Malignant mesothelioma



## Diagnosis
An occupational exposure to asbestos must be identified using a standardized questionnaire to identify an occupational history (standard). The assistance of a physician with expertise in occupational diseases can be requested (option). Previous exposure to asbestos can be recognized if pleural plaques are found on thoracic CT scan (although these are not always present).
In cases of doubt, where there is no clear history of exposure, the diagnosis can be facilitated by searching and quantifying asbestos bodies in various biological samples by light microscopy (biometrology). Baseline values have been established to determine if a pulmonary asbestos burden is greater than that of the general population (standard): q greater than one asbestos body per sputum sample q greater than one asbestos body per millilitre of bronchoalveolar lavage taken during fibroscopic bronchoscopy q greater than 1000 asbestos bodies per gram of dry pulmonary tissue (in the case of surgical lung biopsy).
The presence of asbestos bodies in smaller numbers does not exclude the possibility of previous exposure to asbestos. Asbestos fibres in broncho-alveolar lavage or lung tissue samples may be quantified using electron microscopy (option). A thoracic CT scan is the standard examination to assess tumour extent (and to evaluate response to treatment). To make a diagnosis of pleural mesothelioma, multiple biopsies (with at least 10 samples from multiple sites) of large size (greater or equal to 4 mm), including apparently healthy zones, must be taken at thoracoscopy (standard).
Exploration using video-assisted thoracoscopic surgery is an alternative to thoracoscopy (option). Transparietal biopsy of a solid mass and/or surgical biopsy should be reserved for cases where there is a contra-indication to thoracoscopy and/or videoscopic surgery (option). Surgical or video-assisted surgery is the standard for differentiating a benign organizing pleuritis from a malignant sarcomatoid mesothelioma. Frozen sections should not be done routinely but may help to confirm the presence of diagnostic material.
Immuno-histochemical studies must include as a minimum:
q for epitheloid tumors, cytokeratin (CK 5/6), EMA, calretinin Zymed and two or three negative glandular markers (CEA, CD15, BeREP4...) q for spindle cell tumours: cytokeratin, vimentin, CD34.
In cases of doubt, a histological diagnosis can be confirmed by sending tissue and clinical samples to a panel of specialized pathologists (French MESOPATH group).
In the absence of clinical symptoms or signs, a search for metastases is not useful (standard).

## Classification

## The classification system of the international mesothelioma
Interest Group is currently best adapted to a combined medicalsurgical treatment approach, but must also be correlated with the TNM classification of the International Union against Cancer (UICC).

## Prognostic factors
Three favourable prognostic factors most often identified in multivariate analyses are: q stage I or II disease (TNM or International Mesothelioma Study Group) q epithelial histology q patient performance status 0 or 1.

## Treatment
There is no standard treatment . The outcome depends more on the prognostic factors for a given patient than the therapeutic modality chosen.
Chest drain tracts and puncture sites must be routinely and prophylactically irradiated (standard).
Radical surgery as sole treatment has not been validated; it should only be undertaken within a therapeutic study.
Similarly, chemotherapy, immunotherapy alone, immunotherapy combined with chemotherapy or combined approaches Malignant mesothelioma P Ruffie 1 , M Lehmann 2 , F Galateau-Salle 3 , JL Lagrange 4 and JC Pairon 5 1 (surgery, radiotherapy, immunochemotherapy) must only be considered within therapeutic trials.
If intracavitary treatment is not planned (stages IA, IB), early pleurodesis must be undertaken.

## Internal reviewers
V Beckendorf (Centre Alexis Vautrin, Nancy) and P Rebattu (Centre Leon Berard, Lyon). Standards  there is no standard treatment as this is individualized on the basis of prognostic factors  routine prophylactic irradiation of drain sites Option the following should be done only within a clinical trial :  radical surgery  chemotherapy, immune therapy  combination approaches (surgery, radiotherapy, immunochemotherapy)

## External reviewers
Recommendation early pleurodesis is recommended if intracavitary treatment is not planned (stages IA,IB)

## Figure 1 treatment of malignant mesothelioma
[fig] J: Ameille (Hopital Raymond Poincare, Garches, C Boutin (CHU, Hopital de la Conception, Marseille), P Chahinian (Mount Sinai Medical Center, New York, USA), P Delaval (CHR de Pontchaillou, Rennes), M Ennem-Simard (Hopital du Bel Air, Thionville), MC aurand (Hopital Henri Mondor, Creteil), M Letourneux (CHU Hopital de la Cote de Nacre, Caen), Y Martinet (CHU de Brabois, Vandoeuvre-Les-Nancy), O Menard (CHU de Brabois, Vandoeuvre-Les-Nancy), C Pairon (Centre hospitalier intercommunal, Creteil), R Riou (Centre Hospitalier, Valence), A Taytard (Hopital du Haut-Leveque, Pessac), Le Treut (Centre Medical Victor Hugo, Pertuis) and P Vuillemin (Centre Saint-Thomas, Aix en Provence). [/fig]