DIFFUSE MALIGNANT MESOTHELIOMA

GENERAL THORACIC SURGERY

CHAPTER 65

Diffuse malignant pleural mesothelioma

• Uncommon and lethal cancer.

• Currently no standard treatment.

• Asbestos exposure is major risk factors.

• Important for thoracic surgeons to be knowledgeable about mesothilioma – Because they are often called on to make the diagnosis and to recommend treatment.

Epidemiology — Asbestos

• Asbestos belongs to the family of silicate fiber.

• Include two mineralogical groups:

Amphibole and Serpentine.

Amphibole fibers

• Narrow and straight fibers.

• Migrate through the lymphatics of pulmonary parenchyma and accumulate in interstitial space and subpleural region.

• Crocidolite asbestos （ blue asbestos ） -- The most associate with malignant mesothelioma.

Serpentine fibers

• Large, curly shaped fiber.

• do Not travel beyond the major airways.

• Chrysotile （ white asbestos, the only member of Serpentin ） -- More associate with lung cancer.

Diffuse malignant pleural mesothelioma

• Peak age—6th decade.

• Men.

• Long latency period （ at least 20 years ） .

• Incidence—men 15/million, women 3/million.

• Histology—Table 65-2.

Clinical presentation

• Nonspecific,

Chest pain, dyspnea, pleural effusion, pericardial effusion, weight loss, cough, anorexia, weakness, fever, hemoptysis.

• Horner’s syndrome.

• Spontaneous pneumothorax.

Clinical presentation

• Abnormal ECG– Sinus tachycardia (42%).

• Echocardiographic findings.

• No specific tumor marker.

• Rise serum hyaluronan.

• CA-125 (20%).

Radiographic appearance

• Chest-x ray— Variable and related to stage of tumor. • Large pleural effusion, pleural thickening, pleural-

based mass. • Encasement of lung and obliteration of pleural space. • Involve pericardium and pericardial effusion. • Chest wall invasion, invasion through diaphragm. • CT— Most accurate noninvasive way to stage. • PET scan.

Diagnosis

• Thoracentesis, cytology （ positive rate 30-50% ） . • Percutaneous pleural biopsy. • Thoracoscopy. • Open pleural biopsy. • AVOID Exploratory thoracotomy.• Bronchoscopy. • Meidastinoscopy. • Bone scans.

Staging

• Not an accurate, universally accepted staging system.

• Butchart (1976). Table 65-3.

• TNM system. Table 65-4.

• Liver is the most common site of distal metastasis, the contralateral lung is second.

Treatment

• Patient with malignant mesothelioma face a dual problem— Control of the locoregional tumor throughout the course of their disease, prevention of distant metastases as late manifestation of their cancer.

• Choice of treatment – Location and extent of he tumor, the general medical condition of patient.

• Surgery, radiation, chemotherapy, immunotherapy, supportive care.

Radiation therapy

• Difficult to evaluate the success of radiation therapy as the only treatment.

• Usually given in conjunction with surgical resection or chemotherapy.

• Limited by the volume of primary tumor that invole entire hemithorax, proximity of the tumor to many vital structures that intolerant high doses of radiation.

• 4500 cGy. • Adjuvant treatment after surgical resection of gross

tumor.

Chemotherapy

• Table 65-5.

• Combination treatment. Table 65-6.

• Response rate 30-40%

Immunotherapy

• Interferon– As antiproliferative effect on mesothelioma cell line.

• Human interferon-α-2a combined with mitomycin C.

• Interferon-γ – As an intrapleural treatment in early-stage diaseas （ 40x106U infused into pleural space twice weekly for 2 months ） , 56% response.

• Intrapleural interleukin 2.

Intrapleural gene therapy

• Herpessimplex virus thymidine kinase （ HSVtk ） gene– Transfer to tumor via adenovirus.

• Administration of antiviral drug– Ganciclovir– Led the tumor death.

Surgery

• Still the mainstay of treatment.

• Three operation–

(1). Extrapleural pneumonectomy.

（ pleuropneumonectomy ） (2). Pleurectomy-decortication.

(3). Palliative limited pleurectomy.

Extrapleural pneumonectomy

• En bloc resection of pleura, lung, ipsilateral hemidiaphragm, pericardium,

• Value– Controversial.

• Operative mortality 6- 30%.

• Preoperative CT, lung function, ventilation-perfusion scan, cardiac function evaluate.

Pleurectomy-decortication

• Remove all gross pleural disease, without removing underlying lung.

• Also remove hemidiaphragm and pericardium.

Palliative limited pleurectomy

• Resection parietal pleura to control pleural effusion.

• Thoracoscopy and talc poudrage — High effective in controlling effusion.