The French National Mesothelioma Surveillance Program

OBJECTIVES

The French National Mesothelioma Surveillance Program (NMSP) was established in 1998 by the National Institute for Health Surveillance (InVS). Its objectives are to estimate the trends in mesothelioma incidence and the proportion attributable to occupational asbestos exposure, to help improve its pathology diagnosis, to assess its compensation as an occupational disease, and to contribute to research.

METHODS

The NMSP records incident pleural tumours in 21 French districts that cover a population of approximately 16 million people (a quarter of the French population). A standardised procedure of pathological and clinical diagnosis ascertainment is used. Lifetime exposure to asbestos and to other factors (man made mineral fibres, ionising radiation, SV40 virus) is reconstructed, and a case-control study was also conducted. The proportion of mesothelioma compensated as an occupational disease was assessed.

RESULTS

Depending on the hypothesis, the estimated number of incident cases in 1998 ranged from 660 to 761 (women: 127 to 146; men: 533 to 615). Among men, the industries with the highest risks of mesothelioma are construction and ship repair, asbestos industry, and manufacture of metal construction materials; the occupations at highest risk are plumbers, pipe-fitters, and sheet-metal workers. The attributable risk fraction for occupational asbestos exposure in men was 83.2% (95% CI 76.8 to 89.6). The initial pathologist's diagnosis was confirmed in 67% of cases, ruled out in 13%, and left uncertain in the others; for half of the latter, the clinical findings supported a mesothelioma diagnosis. In all, 62% applied for designation of an occupational disease, and 91% of these were receiving workers' compensation.

CONCLUSIONS

The NMSP is a large scale epidemiological surveillance system with several original aspects, providing important information to improve the knowledge of malignant pleural mesothelioma, such as monitoring the evolution of its incidence, of high risk occupations and economic sectors, and improving pathology techniques.

Pharmacokinetics of intrapleural cisplatin for the treatment of malignant pleural effusions

We determined the toxicity and pharmacokinetics of high-dose intrapleural cisplatin (CDDP) as a treatment of malignant pleural effusions (MPE). Fourteen patients with MPE were enrolled in this study. After complete drainage of the fluid, a catheter was inserted into the pleural cavity during a thoracoscopy. CDDP (300 mg) was administered via the catheter in a 6-h infusion. Peak levels, the areas under the concentration curve (AUC), and drug half-lives were measured in pleural fluid and plasma samples collected at 0 (baseline), 6, and 24 h as well as 4, 14, and 21 days after intrapleural administration. The dosage of CDDP ranged from 153 to 203 mg/m2. The time interval between infusion was prolonged until a maximum of 109 days. Only 7/40 infusions were associated with adverse effects in 4 patients (18%). Residual concentrations in pleural fluid (0.66+/-0.07 microgram /ml) were three-fold higher than in plasma (0.13+/-0.07 microgram/ml). In pleural fluid, maximal concentration (Cmax) varied from 19 to 900 microgram/ml and in plasma from 0.34 to 3.65 microgram/ml. AUC in plasma during the three courses was 112+/-49 microgram/ml/d. The T1/2 was 31+/-33 days higher than that previously reported after intravenous administration (8-15 days). Although intrapleural CDDP has the potential advantage of treating the underlying malignancy in addition to controlling the malignant effusion with a good tolerance, it cannot be recommended for the standard control of malignant pleural effusion. Indeed we observed a great variability of intrapleural CDDP concentration depending on the extent of pleural invasion and plasma diffusion. Further studies are needed to determine the value of high-dose intrapleural CDDP for the treatment of MPE.

[Endoscopic diagnosis of mesothelioma]

Mesothelioma is a rare disease but its incidence is rising. Diagnosis is still difficult but has been improved by immunohistochemical techniques and panels of pathologists. At the present time thoracoscopy is the most sensitive method for diagnosis of mesothelioma and a good alternative to thoracotomy. The main indication for thoracoscopy is unexplained pleurisy that cannot be diagnosed by needle biopsy. Thoracoscopy allows diagnosis in 95% of cases. Pleural ultrasound can be useful for diagnosis of limited pleurisy without multiple radiation exposure. Thoracoscopy is usually performed under light general anesthesia using a rigid endoscopic system. If possible, pneumothorax should be induced the day before the procedure to allow better assessment of the entry route and prevent adherences or symphysis. Tolerance of thoracoscopy is excellent. Thoracoscopy allows not only complete visualization of the pleural cavity including the diaphragmatic visceral pleura and the lung but also multiple biopsies. In early stage disease, thoracoscopy permits distinction of patients with stage Ia (involvement confined either the parietal or diaphragmatic pleura and purely inflammatory aspect in 50% of cases) from patients with stage Ib (involvement of the visceral pleura). Median survival is 28.3 months for stage Ia versus 10 months for stage Ib. Endoscopic observation enables accurate staging of tumor involvement which is an important prognostic finding and is an essential technique for early diagnosis of mesothelioma.

[Disseminated histoplasmosis caused by Histoplasma capsulatum with cerebral involvement occurring 13 years after the primary infection]

A 49-year-old man with disseminated histoplasmosis (pulmonary and central nervous system involvement) successfully treated with ketoconazole and fluconazole combination is reported. Histoplasma capsulatum infection of the central nervous system is extremely rare in France partly because the organism is not endemic. Oral treatment with newer triazoles may be useful for central nervous system histoplasmosis, but additional information is needed to establish their effectiveness.

