports its use.

The role of the IAC Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy and the ACR Breast Imaging-Reporting and Data System in the evaluation of breast lesions

BACKGROUND

Stratification of breast lesions for appropriate management is achieved through an integration of clinical examination, imaging, and fine needle aspiration biopsy (FNAB). The current study aimed to evaluate the combined effectiveness of the widely used Breast Imaging-Reporting and Data System (BI-RADS) with the recently proposed International Academy of Cytology (IAC) Yokohama System for Reporting Breast Fine Needle Aspiration Biopsy Cytopathology.

METHODS

A retrospective analysis was done on all breast FNABs from 2016 through 2020. The cases were categorised according to the IAC Yokohama System. Histopathological correlation of the BI-RADS and IAC Yokohama System was performed. The rate of malignancy (ROM) for each category of the BI-RADS and IAC Yokohama System was calculated.

RESULTS

The ROM values for categories I to V were 38%, 0.6%, 21.9%, 100%, and 97%, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FNAB with category III assumed as malignant were 98.9%, 85%, 76.1%, 99.3%, and 89.5%, respectively. With category III assumed as benign, these indices were 90.8%, 98.9%, 97.5%, 95.7%, and 96.2%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of BI-RADS were 91.5%, 81.9%, 72%, 95%, and 85.1%, respectively.

CONCLUSIONS

FNAB is still an indispensable test in the evaluation of breast lesions. The utilisation of the IAC Yokohama reporting system for breast cytology in conjunction with ACR BI-RADS aids in better stratification of lesions.

Categorization of Breast Fine Needle Aspirates Using the International Academy of Cytology Yokohama System Along with Assessment of Risk of Malignancy and Diagnostic Accuracy in a Tertiary Care Centre

Context:

The International Academy of Cytology Yokohama System has developed a standardized system of reporting breast cytology by classifying them into five categories – insufficient, benign, atypical, suspicious, and malignant. Numerous studies conducted at different centers are required to confirm the risk of malignancy of the different categories.

Aims:

The main objectives of our study were to classify breast fine needle aspirates according to the IAC Yokohama system and assess the risk of malignancy, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.

Settings and Design:

It was a retrospective study done over a period of 2 years from January 2018 to December 2020.

Materials and Methods:

All breast FNAs done in the above period were retrieved and classified into five categories according to the Yokohama system. Histopathological diagnosis was also retrieved wherever available.

Statistical Analysis Used:

Using a histopathological diagnosis as the gold standard, sensitivity, specificity, PPV, NPV, and diagnostic accuracy were calculated. For each of the five categories, the risk of malignancy was also assessed.

Results:

Out of the 554 breast fine needle aspirates, 242 had histopathological correlation. The risk of malignancy for insufficient, benign, atypical, suspicious, and malignant categories were 5%, 1.5%, 17.4%, 81.8%, and 100%, respectively. Maximum sensitivity (97.2%) was achieved when atypical, suspicious, and malignant cases were considered as positive test results. The highest specificity (100%) was observed when only malignant cases were considered as positive test results, whereas maximum diagnostic accuracy (96.4%) was noted when the malignant and suspicious category was included in positive test results.

Conclusion:

The IAC Yokohama system is an excellent system for accurately diagnosing breast fine needle aspirates with greater reproducibility of reports and better communication between the pathologist and clinician.

Risk Stratification of Breast Fine-Needle Aspiration Biopsy Specimens Performed without Radiologic Guidance by Application of the International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Cytopathology

BACKGROUND AND OBJECTIVE

The International Academy of Cytology (IAC) Yokohama system for reporting breast fine-needle aspiration biopsy (FNAB) cytopathology has been proposed to standardize breast FNAB reporting. The aim of this study was to categorize breast FNAB cases performed by palpation without radiological guidance according to the IAC system, establish the risk of malignancy (ROM) for the categories and assess the system's utility, pitfalls, and implications in low-resource/financial constraint settings.

METHODS

A retrospective analysis of palpation-guided FNAB of breast lesions performed without radiological guidance between January 2016 and December 2019 was carried out and was correlated with follow-up biopsies wherever available. A total of 1,089 cases were recategorized using the IAC Yokohama system. Histopathology follow-up was available for 400 cases. The data were analysed for ROM, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS AND DISCUSSION

Out of 1,089 cases, 4.3% (n = 47) cases were categorized as insufficient, 82% (n = 893) as benign, 2.8% (n = 31) as atypical, 2.7% (n = 29) as suspicious of malignancy, and 8.2% (n = 89) as malignant. Some 400 cases had a follow-up biopsy, based on which, the ROM for the categories were 33.3%, 0.4%, 37.5%, 96%, and 100%. The NPV for the benign category was 99.6%. The PPV of the malignant category was 100%, that of combined suspicious of malignancy and malignant categories was 99%, and of combined atypical, suspicious of malignancy, and malignant was 90.6%.

