Surgery
The only curative treatment is removal of the affected pleura and underlying lung (radical pleura – pneumonectomy) often followed by radiotherapy and chemotherapy. This aggressive approach is only suitable when people are fit enough and with limited enough disease.
Chemotherapy
Recent studies have shown that in selected patients (fit ones), chemotherapy can cause the tumour to shrink in size (partial response) and also improve symptoms. There has been no placebo conrolled trials that prove that chemotherapy improves survival. The MSO Trial is currently trying to answer this question.
Radiotherapy
Radiotherapy is used in 2 contexts. After pleural fluid has been aspirated it is common for the tumour to track up the needle track and produce a hard lump under the skin. If the area of previous aspirations is eradicated within 4 weeks, the development of such a lump can be prevented. The other role of radiotherapy is for palliation of symptoms such a pain.
Control of fluid (Pleural Effusion)
The pleural effusion associated with mesothelioma caused breathlessness. This can simply be treated by inserting a needle and tapping off up to 2 litres of fluid (pleural aspiration). The problem is that the fluid tends to recur (within weeks – days) and the amount of fluid that can be removed is often limited by pain or coughing during the procedure. Amore long lasting solution is to stick up the pleural cavity and thus obliterate the space so that no more fluid can collect – this is called a pleurodesis. It can be performed by a chest physician, who inserts a chest drain under local anaesthetic, or at the Regional cardiothoracic Surgical Centre under general anaesthetic. Both require a spell as an impatient. Success rates vary but tend to be higher with surgical intervention.
Pain Control
The pleura are richly supplied with pain nerve endings and pain is a common symptom. It often requires a combination of different pain killers. Other interventions sometimes include TENS (transcutaneous electric nerve stimulation) or nerve block.
Dr Tim Peel—Consultant in general and respiratory medicine and palliative medicine. HIs particular interest is in lung cancer and mesothelioma.
Further Surgery Information
Biopsy and pleurodesis
Although a diagnosis can be made by a syringe and needle, a more invasive procedure is often required to obtain direct tissue from the pleura; this is often done with the aid of a camera through a single small (1 inch) incision on the side of the chest-the fluid around the lung can be drained out, biopsies taken, and if the lung can expand, it can be lightly coated with about 5 gram of talc to help it to stick to the inside of the chest. In about 80% of cases, this gets rid of most of the fluid. Most patients stay in hospital about 4 days for this procedure.
Decortication
This is an operation to remove the bulk of the tumour, leaving the lung intact. Its primary aim is to get rid of the fluid and thereby relieve the symptoms of breathlessness and possibly pain. It usually requires a cutting operation between the ribs, then the diseased pleura is stripped off the inner chest wall and lung. The main principle is to get into the layer between the diseased and normal tissue, in a similar way to removing the peel from an orange. Some pleura cannot be removed safely in this manner and is left behind: the operation should not be regarded as potentially curative.
Pleuropneumonectomy
Only the fittest patient with the most favourable type of disease (epithelioid) can be considered for this type of surgery. It is only done in a few centres in the UK. The first major series of this type of operations were done in Shotley Bridge hospital near Durham in the 1970’s and lead to one of the staging systems that are used to assess extent of disease. It was associated with a high risk of death post operatively (30%) but the technique has been refined and the death rate is more in the range of 5-10%.
The patient is fully investigated with CT and MRI scans as mentioned and other tests are done to assess fitness for surgery in particular looking at the heart reserve and how strong the remaining lung might be. Most patients will get a small preliminary operation of biopsy (see Biopsy and pleurodesis above); and even a second small procedure called mediastinoscopy to check that glands behind the breastbone are not involved. The latter again is done through a small incision and can be done as a day case.
If all these tests are satisfactory the operation of pleuropneumonectomy can go ahead. Again, there is a cutting operation between the ribs (a thoracotomy), but this time the lung and the chest wall lining are removed as a single block. Included in the block is about half of the bag that surrounds the heart (the pericardium) and the breathing muscle between the chest and the abdomen –the diaphragm. Special plastic sheeting is used to reconstruct these two areas.