[Mucoepidermoid bronchial tumor with an unusual radiologic presentation]

We report a case of low-grade malignant mucoepidermoid bronchial tumor in a 21-year-old woman who presented with hemoptysis. There was a striking radiological presentation with a unilateral clear radiograph. Lung scintigraphy demonstrated perturbed ventilation and perfusion of the left lung. Pulmonary angiography only showed diminished peripheral vascularization. The main vessels were clear. These anomalies fit the radiological category of air trapping accompanied by probably hypoxic pulmonary vasoconstriction. Mucoepidermoid tumors account for only 0.5-1% of all primary lung tumors. They are found in adults as well as in children. There are two clear-cut histological forms with very different prognosis. The tumors of high-grade malignancy are considered as undifferentiated carcinomas and should be treated as such. The prognosis is much better for tumors of low-grade malignancy and current treatment is surgical in the absence of recurrence after isolated endoscopic treatment.

Malignant pleural mesothelioma

The incidence of malignant pleural mesothelioma (MPM) has risen for some decades and is expected to peak between 2010 and 2020. Up to now, no single treatment has been proven to be effective and death usually occurs within about 12-17 months after diagnosis. Perhaps because of this poor prognosis, early screening has incited little interest. However, certain forms may have a better prognosis when diagnosed early and treated by multimodal therapy or intrapleural immunotherapy. Diagnosis depends foremost on histological analysis of samples obtained by thoracoscopy. This procedure allows the best staging of the pleural cavity with an attempt to detect visceral pleural involvement, which is one of the most important prognostic factors. Although radiotherapy seems necessary and is efficient in preventing the malignant seeding after diagnostic procedures in patients, there has been no randomized phase III study showing the superiority of any treatment compared with another. However, for the early-stage disease (stage I) a logical therapeutic approach seems to be neoadjuvant intrapleural treatment using cytokines. For more advanced disease (stages II and III) resectability should be discussed with the thoracic surgeons and a multimodal treatment combining surgery, radiotherapy and chemotherapy should be proposed for a randomized controlled study. Palliative treatment is indicated for stage IV. In any case, each patient should be enrolled in a clinical trial.

[Malignant mesothelioma. Diagnosis and treatment]

In over 90% of cases, mesothelioma initially presents as a banal pleural effusion, contributing no orientation to the diagnosis. The pleural fluid can even disappear after initial puncture. For early diagnosis, simple puncture, with or without biopsy, does not suffice. Thoracoscopy is 98% diagnostic. The course depends on the stage, the histological type and the general status. A new international TNM classification has been proposed to allow comparison of series and to choose a treatment appropriate to the stade: at stage I, intrapleural, local immuno-chemotherapy treatment gives good results; at stages II and III, surgery followed by radiation therapy are indicated; at stage IV, symptomatic treatment alone is justified.

Cell populations in the lesion of human cutaneous leishmaniasis: a light microscopical, immunohistochemical and ultrastructural study

To characterize the in situ cellular immune response in localized cutaneous leishmaniasis (LCL), the authors studied frozen skin biopsies from 50 patients with LCL due to Leishmania braziliensis guyanensis. A panel of 31 monoclonal antibodies was used, which defined the number and distribution of inflammatory cell subsets. Skin inflammatory infiltrates were composed of T cells (with a local CD4/CD8 ratio of 1.05 +/- 0.7 vs 1.48 +/- 0.3 in peripheral blood), macrophages and a smaller number of B cells, natural killer cells and granulocytes. Most of the T cells expressed activation markers (interleukin-2 and transferrin receptors, HLA-DR+) and an increase in T-cell-receptor gamma delta expression was noted. Analysis of the CD4+ subpopulations with newly available reagents showed that helper T cells (CD4+CD45RO+) exceeded the suppressor/inducer subset (CD4+CD45RA+) by 1.4:1. There were no differences between local immune variables from patients with primary infection (45 patients) and those with recurrence (5). In 7 patients, biopsies were analysed before and 1 month after specific treatment, and did not show significant differences except for a small increase of dermal CD1a+ (Langerhans) cells/mm2. The observed pattern of cellular skin infiltration suggests an immune-mediated tissue injury including T-cell-mediated cytotoxicity and delayed hypersensitivity reactions in addition to direct parasitic action.

Matrix remodelling and fibroblast phenotype in early lesions of human cutaneous leishmaniasis

The connective matrix participates directly in early pathological events observed in the cutaneous lesion of leishmaniasis, due to Leishmania braziliensis guyanensis. A sample of 19 skin biopsies was examined by light and electron microscopy, in order to identify the matrix components (collagen isotypes I to IV, elastin and membrane associated proteins) of the dermal infiltrate, and the pattern of organization of the reparative connective matrix. An extensive remodelling process of apparently parasite-independent nature involves different fibroblast sub-populations. The original organization of this immune-mediated lesion offers a rare opportunity to study in situ the local inflammatory mediators inducing the activation of fibroblasts and macrophages.