CONCLUSION

The IAC Yokohama system is useful in standardizing the reporting of cytopathology of breast lesions. FNAB with radiological guidance is ideal but in cases of finance/resource constraints, FNAB by palpation alone is satisfactory if the test result is in the benign, suspicious of malignancy, or malignant categories, which constitute 91.5% of the cases in this study. A repeat ultrasound-guided FNAB and/or core needle biopsy should be recommended for cases in the insufficient/inadequate or atypical categories.

Implementation of the International Academy of Cytology Yokohama standardized reporting for breast cytopathology: An 8-year retrospective study

BACKGROUND

The International Academy of Cytology (IAC) Yokohama reporting system was recently proposed to serve as a standardized diagnostic platform for the cytological interpretation of breast fine needle aspiration biopsy (FNAB). Five cytological categories were suggested, linked to a certain risk of malignancy (ROM). The aim of this study was to assess the potency of this newly proposed reporting guideline, with a review of literatures.

METHODS

This is a retrospective study over 8-year duration in which all the breast FNABs performed in our institution were recategorized in accordance to the IAC Yokohama reporting system. Kappa coefficient was used to evaluate the agreement between the proposed cytological category and corresponding histological diagnosis, with the level of significance set at 5%. Cyto-histopathological correlation and its diagnostic performance were also assessed.

RESULTS

A total of 1136 breast FNABs were analyzed, including 31 repeat FNABs. Of these, 521 (47.1%) cases had matched histopathological results. Respective ROM for each category was: "insufficient" 13.6%, "benign" 0.4%, "atypical" 25.0%, "suspicious" 85.7%, and "malignant" 100%. There was substantial agreement (κ=0.757) between cytology and histopathological results. Our data revealed a high-diagnostic specificity, sensitivity, positive and negative predictive value of 99.3% (95% CI: 97.6%-99.9%), 94.2% (95% CI: 87.9%-97.9%), 98.0% (95% CI: 92.5%-99.5%), 98.0% (95% CI: 96.1%-99.1%) respectively when both the "suspicious" and "malignant" cases were considered as positive tests, with area under the curve of 0.993.

CONCLUSIONS

The IAC Yokohama system is a reliable, evidence-based, and standardized reporting system that helps to facilitate communication among cytopathologists, radiologists, and surgeons toward individualized patient management.

Prospective evaluation of accuracy of fine-needle aspiration biopsy for breast lesions using the International Academy of Cytology Yokohama System for reporting breast cytopathology

BACKGROUND

Classification of breast lesions into different cytological groups can accurately be done using the International Academy of Cytology (IAC) Yokohama System for reporting breast cytopathology. Fine needle aspiration biopsy (FNAB) of breast lesions has been considered to be the primary investigation in detecting breast cancers, especially in low-cost settings. The main objective of this study was to prospectively re-confirm the diagnostic accuracy of breast FNAB using the IAC Yokohama system. Additionally, separate secondary subgroup analysis was done to confirm the accuracy of breast FNAB excluding lymph-node positive and lymphadenopathy positive tumors.

MATERIAL AND METHODS

A prospective study was done on patients undergoing biopsy of breast lesions between September 01, 2019 and November 30, 2020 (519 biopsies on 487 unique patients). Of these 519 histopathology biopsies, 505 had corresponding FNAB report of the same site. The FNAB was reported using the IAC Yokohama system and the most suitable category was allotted in every case. The rates of malignancy for each category and the accuracy of breast FNAB in diagnosing malignancy were calculated.

RESULTS

Of the total 487 patients, 120 cases were benign on histology, while 367 were malignant. The rates of malignancy in benign, atypical, suspicious and malignant categories were 5%, 25%, 71%, and 99.7%, respectively. The diagnostic accuracy of atypical, suspicious and malignant categories was calculated as 90.1%, 95.2%, and 93.3%, respectively.

CONCLUSION

The high diagnostic accuracy for each BIRADS category suggest excellent accuracy for Breast FNAB using the IAC Yokohama system.