Does thoracoscopic treatment offer any advantages over closed chest tube drainage for the management of malignant pleural effusion? This controversial question was debated by Dr. Henri Colt, Associate Professor of Medicine, the University of California, San Diego, and Dr. Carolyn Dressler, a general thoracic surgeon from Philadelphia, in a special session at the 1996 International Conference of the American Thoracic Society. In the first of a two-part report on that session, Dr. Colt presents arguments in support of the use of thoracoscopy. Dr. Dressler's remarks will be featured in a subsequent issue.
Physicians who are asked to manage patients with a malignant pleural effusion are faced with a great predicament, said Dr. Colt. Many of these patients have a short life expectancy, and any management decision will have a major impact on the quality, and possibly, the quantity of their remaining life.
Thus, the clinician needs to consider many factors before performing pleurodesis. Knowing the patient's primary neoplasm and prognosis is especially important. Whether the patient has undergone therapy previously is also relevant; many patients have had prior chemotherapy or radiation therapy. Other considerations include the patient's general health status (which may be poor) and performance status (ie, whether the patient is ambulatory or bedridden).
It may be useful to know the extent of pleural involvement, said Dr. Colt, specifically, whether the lung itself is involved or whether the neoplasm is limited to the parietal pleura, because such findings as a trapped lung may alter therapy. One cannot definitively establish the extent of pleural involvement, however, without viewing the pleural space.
A 1988 study by Sahn and Good suggested that pleural pH and glucose may be indicative of extensive disease. In patients with low pH effusions in this study, however, tetracycline(Drug information on tetracycline) pleurodesis was rarely successful using classic tube thoracostomy techniques.
"Thoracoscopy, on the other hand, is our window into the pleural space," said Dr. Colt. He believes that thoracoscopy is advantageous for patients and their families, as well as for physicians, health maintenance organizations, third-party payors, and hospitals, "because the recommendations that derive from what is seen during the thoracoscopic procedure will affect patient outcome and future management decisions."
According to Dr. Colt, thoracoscopy has the following advantages:
- The procedure is easily performed and safe.
- Thoracoscopy allows for both diagnosis and staging of disease.
- The extent of parietal pleural and/or visceral pleural involvement can be determined, as well as whether or not the lung is trapped.
- In case of malignant pleural effusion, pleurodesis by talc insufflation or even insertion of a pleurocutaneous or pleuroperitnoeal shunt can be performed immediately, if indicated.
- In some cases, thoracoscopic findings lead to modifications in medical management that may favorably alter prognosis.
A Simple, Safe Technique
Dr. Colt asserted that thoracoscopy is a simple, safe technique. It can be performed in the operating theater while the patient is under general anesthesia, with single- or double-lumen intubation and through single or multiple points of entry. However, it can also be done under local anesthesia with basic instrumentation in a specially equipped bronchoscopy or endoscopy suite.
When thoracoscopy is carried out in a patient with a suspected malignant pleural effusion, a 1-cm skin incision is made, and a 7-mm pleural trocar is placed into the pleural cavity through that small incision. A telescope can then be placed through the trocar to inspect the pleural cavity and lungs. All pleural fluid can be removed at once.
An additional advantage of this technique, said Dr. Colt, is that placement of the chest tube for pleural fluid drainage and lung reexpansion can be guided by the thoracoscope. This ensures that "the tube will be placed where you want it in a dependent area in order to ensure complete lung expansion."
When thoracoscopy reveals a completely trapped lung, one or two tubes can be placed and high pleural suction applied, which may result in complete lung expansion. If thoracoscopy is performed in an intubated patient, positive pressure can be applied to further enhance lung reexpansion. This is not possible using closed chest tube drainage alone.
With regard to safety, Dr. Colt noted that the complications that may occur when thoracoscopy is performed for other indications usually do not apply for procedures done for a malignant pleural effusion. The main concern in the latter setting, he said, is contamination with tumor cells at the point of entry of the thoracoscope. This does not happen when thoracoscopy is performed in patients with metastatic pleural carcinomatosis from breast, lung, or gastrointestinal cancers but may occur in patients with malignant mesothelioma. Although such a problem is infrequent even in patients with malignant mesothelioma, Dr. Colt treats these patients with external-beam radiation (approximately 21 Gy over 3 days), which prevents the local spread of disease through the incision sites.
Definite Role in Management
"Thoracoscopy definitely has a role in the management of patients with malignant pleural effusions and in those with lung cancer," Dr. Colt said. Many studies done in Europe and the United States have shown that thoracoscopic talc insufflation (also known as talc poudrage) has excellent results with minimal morbidity.
In addition, thoracoscopy can immediately indicate the need to place a pleural peritoneal shunt, eg, in the patient with a trapped lung. Moreover, pleurectomy or pleural abrasion techniques can be employed for pleurodesis and are almost always successful, although these procedures may be too invasive (because of increased morbidity and risk of bleeding) in a patient with substantial neoplastic involvement of the pleura.
Thoracoscopy also helps determine whether an effusion is neoplastic or paramalignant (ie, due to causes other than pleural carcinomatosis in a patient with a primary cancer in other sites), particularly when pleural fluid cytologies have been negative on prior thoracenteses. Dr. Colt added that this distinction has important ramifications for prognosis and for future treatment recommendations. Pleural cytology is positive in perhaps 40% to 80% of patients with malignant pleural effusions. Most clinicians know of cases in which pleurodesis was performed in patients with a suspected malignant pleural effusion who later were shown to have a paramalignant effusion.
In cases of negative pleural cytology, because as many as 20% of exudative effusions may go undiagnosed, it is important to recognize that one-third to one-half of these may actually be malignant. For example, Boutin et al have demonstrated the value of the thoracoscopic approach. Their work showed that thoracoscopic appearance is evocative of cancer in almost 90% of patients with effusions of unknown origin despite negative thoracentesis and negative pleural biopsy. Knowing that a patient has cancer metastatic to the pleura alters prognosis and may affect lifestyle and treatment decisions.