Pleural Mesothelioma
Malignant pleural mesothelioma (MPM) is an aggressive tumour derived from the lining of the pleural cavity. The incidence of MPM is 10-30 per million per year in unselected male populations, and approximately 2 per million per year in female subjects. More than 80 per cent of MPMs develop in individuals with higher than background exposure to asbestos, with an incidence as high as 366/100,000 person-years in heavily exposed workers. The latent interval between first exposure to asbestos and death is very long, with a mean of 41 years and a range of 15-67 years in one series. The use of 'asbestos exposure' as predictor of mesothelioma is however unreliable as many patients are unaware of such exposure or when it occurred. Other potential causative factors of MPMs include the simian virus 40 (SV40), other environmental carcinogens such as erionite, ionising radiation and genetic factors.
The role of radiotherapy in inducing malignancy is well described but as yet the link with mesothelioma is unclear. MPMs have infrequently been reported in patients who had received radiotherapy (with or without chemotherapy) for previous non-pleural malignancy. Examples include the development of MPMs after radiation therapy for breast cancer, Hodgkin's lymphoma involving the lung and Wilm's tumour with pulmonary metastasis. MPM following chemotherapy alone for breast cancer has also been reported. Isolated cases of concurrence of MPM with breast cancer and Hodgkin's lymphoma are described.
Pleural Symptoms
- Dyspnea
- Chest Pain
- Cough
- Fatigue
- Weight Loss
- Pleural Thickening or Pleural Effusion
Diagnosis
The diagnosis of pleural malignant mesotheliomas should be actively considered in all patients presenting with effusion relating to previous malignancies regardless of asbestos history. As treatment options develop for mesothelioma early and accurate diagnosis is increasingly important and best achieved by guided CT or VATS biopsy since cytology and blind needle aspiration are of low yield and may be misleading in this context. The exposure of The diagnosis of malignant pleural mesotheliomas should be actively considered in all patients presenting with effusion relating to previous malignancies regardless of asbestos history. As treatment options develop for mesothelioma early and accurate diagnosis is increasingly important and best achieved by guided CT or VATS biopsy since cytology and blind needle aspiration are of low yield and may be misleading in this context. The exposure of asbestos particles to a radiotherapy field carries a theoretical risk of synergy, which requires further study.
