Sarot first described the technique of extrapleural pneumonectomy (EPP) for the treatment of tuberculous empyema in 1949. Since the late 1970s, EPP has been performed almost exclusively for malignant pleural mesothelioma (MPM). Early series reported high perioperative morbidity and mortality rates. However, with improvements in patient selection, intraoperative management, and postoperative care, the morbidity, hospital stay, and mortality associated with EPP have been reduced substantially.
Step 1
Surgical Anatomy
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In traditional pneumonectomy, only the diseased lung is removed. In an EPP, the lung, parietal pleura, and a part of the diaphragm are removed.
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The anatomic location, extent, and histology subtype of MPM determine whether a patient should undergo an EPP.
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Several staging systems have been developed for MPM. The first and most widely used was developed by Butchart in 1976. In 1994, a tumor, node, metastasis (TNM)-based system was created by the International Mesothelioma Interest Group (IMIG). This system provides TNM descriptors and stage classifications. The most recent staging system (Brigham staging system) is based on analysis of more than 180 patients treated for MPM at the Dana-Farber Cancer Institute. This system considers resectability, tumor histology, and nodal status ( Table 10-1 ).
Table 10-1
Revised Staging System for Malignant Pleural Mesothelioma
STAGE
DEFINITION
I
Disease completely resected within the parietal pleural capsule (pleura, lung, pericardium, diaphragm, or chest wall containing previous biopsy sites) without lymph node involvement
II
All of stage I with positive resection margins or intrapleural (N1 or N2) lymph node involvement
III
Local extension into the mediastinum, or chest wall, or through the diaphragm or peritoneum, or extrapleural or contralateral (N3) lymph node involvement
IV
Distant metastatic disease
From Sugarbaker DJ, Flores RM, Jaklitsch MT, et al. Resection margins, extrapleural nodal status, and cell type determine postoperative long-term survival in trimodality therapy of malignant pleural mesothelioma: Results in 183 patients. J Thorac Cardiovasc Surg 1999;117(1):54-63; discussion 63-65. Table II.
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It is essential to accurately stage disease before performing an EPP. Only patients with early-stage resectable disease should undergo EPP; patients with nodal disease (mediastinal or extrapleural) are not candidates.
Step 2
Preoperative Considerations
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In MPM, after tumor stage, tumor histology is the single most important factor influencing survival. Epithelial cell type, the most common histology, confers the best prognosis; sarcomatous and mixed histologies are more aggressive; and desmoplastic MPM, the rarest subtype, is the deadliest. Most centers now operate only on patients with epithelial MPM because of the poor long-term survival after EPP for the other subtypes.
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Radiologic evaluation is essential to determine whether a patient with MPM has potentially resectable disease. Posteroanterior and lateral chest radiograph, computed tomography (CT) scan of the chest and upper abdomen, and magnetic resonance imaging (MRI) of the chest have been the most widely used modalities. CT scan provides an estimate of tumor burden and extent of tumor both locally and distantly. MRI can supplement the CT scan for detection of tumor extension into the mediastinum or the abdomen. More recently, positron emission tomography (PET) has been used to determine whether a patient has early resectable disease based on no evidence of contralateral disease or distant metastasis. Early results are promising.
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Other diagnostic modalities, such as minimally invasive procedures, also may be used to determine whether a patient can undergo an EPP. Transesophageal echocardiography can be used to assess mediastinal involvement, especially of the heart or vena cava, and to perform fine-needle aspiration of inferior mediastinal lymph nodes. Transthoracic needle aspiration via CT also can be performed to exclude extrapleural lymph node involvement (internal mammary lymph nodes). Mediastinoscopy is used frequently to determine nodal involvement if mediastinal lymph nodes (N2) are larger than 1.0 cm in diameter. Laparoscopic examination also can be used to identify transdiaphragmatic involvement that would preclude resection.
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For a patient to be considered for an EPP, the patient should have a normal performance status. Pulmonary function tests, especially forced expiratory volume in the first second of expiration (FEV 1 ) and forced vital capacity (FVC), are used to determine whether a patient can tolerate an EPP. For patients in whom a predicted postoperative FEV 1 is less than 1 L, a quantitative perfusion scan is useful to predict postoperative lung function after EPP. Arterial blood gases are obtained to rule out baseline hypoxia or hypercapnia. Two-dimensional dobutamine echocardiography is necessary to rule out ventricular dysfunction (ejection fraction <40%), significant coronary artery disease, and pulmonary hypertension (mean pulmonary artery pressure >30 mm Hg) that may increase perioperative risks. An agitated saline study also is performed to determine whether a patent foramen ovale is present that might result in a significant right-to-left shunt after EPP. Selection criteria are summarized in Box 10-1 .
BOX 10-1
Selection Criteria
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Performance status 0-1
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Predicted postoperative FEV 1 >1.0 L
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Room air Pa o 2 >65 mm Hg
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Room air Pa co 2 <45 mm Hg
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Ejection fraction >40%
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Mean pulmonary artery pressure <30 mm Hg
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Epithelial histology
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No N2 or extrapleural lymph node involvement
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No distant or contralateral disease
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Ability to complete a trimodality treatment program
FEV 1 , forced expiratory volume in the first second of expiration; Pa co 2 , partial pressure of carbon dioxide, arterial; Pa o 2 , partial pressure of oxygen, arterial.
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Thoracoscopy has become the diagnostic procedure of choice, with a yield of greater than 95% for MPM. Talc pleurodesis (aerosolized 5 g) is usually performed at the time of the thoracoscopic pleural biopsy to prevent reaccumulation of a symptomatic pleural effusion. The talc pleurodesis facilitates extrapleural dissection at the time of EPP and also may prevent intraoperative spillage of malignant cells that could increase the risk of local recurrence. A single thoracoscopic access incision ( Fig. 10-1A ) is usually placed either in the fifth or eighth intercostal space. The eighth intercostal access incision is preferred because it can be incorporated into a utility thoracotomy incision, if necessary, at the time of EPP to facilitate resection and reconstruction of the diaphragm. The location of these incisions is important so that they can be incorporated into standard thoracotomy incisions at the time of the EPP.
