Diseases and Disorders
Malignant Pleural Effusion
Cancer that spreads into the pleural cavity, or the space between the lung and the chest wall, can create fluid or a pleural effusion. This process can occur from lung cancer, mesothelioma, or other types of cancers. As fluid accumulates, it displaces the lung and compromises its function, making patients feel short of breath or experience chest pain.
- A tailored approach to malignant pleural effusions to maximize the chances of eradicating it
- Utilization of minimally invasive techniques to allow faster recovery and minimize hospital stay
- Availability of novel options in the treatment of difficult effusions, such as an indwelling catheter or tube that can be used to drain fluid periodically at home (PleurX®)
Mechanism of Disease
Cancer cells of many types can gain entry into the pleural cavity, and many times cause the accumulation of fluid known as a pleural effusion. This is due to cancer cells plugging the microscopic drainage sites in the pleural lining where the body can normally absorb fluid. It is also due to the direct secretion of fluid by the cancer cells themselves. As the fluid accumulates, it pushes the lung and collapses it, causing shortness of breath or chest discomfort.
Pleural effusions due to a cancer are notoriously difficult to diagnose due to the limitations of existing technology. Most commonly, a patient first undergoes a thoracentesis or drainage procedure that involves the removal of the fluid with a small needle that is inserted into the back. This fluid is examined for tumor cells, but this method is not reliable due to the dilution that occurs in large volumes of fluid. In many cases this technique results in an indeterminate or nondiagnostic outcome.
When definitive diagnosis is required, surgical exploration with the use of a small video camera inserted into the chest is the optimal technique. This is known as video-assisted thoracoscopic surgery (VATS), and is done under general anesthesia. Through a single tiny incision, the surgeon can directly inspect the pleural cavity and look for evidence of tumor cells as the cause of the effusion. A major advantage of this approach is that treatment can be done in the same setting, making the VATS procedure both diagnostic and therapeutic.
When the fluid is evacuated and the lung is able to re-expand and obliterate the pleural space, a medication can be instilled into the chest to make the lung adhere to the chest wall. This is known as pleurodesis, and essentially prevents fluid buildup and keeps the lungs from collapsing due to the effusion. There are a variety of agents that are used for this purpose, the most common being sterile talcum powder.
If the fluid is removed and lung does not re-expand, it is considered trapped. This often occurs then the tumor forms a rind on the lung and keeps it rigid and collapsed. In these situations, pleurodesis does not work effectively because there is no contact between the chest wall and the lung. An indwelling catheter or tiny tube known as the PleurX® has been an excellent option in these situations.[FIGURE] The patient can go home with this tube, which is tucked away out of sight when not in use, and can be connected to a drainage canister when needed at home to intermittently drain the effusion. This is typically done one to three times per week.
The ability to both diagnose and treat a malignant pleural effusion with the use of VATS has given excellent results to patients with this condition. In one procedure, the diagnostic shortcomings of thoracentesis are avoided, and the treatment is given under the comfort of general anesthesia. Pleurodesis has a long track record of excellent control of effusions, and most recently the use of PleurX catheters have given patients an alternative to repeated needle sticks in the back.