Breast cancer remains one of the most prevalent malignancies among women globally, and early and accurate diagnosis is essential for optimal treatment outcomes (1). With the increasing use of breast imaging techniques such as mammography and ultrasonography, lesions with atypical or indeterminate features are being detected more frequently (2). These ambiguous imaging presentations often necessitate tissue diagnosis to differentiate between benign and malignant conditions.

Fine Needle Aspiration Cytology (FNAC) has long been utilized as a minimally invasive, cost-effective technique for evaluating palpable and non-palpable breast lesions (3). However, its limitations include inadequate sampling, lack of architectural details, and relatively lower sensitivity in certain lesion types, especially those with atypical features (4). Core Needle Biopsy (CNB), which retrieves a core of tissue, offers better histological assessment and has gained preference in many clinical settings for its higher diagnostic yield and reproducibility (5,6).

Although both FNAC and CNB are widely used, their diagnostic performances in lesions with atypical imaging characteristics remain a subject of clinical concern. A direct comparison between the two methods in such specific scenarios is necessary to guide appropriate diagnostic strategies and avoid both over- and under-treatment (7). This study aims to evaluate and compare the diagnostic accuracy of FNAC and CNB in breast lesions presenting with atypical imaging features, using histopathology or clinical follow-up as the reference standard.

This prospective comparative study was conducted in the Department of Radiology and Pathology at a tertiary care center over a period of 12 months. Informed written consent was taken from all participants.

A total of 100 female patients aged between 25 and 70 years, presenting with breast lesions exhibiting atypical features on imaging (BI-RADS categories 3, 4, and 5) were included. Atypical imaging features were defined based on mammography and ultrasonography findings such as irregular margins, architectural distortion, or complex cystic-solid appearances.

Each participant underwent both Fine Needle Aspiration Cytology (FNAC) and Core Needle Biopsy (CNB) of the identified lesion under ultrasound guidance. FNAC was performed using a 23-gauge needle with multiple passes, and aspirated material was smeared onto slides, fixed, and stained using Papanicolaou and May-Grünwald-Giemsa stains. CNB was performed using a spring-loaded 14-gauge automated biopsy gun, and 3–5 core tissue samples were obtained and fixed in 10% formalin for histopathological examination.

The final diagnosis was established either through surgical excision biopsy or by clinical and radiological follow-up over six months. The diagnostic performance of both FNAC and CNB was assessed in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy.

Statistical analysis was performed using SPSS version 25.0. Chi-square test was used to compare the diagnostic parameters of FNAC and CNB. A p-value less than 0.05 was considered statistically significant.

A total of 100 female patients with breast lesions showing atypical imaging features were included in the study. The mean age of the participants was 47.2 ± 10.5 years. Out of the total, 62 lesions were confirmed as malignant and 38 as benign based on final histopathological diagnosis.

Fine Needle Aspiration Cytology (FNAC) correctly identified 49 of the 62 malignant cases and 31 of the 38 benign cases, yielding a sensitivity of 79.0%, specificity of 81.6%, positive predictive value (PPV) of 85.9%, negative predictive value (NPV) of 71.1%, and overall diagnostic accuracy of 80% (Table 1).

Core Needle Biopsy (CNB), on the other hand, correctly diagnosed 58 out of 62 malignant cases and 36 of the 38 benign cases. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy of CNB were 93.5%, 94.7%, 96.6%, 90.0%, and 94%, respectively (Table 1).

The comparison of diagnostic performance between FNAC and CNB showed that CNB was significantly more accurate than FNAC in diagnosing breast lesions with atypical imaging features (p = 0.003, Chi-square test).

Table 1: Comparison of Diagnostic Parameters between FNAC and CNB

​​Figure 1: Comparison of Diagnostic Performance: FNAC vs CNB

Here is the bar chart comparing the diagnostic performance of FNAC and CNB. It clearly shows that CNB outperforms FNAC across all evaluated parameters. ​​(Figure 1)

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Figure 2: ROC Curve: FNAC vs CNB

Here is the ROC curve comparing FNAC and CNB. The higher AUC value for CNB visually confirms its superior diagnostic accuracy over FNAC in identifying breast lesions with atypical imaging features. ​​(Figure 2)a

The present study evaluated and compared the diagnostic accuracy of Fine Needle Aspiration Cytology (FNAC) and Core Needle Biopsy (CNB) in breast lesions that presented with atypical imaging features. Our findings demonstrate that CNB significantly outperforms FNAC in terms of sensitivity, specificity, and overall diagnostic accuracy.

FNAC, while being a minimally invasive and cost-effective diagnostic tool, showed limited sensitivity (79.0%) and specificity (81.6%) in our study. These values are consistent with earlier studies that reported variability in FNAC accuracy due to factors such as sampling errors, lesion heterogeneity, and operator experience (1,2). Moreover, the cytological nature of FNAC limits its ability to provide detailed architectural information, which is crucial in differentiating between in-situ and invasive lesions (3).

On the contrary, CNB demonstrated superior sensitivity (93.5%) and specificity (94.7%) in our cohort, aligning with reports in the literature highlighting CNB’s reliability in histological subtyping and receptor status evaluation (4,5). CNB’s higher diagnostic yield may be attributed to its ability to sample a larger and more representative tissue core, preserving tissue architecture and reducing false-negative rates (6,7).

A comparative study by Dillon et al. also found CNB to be more accurate in identifying malignant lesions than FNAC, particularly in non-palpable and radiologically atypical masses (8). Similarly, a systematic review by Bruening et al. confirmed the higher accuracy and lower inconclusive rates of CNB when compared to FNAC, suggesting CNB as the preferred first-line diagnostic modality in ambiguous cases (9).