Pleuropneumonectomy is an extensive operation, whose intent is to cure the patient of their tumour. It takes an experienced operator 4-5 hours to perform. In addition there are complications to watch out for in the postoperative period such as breathing failure and infection. In an uncomplicated patient a hospital stay of about 7 days would be the average. The best results with this operation have been reported from Boston, USA. Under very favourable circumstances, 2 out of every 5 patients undergoing this surgery can still be alive at 5 years. These patients in the series had other forms of treatment too such as chemotherapy and radiotherapy-operation alone is probably not worthwhile.
Sion Barnard—Thoracic surgeon Newcastle upon Tyne Freeman Hospital
Cryoablation
Management of mesothelioma has been among the most challenging of cancer therapy. Most decisive factor in survival remains stage at diagnosis and type of mesothelioma, with epitheloid type having better survival compared to sarcomatous type. Chemotherapy has shown little success in increasing survival.
Although not curative, best results to improve survival comes from patients surviving surgery namely pleurectomy (decortication) or extrapleural pneumonectomy, in combination with chemotherapy and radiotherapy. Both the surgical procedures are associated with morbidity and mortality and require expertise such that only few surgeons have the stamina or dare take on these operations. Almost all patients who undergo surgery have recurrence at some point in their disease course.
Cryoablation is an alternative minimally invasive procedure used in adjunct with standard therapies described. Cryoablation uses principles of cold temperature dissipation to induce thermal injury in target tissues.
The applicators allow conduction of compressed argon gas in applicators interior hollow chambers (large needle approximately 2 mm in diameter) which in turn lead to subzero temperatures in the applicator and surrounding tissue [1], forming an ice ball (cryo zone) which will kill any cells it engulfs. Currently the maximum size of iceball attained remains at 4 cm, which limits ablating large tumors.
Although multiple applicators can be used to reach larger ice balls (with the maximum ice ball obtained by my team being 9 cm), it does come with increased risk of morbidity [2].
Currently there is handful of centers with enough expertise to use cryoablation in management of mesothelioma. The principal indications to improve survival include ablation of localized invasive tumor to make the patient eligible for surgery and ablation of tumor following recurrence. As mentioned previously almost all patients have localized recurrences and are ineligible for repeat surgery. Cryoablation can be performed on multiple lesions at a time.
Infrequently, I have ablated up to four lesions in a single ablation setting. Another set of indications for cryoablation is palliative control of pain. These tumors invade the chest wall and the ribs and can cause neurogenic and osseous pain.
Even though the survival may not increase, most of my patients have had improved quality of life after cryoablation. I have found cryoablation a safe and relatively quick method to control pain.
Finally, cryoablation has been used for focal control of tumor invading into vital organs like heart to improve quality of life or even survival. Like all procedures there are some risks involved particularly hemorrhage and damage to vital structures, which needs to be considered while selecting patients.
Mesothelioma management requires multidisciplinary, strong and individualized approach to control the tumor early in the course to improve survival or quality of life.
1. Hoffman, NE, Bischof, JC. The Cryobiology of cryosurgical injury. Urol 2002; 60(supple 2a):40-49.
2. Fereidoun Abtin MD, Carol Wu MD, Ali Golshan MD, Robert Suh MD. CT guided percutaneous cryoablation of thoracic tumors: technical feasibility, early efficacy and imaging of 27 treated tumors. Scientific session 8, #713, 2nd World congress of Thoracic Imaging and Diagnosis in Chest disease. Valencia May 30-June 2, 2
Fereidoun Abtin MD
Assistant Professor
Department of Radiology, Thoracic Section
David Geffen School of Medicine at UCLA
757 Westwood Plaza, Room 1621
Los Angeles, California 90095-1721
Tel: 310-267-8708
Fax: 310-267-3635
pager: 24918
__________
