What is functional preservation through wedge resection in patients with early-stage cancers, such as lung or liver cancer?

Functional Preservation Through Wedge Resection

Wedge resection is a lung-sparing surgical technique that removes a small, peripheral portion of lung tissue containing the tumor while preserving maximum pulmonary function, primarily indicated for patients with compromised cardiopulmonary reserve, small peripheral tumors ≤2 cm (especially ground-glass opacities or minimally invasive adenocarcinomas), or those unable to tolerate more extensive anatomic resection. 1

Core Concept and Rationale

Wedge resection represents a sublobar resection that removes only the tumor-bearing portion of lung tissue without respecting anatomic boundaries of bronchopulmonary segments. 1 The fundamental goal is to achieve oncologic control while maximizing preservation of functional lung parenchyma in patients where standard lobectomy poses excessive risk. 1

Key Functional Benefits

• Reduced perioperative mortality: 1.21% for wedge resection versus 1.93% for anatomic resection in propensity-matched populations, representing a 37% mortality reduction. 2
• Lower major morbidity: 4.53% versus 8.97% for anatomic resection—a 50% reduction in major complications. 2
• Preserved pulmonary function: Particularly critical in patients with baseline FEV1 <85% predicted, where mortality benefits are most pronounced. 2
• Lung volume reduction effect: In patients with emphysema, resection of tumor within diseased lung tissue can paradoxically improve respiratory function. 1

Clinical Indications

Acceptable Use Cases

Wedge resection is appropriate for:

• Pure ground-glass opacity lesions or adenocarcinoma in situ with minimal invasion ≤2 cm. 1
• Compromised patients with limited cardiopulmonary reserve (FEV1 or DLCO <80% predicted) who cannot tolerate lobectomy. 1, 3
• Synchronous multiple primary lung cancers where combination surgery preserves function while maintaining curability. 4
• Elderly or high-risk patients where perioperative mortality around 5% is acceptable given good long-term survival. 1

Critical Limitations

Wedge resection should be used cautiously because:

• Higher local recurrence rates compared to lobectomy, particularly for solid tumors. 1
• Inferior to segmentectomy: Wedge resection lacks complete resection of lymphatic and vascular drainage basins. 1
• Histology matters: For squamous cell carcinoma, lobectomy remains superior; for adenocarcinoma, wedge resection is inferior to lobectomy while segmentectomy shows equivalent outcomes. 1
• Size restrictions: Generally reserved for tumors ≤2 cm; lobectomy remains standard for solid-appearing tumors >2 cm. 1

Technical Considerations

Surgical Margins

The minimum adequate margin remains undefined, but practical issues exist: 1

• Staple lines represent 3-5 mm of tissue not assessed histologically
• Margin determination depends on lung inflation status
• Frozen section and staple line cytology can establish negative margins intraoperatively, though validation data are limited

Approach Selection

Video-assisted thoracoscopic surgery (VATS) is preferred over open thoracotomy for wedge resection, offering: 1, 3

• Lower operative mortality
• Shorter hospital stay (typically 2 days postoperatively)
• Fewer complications
• Less postoperative pulmonary dysfunction
• Reduced postoperative pain

Preoperative Assessment Algorithm

Before proceeding with wedge resection, systematically evaluate: 1, 3

1. Pulmonary function testing: Measure FEV1 and DLCO

   • If either <80% predicted → proceed to exercise testing and split lung function
   • Calculate predicted postoperative (PPO) FEV1 and PPO DLCO
   • Ensure PPO values >40% predicted before surgery

2. Cardiac risk stratification: Use recalibrated thoracic RCRI (Revised Cardiac Risk Index) 1

3. Tumor characteristics: Confirm size ≤2 cm, peripheral location, ground-glass opacity features on CT 1

4. Lymph node assessment: Systematic nodal dissection still required (minimum 6 nodes/stations, 3 mediastinal including subcarinal) 1

Common Pitfalls to Avoid

• Do not use wedge resection for solid tumors >2 cm without compelling functional contraindications to lobectomy. 1
• Do not skip lymph node dissection—systematic nodal evaluation remains mandatory for accurate staging. 1
• Do not assume wedge equals segmentectomy—segmentectomy provides better oncologic outcomes and should be preferred when technically feasible. 1
• Do not proceed without adequate margin assessment—ensure negative frozen section margins intraoperatively. 1

Outcomes Data

In patients with synchronous multiple primary lung cancers treated with combination surgery including wedge resection, 5-year survival reaches 85.0% overall (94.9% for stage I disease), with postoperative pulmonary function reductions matching predicted values. 4 However, these perioperative benefits must be weighed against increased locoregional recurrence risk compared to anatomic resection. 2