What are the different types of biopsies available for diagnosing cancer?

Types of Biopsies for Cancer Diagnosis

The primary biopsy techniques available for diagnosing cancer are fine-needle aspiration (FNA), core needle biopsy (CNB), and excisional/open biopsy, with the choice depending on the location, size, and suspected type of cancer. Each technique offers different advantages in terms of diagnostic accuracy, tissue yield, and invasiveness.

Fine-Needle Aspiration (FNA)

• Uses a small-bore needle to obtain cytologic samples
• Advantages:
  • Minimally invasive procedure
  • Low cost
  • Well-tolerated by patients
  • Can be performed in outpatient settings
  • Low risk of complications (discomfort, bruising, infection)
  • High sensitivity (up to 95%) for malignant lesions 1
• Limitations:
  • Lower yield for benign lesions (10-50%) 1
  • May require pathologists with specific expertise
  • Often needs follow-up tissue biopsy when atypia or malignancy is identified
  • Less reliable than histology in determining cell type in malignant lesions 1

Core Needle Biopsy (CNB)

• Uses a larger-bore cutting needle to remove solid cores of tissue
• Advantages:
  • Provides tissue samples of sufficient size to eliminate need for follow-up biopsy
  • Higher diagnostic accuracy than FNA for non-palpable lesions
  • Can be performed under imaging guidance (stereotactic, ultrasound, MRI)
  • Allows histological evaluation and determination of invasiveness
  • High sensitivity (97-99%) when directed by ultrasound or stereotaxis 1
  • Can determine histologic type and grade 2
  • Good concordance for estrogen and progesterone receptor status between CNB and surgical excision 2
• Limitations:
  • More invasive than FNA
  • Risks include bleeding, bruising, discomfort, and infection 1
  • May underestimate invasion in some cases 2

Excisional/Open Biopsy

• Involves surgical removal of the entire mass or suspicious area
• Advantages:
  • Most accurate diagnostic method (100% accuracy) 3
  • Provides complete histological evaluation
  • Can be both diagnostic and therapeutic in some cases
• Limitations:
  • Most invasive procedure requiring operating room and anesthesia
  • Higher risk of complications (anesthesia complications, infection, bleeding, scarring, nerve injury) 1
  • Higher cost than needle biopsies
  • Longer recovery time

Image-Guided Biopsy Techniques

• CT-guided percutaneous needle biopsy:

  • High diagnostic accuracy (90%) for nodules ≥2 cm 4
  • Technical success rates of 94-96% 4
  • Used for lesions not visible on ultrasound 4

• Ultrasound-guided biopsy:

  • Preferred for superficial or peripheral lesions 4
  • Provides real-time visualization during the procedure 4
  • Success rates increase from 74% with standard ultrasound to 100% with contrast-enhanced ultrasound 4

• Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA):

  • Recommended for mediastinal or central pulmonary lesions 4
  • Allows visualization of vascular structures to avoid complications 4
  • High sensitivity (95%) for malignant lesions 4

Biopsy Selection Based on Tumor Location

Breast Cancer

• Core needle biopsy is preferred over FNA for non-palpable lesions 1, 2
• Ultrasound or stereotactic guidance improves accuracy 1
• Vacuum-assisted biopsy facilitates collection of adequate tissue without multiple needle insertions 1
• Marker clip placement is recommended to identify the biopsy site 1

Soft Tissue Masses

• Core needle biopsy is more accurate than FNA for extremity soft tissue masses 3
• Open biopsy remains the gold standard with 100% accuracy 3
• Biopsy should be performed by an experienced surgeon or radiologist 1
• Endoscopic or image-guided needle biopsy is indicated for deep, thoracic, abdominal, or pelvic sarcomas 1

Bone Cancer

• Core needle biopsy has accuracy rates of 88-96% when adequate samples are obtained 1
• Open biopsy provides larger sample size useful for additional studies (immunohistochemistry, cytogenetics) 1
• Appropriate communication between surgeon, musculoskeletal oncologist, and pathologist is critical in planning the biopsy route 1

Neck Masses

• FNA is recommended as the initial diagnostic test for neck masses at increased risk for malignancy 1
• Core biopsy may be considered after an initial inadequate or indeterminate FNA 1
• Ultrasound-guided core biopsy has high adequacy rate (95%) and accuracy (94-96%) 1

Practical Considerations

• Most operators perform at least two passes during biopsy 1
• Coaxial technique allows multiple passes while reducing the number of pleural punctures 1
• On-site cytopathologist, when available, reduces the number of passes required and improves diagnostic accuracy 1
• For cystic masses, evaluation should continue until a diagnosis is obtained, as they may be malignant 1

Conclusion

The choice of biopsy technique should be based on the location of the lesion, suspected diagnosis, and available expertise. While FNA is less invasive and suitable for initial evaluation, core needle biopsy provides better diagnostic accuracy and more tissue for additional studies. Open biopsy remains the gold standard but is reserved for cases where less invasive methods are inconclusive or contraindicated.