What is the difference between Fine Needle Aspiration Cytology (FNAC) and biopsy?

From the Guidelines

FNAC (Fine Needle Aspiration Cytology) and biopsy are distinct diagnostic procedures with different approaches and applications, where FNAC is a minimally invasive procedure for initial assessment, and biopsy provides more comprehensive information for final diagnosis and treatment planning. The key differences between FNAC and biopsy lie in their invasiveness, the amount of tissue sampled, and the information they provide. FNAC uses a thin needle to extract cells for cytological examination, making it quicker, less expensive, and causing minimal discomfort with virtually no scarring 1. In contrast, a biopsy involves removing larger tissue samples that preserve the architectural relationship between cells, providing more comprehensive information about the tissue structure. Biopsies can be incisional or excisional and typically require local anesthesia, potentially leaving a small scar.

Key Differences and Applications

• FNAC is excellent for initial assessment of lumps and masses, particularly in thyroid, breast, and lymph nodes, due to its minimality and low risk of complications 1.
• Biopsies, including core needle biopsies, are generally more definitive and often necessary for the final diagnosis of cancer, determining its type and stage, especially when the initial diagnosis is uncertain or when lymphoma is suspected 1.
• The choice between these procedures depends on the location of the lesion, suspected diagnosis, and the information needed for treatment planning, with core needle biopsy being preferred over surgical excision when tissue biopsy is required, due to its high sensitivity and low rate of complications 1.

Recommendations

• For patients with a neck mass deemed at increased risk for malignancy, FNAC should be performed instead of open biopsy as the initial diagnostic test 1.
• Core needle biopsy is an option after an initial inadequate or indeterminate FNA, especially when history and physical examination findings strongly suggest lymphoma, due to its higher sensitivity compared to FNA in such cases 1.
• The decision between FNAC and biopsy should prioritize the patient's safety, the potential for accurate diagnosis, and the need for comprehensive information for treatment planning, always considering the most recent and highest quality evidence available.

From the Research

Difference between Fine Needle Aspiration Cytology (FNAC) and Biopsy

• FNAC is a diagnostic procedure that involves the use of a fine needle to aspirate cells from a lesion or mass, whereas biopsy involves the removal of a larger tissue sample for examination 2, 3.
• FNAC is generally considered a safer and less invasive procedure than biopsy, with fewer complications and a lower risk of adverse events 3, 4.
• The diagnostic accuracy of FNAC and biopsy can vary depending on the type of lesion or tumor being evaluated, with FNAC being more accurate for certain types of tumors and biopsy being more accurate for others 5, 4.
• FNAC can provide rapid diagnostic information, allowing for the initiation of treatment or guiding further diagnostic investigation, whereas biopsy may provide more detailed information about the tumor, including its histological grade and subtype 2, 3.
• The use of image-guided needle procedures, such as ultrasound or MRI-guided FNAC, can improve the diagnostic accuracy of FNAC and reduce the risk of sampling errors 5, 6.

Advantages and Disadvantages of FNAC

• Advantages of FNAC include its safety, simplicity, and rapidity, as well as its low cost and minimal morbidity 2, 4.
• Disadvantages of FNAC include its limited sensitivity and specificity for certain types of tumors, as well as the potential for sampling errors and insufficient samples 3, 5.
• The use of FNAC as a first-line diagnostic procedure can reduce the need for open biopsies and facilitate further management, but it may not always provide a definitive diagnosis 4, 6.

Comparison of FNAC and Biopsy

• Studies have compared the diagnostic accuracy of FNAC and biopsy for various types of tumors, including lymphomas and soft tissue tumors 3, 5.
• The results of these studies have shown that FNAC can be an accurate and reliable diagnostic tool, but its accuracy can vary depending on the type of tumor and the expertise of the practitioner 3, 5.
• Biopsy is generally considered the gold standard for diagnosis, but FNAC can be a useful adjunct or alternative in certain situations 2, 4.