What are the steps and considerations for a successful excision procedure?

Excision Procedure: Steps and Key Considerations

Complete surgical excision with histologically negative margins is the cornerstone of successful excision procedures, with margin width, depth to fascia, and specimen orientation being the critical technical elements that determine oncologic outcomes.

Pre-Excision Planning

Patient Assessment and Imaging

• Obtain high-quality cross-sectional imaging (CT or MRI with and without contrast) to assess the lesion's extent, define relevant anatomy, and evaluate surrounding structures 1
• For suspicious scalp or skin lesions, clinical examination should identify the lesion's borders, depth, and relationship to underlying structures 2
• Preoperative assessment must focus on cardiac and pulmonary risk factors, functional capacity, and comorbidities that affect perioperative morbidity 3

Biopsy Considerations

• For suspicious lesions requiring diagnosis: Excisional biopsy is preferred over shave or punch biopsy, as it allows complete histological assessment including margins 2
• The diagnostic biopsy should include the whole tumor with 2-5 mm clinical margin and extend to include subcutaneous fat 2
• Shave and punch biopsies make pathological staging impossible and should be avoided for suspicious lesions 2

Surgical Technique

Margin Selection Based on Pathology

For Melanoma (most evidence-based):

• In situ melanoma: 2-5 mm clinical margins to achieve complete histological excision 1
• <1 mm Breslow thickness: 1 cm margins (narrower may be safe for <0.75 mm) 1
• 1-2 mm thickness: 1-2 cm margins 1
• 2.1-4 mm thickness: 2 cm margins preferred (2-3 cm acceptable) 1
• >4 mm thickness: 2-3 cm margins 1

For Basal Cell Carcinoma:

• Low-risk primary BCC requires 4 mm clinical margins for >95% complete removal with standard excision 4
• High-risk BCC requires Mohs micrographic surgery or wider margins with complete margin assessment 4

For Other Malignancies:

• GIST: Achieve R0 resection (≥1 mm margin) with no dissection of clinically negative lymph nodes 1
• Penile cancer: Ensure distance from tumor to margin is ≥1 mm, as local recurrence increases considerably when <1 mm 1

Depth of Excision

• Standard depth: Excision should extend to muscle fascia or deeper for melanoma, with no evidence supporting alteration of this approach 1
• For scalp lesions: Include subcutaneous fat to ensure adequate depth for histopathological assessment and accurate Breslow thickness measurement 2
• Critical warning: If subcutaneous fat is reached during curettage procedures, abandon the procedure and perform surgical excision instead—the curette cannot distinguish tumor from soft adipose tissue 4

Specimen Handling

• Orient the specimen using sutures (e.g., short suture superior, long suture lateral) to allow identification of margins if re-excision is needed 1
• Perform specimen radiography for non-palpable lesions to confirm removal of the target lesion 1
• Ink all margins immediately after excision to allow pathologic assessment 1
• Serial transverse slicing at approximately 2 mm intervals for adequate histological sampling 2

Intraoperative Margin Assessment

• Frozen section analysis is helpful in cases of doubt but routine use is not recommended 1
• For breast conservation, assess margins in the operating room before closure so additional tissue can be removed if necessary 1
• The endpoint for curettage-based procedures is determined by feeling firm, normal dermis versus soft tumor tissue 4

Critical Contraindications and Pitfalls

Absolute Contraindications for Electrodesiccation & Curettage

• Terminal hair-bearing areas (scalp, beard, pubic, axillary regions) are absolutely contraindicated due to risk of follicular tumor extension that the curette cannot detect 4
• ED&C should only be used for properly selected low-risk tumors in non-terminal hair-bearing locations 4

Common Pitfalls to Avoid

• Inadequate margins: Account for 20% tissue shrinkage when confirming adequacy of excision on histology 1
• Wrong surgical approach: Continuous incision from breast to axilla results in unnecessary deformity; use separate incisions 1
• Nerve injury: Preserve long thoracic nerve, thoracodorsal nerve, and medial pectoral nerve during axillary procedures 1
• Understaging risk: Incisional biopsy followed by ablation carries higher risk of understaging versus complete resection 1

Multidisciplinary Decision-Making

When to Involve the MDT

• All patients with melanoma stage IB and higher should be referred to a specialist skin cancer multidisciplinary team before treatment 1
• The final decision about margin size should be made by the MDT after discussion with the patient, considering functional and cosmetic implications 1
• For GIST, surgery should be performed by a subspecialty surgeon fully trained in radical anatomic site-specific cancer surgery, linked to a specialist sarcoma centre 1

Neoadjuvant Therapy Considerations

• For GIST >5 cm or challenging locations with imatinib-amenable mutations, neoadjuvant treatment may facilitate surgery and reduce extent of multi-visceral resection 1
• For penile cancer T3 disease, induction chemotherapy offers ability to downstage disease (57% objective response rate for taxane-platinum combinations) 1

Postoperative Pathology Requirements

The pathology report must include 2:

• Site and type of procedure
• Macroscopic appearance and dimensions
• Presence of ulceration
• Margin status (lateral and deep)
• Breslow thickness (for melanoma)
• Histologic subtype and grade