Multi-Modality Treatment for Mesothelioma
There is still no effective therapy for malignant pleural mesothelioma. Left untreated, the average survival time is between four to 13 months. Even with treatment, the average survival is between six to 18 months.
According to a study titled Surgical Treatment of Malignant Pleural Mesothelioma – A Review, published February 2003 in Chest, researchers noted that:
“In general, MPM (malignant pleural mesothelioma) is a disease confined to the pleural cavity for a long time before metastasizing. Therefore, focus on local treatment seems rational. Surgical resection has been considered the mainstay of treatment by some. However, surgery alone results in high recurrence rates, and the survival benefit remains questionable. In recent years, the emphasis has been on surgery combined with adjuvant therapies.”
Surgery, used as the primary treatment, in conjunction with adjuvant (secondary) treatments like radiation and chemotherapy make up what is known as multi-modality therapy. This is the current standard of care for the disease.
There are three surgical procedures currently used:
- Pleurodesis is used for the management of persistent shortness of breath that results from pleural effusion, which is the excessive accumulation of fluid in the pleura, the layers of tissue that line the lung and chest cavity. The fluid is completely drained and an irritating agent is introduced into the pleural space that will cause scar tissue to form and block the space so it will not refill with fluid. The most commonly used irritant is sterile, asbestos-free talc, administered either as a powder or slurry (talc mixed in fluid). However, if there is a bulky tumor in the pleural space or the lung is trapped by a thick visceral pleural (the part of the pleural lining covering the lung) peel of tumor, then the procedure will not be very effective.
- Pleurectomy, also called decortication, is open surgery in which the pleura and the sac surrounding the heart are stripped from the top of the lung to the diaphragm. It is considered more effective than talc pleurodesis in lessening the recurrence of fluid buildup. However, it does not increase survival time. According to a study titled Video-Assisted Thoracoscopic Pleurectomy in the Management of Malignant Pleural Effusion, published May 1995 in Chest, video-assisted thoracoscopic pleurectomy showed better results than open pleurectomy. This less invasive procedure, performed with three inch long incisions for the insertion of camera and instruments, was used in a group of 19 study participants ranging in age from 51 to 84 years old. All of them were successfully discharged from the hospital with an average postoperative stay of 5 days. After an average follow-up of 12 months, six patients died of their underlying disease. In the remaining 13 patients, two developed fluid buildup again.
- Extrapleural pneumonectomy is a complex surgical procedure involving complete removal of the disease-affected lung along with the pleura, the sac surrounding the heart, the majority of the diaphragm on the affected side and parts of the nerve the control the diaphragm’s movement. It permits the application of higher doses of radiation because the lung has been removed and it is the only surgical procedure that can be used when a thick tumor rind is blocking the pleural space. In spite of this, the procedure is associated with a high incidence of medical conditions and mortality. In a study titled Prevention, early detection, and management of complications after 328 consecutive extrapleural pneumonectomies, published July 2004 in The Journal of Thoracic and Cardiovascular Surgery, a group of 328 patients, ranging in age from 28 to 77 years old, undergoingextrapleural pneumonectomy between 1980 and 2000 were tracked.
The researchers observed that they experienced a variety of complications, the primary one being atrial fibrillation (rapid, uneven contractions in atrial chambers of the heart), seen in 145 patients. The researchers concluded that patients undergoing extrapleural pneumonectomy require extensive postoperative management so that medical conditions that arise as a result of the surgery can be found early and aggressively treated.
Once surgery is performed, patients are given secondary therapy including both radiation and chemotherapy. The best results seem to come from what is called the trimodality approach- a combination of extrapleural pneumonectomy, radiation and chemotherapy. Before the patient is permitted to undergo this type of aggressive disease management, they must first have a chest MRI of both the right and left sides of the chest so that the doctor can evaluate how much of the thoracic cavity between the lungs and the diaphragm have been affected. There is also testing to see lung function, including a ventilation/perfusion lung scan to evaluate the circulation of air and blood within the lungs for patients whose FEV1 is borderline normal. The FEV1 is the most air that can be forcefully exhaled by the patient in one second. That number is converted to a percentage of normal based on factors like age, weight and height. Finally, an echocardiogram is administered to assess how much of the thoracic cavity between the lungs has been invaded by the tumor and how well the ventricles of the heart are functioning.
Patients who are older than 55 years old may not be candidates for extrapleural pneumonectomy because of the increased rate of mortality in this patient population in the time frame between hospitalized for surgery and discharge.