Management

Mesothelioma spreads extensively through the pleural space and invades adjacent structures (lung, heart, spinal cord, chest wall). Symptoms are due to accompanying pleural effusion, local invasion, sequestration of blood from the lung by the tumour, and from metastatic disease. Virtually all patients are incurable and treatment is directed against symptoms. A very small minority with smaller tumours may be potentially resectable.

Localised Disease

A very small number of patients with limited involvement are candidates for aggressive combined modality therapy. These are patients able to tolerate a pneumonectomy, with favourable histology (not sarcomatoid), and without invasion of the heart, great vessels or other adjacent organs. Adjuvant radiotherapy is not indicated except to drain sites. Adjuvant chemotherapy is sometimes recommended although there is a paucity of clinical data.

General management

Surgery is the first step in most patients. Surgery allows diagnosis and treatment of the pleural effusion with pleurodesis. The extent of surgical resection varies:

  • Pleurodesis (typically a palliative procedure)
  • Parietal Pleurectomy and decortication (increased duration of response)
  • Radical Extrapleural Pneumonectomy (EPP) provides the only real chance at cure but is used in very selected patients. It has a high mortality rate even in tertiary centres. This treatment is often followed by radiotherapy (see below) which may improve local control, and systemic therapy which may reduce the rates of distant recurrence.

About 10% of patients will undergo seeding of the thoracoscopy or thoracotomy scars. Adjuvant radiotherapy to prevent this is controversial; an initial randomised trial in 1995 was compelling but later randomised trials were not significant. The typical dose is 21 Gy in 3 fractions. Radiotherapy can also palliate metastatic deposits.
Chemotherapy provides the only real method for increasing median survival. Cisplatin + pemetrexed is the most popular combination and improves median survival for a few months.

Radiotherapy

Radiotherapy is rarely used in the management of mesothelioma but may have a role in select circumstances.

Primary Radiotherapy

Although this is advocated in some centres, the difficulties in treating the entire pleural surface while maintaining safe levels of lung dosage and accounting for organ motion makes this treatment very rarely employed.

Adjuvant Radiotherapy

Radiotherapy may have a role in patients who were treated with pleurectomy/decortication or EPP.

  • There are several case series reporting radiotherapy outcomes after pleurectomy/decortication. Radiation pneumonitis occurs is > 10% of patients and survival is about 12 months.
  • There is more data supporting the use of radiotherapy following EPP. Large case series demonstrate improved local control compared to historical controls.

Dose is typically 50 Gy in 25 fractions. Dose to the in situ contralateral lung should be kept below 10 Gy mean. Any sites of macroscopic disease need to be irradiated to 60 Gy.
Target volume definition is difficult after EPP due to changes in anatomy. It is essential to cover the ipsilateral side of the mediastinum, the pericardium, the neodiaphargm, and the previous extent of the diaphragm prior to surgery.


Links