Approximately 5% to 8% of NSCLC extends beyond the lung to invade chest wall structures.

Prevalence numbers refer to those cases with chest wall invasion that were pathologic Stage IIB (T3N0M0) or IIIA (T3N1M0; T3N2M0).

In series published over the last 10 years, the breakdown of stages in patients undergoing surgical therapy was as follows :

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  T3N0M0: 54–75% (65+/-7%)

  
  
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  T3N1M0: 10–26% (16+/-6%)

  
  
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  T3N2M0: 9–23% (16+/-6%)

In several recent series, 66% to 90% of patients were male.

The average age in more recent series was 63 years (range: 32–93).

Squamous cell carcinoma: 42% to 60% (50+/-8%)

Adenocarcinoma: 27% to 57% (39+/-11%)

Large cell carcinoma/other: 12% to 22% (16+/-6%)

Chest wall invasion may be limited to the parietal pleura only, or it may be more expansive to encompass soft tissues, including intercostals muscles and ribs. Rarely, extrathoracic muscle invasion can occur. ,

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  Parietal pleura only: 18% to 69% (37+/-18%)

  
  
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  Soft tissue invasion: 13% to 67% (38+/-22%)

  
  
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  Bony invasion: 24% to 46% (36+/-9%)

  
  
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  Very rarely, NSCLC can present as a palpable, chest wall mass.

Chest Pain : Although intuitively one might expect a high incidence of chest pain with chest wall involvement, a sizeable number of patients were pain free. For example, Burkhart and colleagues reported chest pain as a presenting symptom in only 45% of patients. Similarly, other series reported chest pain in 47% and 51% of their patients. Chest pain ranges from a vague ache to a discrete localized pain.

Other symptoms: Hemoptysis was reported in 6% in one series, whereas cough was a presenting symptom in 18% in another. In both series, 17% to 21% of patients were asymptomatic on presentation.

This is the least sensitive modality.

Pleural-based masses do not confirm invasion and should not be relied on for diagnosis.

In some cases, clear rib destruction by a contiguous mass may be evident.

As with other imaging modalities, one needs to distinguish between tumor invasion and tumor impression, in which the tumor abuts the pleura but there is no actual pleural invasion. The latter may be the case in the often reported pleural-based mass.

Pleural thickening adjacent to the mass, lengthy contact, and angulation of the mass interface are neither sensitive nor specific.

Loss of the normal extrapleural fat plane is suggestive, whereas obvious rib destruction is highly specific.

In a recent prospective study by Bandi and coworkers in 136 patients with lung cancer and possible chest wall invasion, the sensitivity of thoracic computed tomography (CT) was reported as only 42%, with the specificity at 100%. In another study, standard CT had a sensitivity of 50% and a specificity of 71%.

Improved sensitivity (70%) was reported for thin section cuts with multiplanar CT reformatting. Likewise, much improved sensitivity was reported for high-resolution CT using an algorithm for soft tissue.

Usually in patients with a tumor abutting the chest wall on CT scan, the presence of chest wall pain is a better predictor of chest wall invasion than the appearance of the scan.

Several studies have suggested that magnetic resonance imaging (MRI) may have several advantages over CT in the diagnosis of chest wall invasion.

This stems from the fact that the extrapleural fat plane can be more readily determined on MRI because of high signal intensity on T1-weighted images. Differences in signal intensity due to tumor invasion of the chest wall musculature can be appreciated on T2-weighted images.

Improved accuracy over conventional CT or MRI was recently reported using respiratory dynamic MRI in 98 patients with suspicious CT scans. Cine images assessed tumor movement along the chest wall to note the presence or absence of free movement. Following surgical and pathologic correlation, sensitivity was 100% and specificity was 83%.

A case can be made that more sophisticated testing is not usually warranted, because a localized tumor should be resected, whether or not the chest wall is invaded.

Ultrasound, using high frequency linear probes (5–7.5 MHz), may also be a useful modality, employing several of the principles reported above for other imaging modalities.

Two or more of the following criteria suggested chest wall invasion: (1) impairment of movement along the chest wall (as in the dynamic MR study above); (2) interruption of the pleural reflection; (3) tumor growth into the chest wall; and (4) invasion of the ribs.

In 136 patients who were evaluated, ultrasound had a sensitivity of 89% and a specificity of 95%.

The false-positive rate was attributed to benign adhesions noted at surgery, which limited movement with respiration.

Other: The utility of positron emission tomography (PET), PET/CT, and other modalities needs further investigation. At present, the PET scan would not appear a good test to determine chest wall invasion.

When chest wall invasion is suspected, a preoperative CT-guided needle biopsy is preferred to alternative biopsy approaches. This is because it is not desirable to cut into the tumor for diagnosis, or to cut across a tumor to separate it from the chest wall for a wedge resection.

The operation should start with video-assisted thoracic surgery for the following reasons:

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  To make sure that there is no evidence of pleural seeding

  
  
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  To determine if the tumor is indeed attached to the chest wall

  
  
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  To determine what interspace should be used to enter the chest, with an adequate margin around the tumor

  
  
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  To determine where to cut the ribs for an adequate margin around the tumor.