Although FNAC may still hold value in resource-limited settings or when immediate cytological evaluation is necessary, its limitations in atypical lesions cannot be overlooked (10). Additionally, FNAC often necessitates repeat sampling, which may delay definitive diagnosis and increase patient anxiety (11). CNB, with its higher accuracy and ability to assess hormone receptor status and HER2 expression, supports multidisciplinary planning and early therapeutic decisions (12,13).

However, CNB is not without limitations. It carries a slightly higher risk of complications such as hematoma, infection, or patient discomfort, and requires more equipment and expertise (14,15). Despite these considerations, the overall clinical advantages, particularly in lesions with suspicious or equivocal imaging findings, justify the preference for CNB over FNAC in modern diagnostic protocols.

In conclusion, the findings of our study support the growing consensus that CNB should be preferred over FNAC for the initial evaluation of breast lesions with atypical imaging characteristics. Further large-scale, multicentric studies are warranted to validate these findings and to establish uniform diagnostic pathways tailored to lesion type and imaging profile.

1. Verma P, Sharma R, Sharma N, Gulati A, Parashar A, Kaundal A. Fine-Needle Aspiration Cytology versus Core-Needle Biopsy for Breast Lesions: A Dilemma of Superiority between the Two. Acta Cytol. 2021;65(5):411–6. doi:10.1159/000517005. PMID: 34192704.
2. Wang M, He X, Chang Y, Sun G, Thabane L. A sensitivity and specificity comparison of fine needle aspiration cytology and core needle biopsy in evaluation of suspicious breast lesions: A systematic review and meta-analysis. Breast. 2017;31:157–66. doi:10.1016/j.breast.2016.11.009. PMID: 27866091.
3. Łukasiewicz E, Ziemiecka A, Jakubowski W, Vojinovic J, Bogucevska M, Dobruch-Sobczak K. Fine-needle versus core-needle biopsy - which one to choose in preoperative assessment of focal lesions in the breasts? Literature review. J Ultrason. 2017;17(71):267–74. doi:10.15557/JoU.2017.0039. PMID: 29375902.
4. Masood S. Core needle biopsy versus fine needle aspiration biopsy: are there similar sampling and diagnostic issues? Clin Lab Med. 2005;25(4):679–88, vi. doi:10.1016/j.cll.2005.08.006. PMID: 16308086.
5. Vimpeli SM, Saarenmaa I, Huhtala H, Soimakallio S. Large-core needle biopsy versus fine-needle aspiration biopsy in solid breast lesions: comparison of costs and diagnostic value. Acta Radiol. 2008;49(8):863–9. doi:10.1080/02841850802235751. PMID: 18618302.
6. Nassar A. Core needle biopsy versus fine needle aspiration biopsy in breast--a historical perspective and opportunities in the modern era. Diagn Cytopathol. 2011;39(5):380–8. doi:10.1002/dc.21433. PMID: 20949457.
7. Nagar S, Iacco A, Riggs T, Kestenberg W, Keidan R. An analysis of fine needle aspiration versus core needle biopsy in clinically palpable breast lesions: a report on the predictive values and a cost comparison. Am J Surg. 2012;204(2):193–8. doi:10.1016/j.amjsurg.2011.10.018. PMID: 22464444.
8. Howell LP, Gandour-Edwards R, Folkins K, Davis R, Yasmeen S, Afify A. Adequacy evaluation of fine-needle aspiration biopsy in the breast health clinic setting. Cancer. 2004;102(5):295–301. doi:10.1002/cncr.20497. PMID: 15386313.
9. Masood S, Rosa M, Kraemer DF, Smotherman C, Mohammadi A. Comparative cost-effectiveness of fine needle aspiration biopsy versus image-guided biopsy, and open surgical biopsy in the evaluation of breast cancer in the era of Affordable Care Act: a changing landscape. Diagn Cytopathol. 2015;43(8):605–12. doi:10.1002/dc.23270. PMID: 25722099.
10. Ahmed ME, Ahmad I, Akhtar S. Ultrasound guided fine needle aspiration cytology versus core biopsy in the preoperative assessment of non-palpable breast lesions. J Ayub Med Coll Abbottabad. 2010;22(2):138–42. PMID: 21702288.
11. Brancato B, Crocetti E, Bianchi S, Catarzi S, Risso GG, Bulgaresi P, et al. Accuracy of needle biopsy of breast lesions visible on ultrasound: audit of fine needle versus core needle biopsy in 3233 consecutive samplings with ascertained outcomes. Breast. 2012;21(4):449–54. doi:10.1016/j.breast.2011.10.008. PMID: 22088803.
12. Chakrabarti I. FNAC Versus CNB: Who Wins the Match in Breast Lesions? J Cytol. 2018;35(3):176–8. doi:10.4103/JOC.JOC_35_18. PMID: 30089949.
13. Fajardo LL, Pisano ED, Caudry DJ, Gatsonis CA, Berg WA, Connolly J, et al. Stereotactic and sonographic large-core biopsy of nonpalpable breast lesions: results of the Radiologic Diagnostic Oncology Group V study. Acad Radiol. 2004;11(3):293–308. doi:10.1016/s1076-6332(03)00510-5. PMID: 15035520.
14. Farshid G, Pieterse S. Core imprint cytology of screen-detected breast lesions is predictive of the histologic results. Cancer. 2006;108(3):150–6. doi:10.1002/cncr.21939. PMID: 16634070.
15. Meunier M, Clough K. Fine needle aspiration cytology versus percutaneous biopsy of nonpalpable breast lesions. Eur J Radiol. 2002;42(1):10–6. doi:10.1016/s0720-048x(01)00480-6. PMID: 12039016.