When to consider :

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  Chest wall reconstruction is generally indicated for cases in which more than one rib has been resected.

  
  
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  Chest wall reconstruction is not necessary for the following situations:

  
  
  
  
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    If the resection involves ribs 1 through 4 posteriorly under the scapula. If the resection includes rib 5, then reconstruction is needed because the tip of the scapula goes inside the remaining ribs.

    
    
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    If the chest wall is ulcerated or infected over the tumor, reconstruction of the chest wall with a prosthetic is not usually performed because the prosthetic material may become infected.

  
  

Types of reconstruction: prostheses and muscle/myocutaneous flaps.

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  Chest wall reconstruction can be performed using a variety of prosthetic materials or a myocutaneous flap. Use of a stabilizing prosthesis has been reported as important in decreasing the need for prolonged postoperative mechanical ventilation. However, use of only a myocutaneous flap has not resulted in respiratory compromise in our experience (i.e., the presence of a persistent flail segment postoperatively did not significantly affect rapid weaning from mechanical ventilation or produce respiratory compromise).

  
  
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  A sandwich of Marlex (a plastic mesh) and methyl methacrylate is most commonly used to reconstruct the chest wall. The combination makes a solid prosthesis for reconstruction. The methyl methacrylate comes in the form of a liquid and powder that are mixed to make a solid prosthesis in the shape of the chest wall defect. The mesh is sutured to the surrounding ribs. This sandwich is used for chest wall resections that involve the curved part of the chest or the sternum.

  
  
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  An alternative is to reconstruct without the methyl methacrylate. For this method, the following variety of materials is available: plastic mesh, absorbable polyglactin mesh, and biologic xenografts. These are used primarily when the resection involves a flat area of the chest wall, such as the anterior surface between the sternum and the anterior axillary line.

  
  
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  A myocutaneous flap is used when the chest wall resection involves a significant amount of soft tissue and especially if skin is resected.

  
  
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  A muscle flap is used if the resection includes ribs and the overlying muscle so that there is no muscle to separate the marlex/methyl methacrylate mesh from the overlying subcutaneous tissue. Usually, a single muscle is used. The choice depends on several factors including proximity, technical and anatomic feasibility of rotating it in place, and the size of defect that needs to be covered. If the sandwich is too close to the skin, an erythematous reaction in the skin commonly ensues.

  
  
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  Muscle and myocutaneous flaps may decrease the risk of infection while covering the defect and mesh.

Perioperative management is basically the same as the postoperative care for all lung resections (see chapter 23 on surgical management of lung cancer). The keys are pain relief, early ambulation, and good pulmonary toilet.

Pain control is usually administered by an epidural or a pain pump. If an epidural is too high in the chest, respiratory depression may occur, so if the resection involves the first three ribs, a pain pump is preferable.

Complications after pulmonary resection plus chest wall resection are basically the same as for other pulmonary resections. Rib resection includes resection of the intercostal nerves, so patients experience permanent paresthesias in the distribution of those nerves.

In all series :

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  Mediastinal and hilar lymph node involvement

  
  
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  Incomplete resection

In some series:

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  Depth of invasion

  
  
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  Male gender

  
  
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  Poor tumor differentiation

  
  
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  Tumor size

  
  
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  Extent of resection

  
  
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  Older age

  
  
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  Type of surgical approach

The same general principles employed in other potentially resectable cases should be used. Because of the added morbidity of a chest wall resection however, a more conservative approach is prudent and is advised for patients with limited pulmonary function. (See chapters 3 and 31 on resection in patients with limited reserve and perioperative assessment.)

A case series of en bloc resection and limited lung resection in 10 patients with poor pulmonary function (FEV ₁ <1.3 L) was reported. There was no perioperative mortality, and long term follow-up results were acceptable.

Radiation:

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  Adjuvant radiotherapy may be employed even in R0 resections. When resection margins are positive or narrow, radiation may be given in an effort to reduce local recurrence. The discovery of hilar or mediastinal adenopathy in surgical specimens will likely also prompt adjuvant chemotherapy with or without radiation therapy.

  
  
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  In 209 patients who underwent en bloc chest wall resections, adjuvant radiation therapy did not impact on the rate of local recurrence or overall survival in patients with stage IIB (T3N0) disease. In contrast, adjuvant radiation therapy did increase survival in those patients with stage IIIA disease.

  
  
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  Radiation therapy improved outcome in some series, but not in another.

Chemotherapy

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  The role of chemotherapy in patients with chest wall invasion who are pStage IIB is unclear. The number of patients with lung cancer involving the chest wall is small, so there are no randomized, prospective trials to assess the value of adjuvant chemotherapy. However, the studies do show a small benefit for adjuvant chemotherapy for stage 2 and 3 lung cancer (see chapter 24 on adjuvant and neoadjuvant chemotherapy of NSCLC). Therefore, patients with lung cancer invading the chest wall generally receive adjuvant chemotherapy.

  
  
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  There is no proven benefit for preoperative chemotherapy in patients with lung cancer invading the chest wall.