an uncommon cancer (3% of all cancers) which is almost exclusively related to exposure to asbestos with a synergistic effect of smoking
it has a latency period of 20-50 years following exposure to asbestos
Australia has one of the highest incidences of mesothelioma in the world, largely due to its extensive use and mining of asbestos.
currently ~500 Australians die each year with cases expected to peak this decade as cases hit 18,000 by 2020.
standardized incidence in Australia per 100,000 population: 2.3 new cases in 1982 rising to 5.4 in 2007 with peak expected within the next decade
mesothelioma may affect pleura (75%), peritoneum (20%), pericardium (5%) and rarely testicles.
currently no effective therapy as it is resistant to standard anticancer treatments
median survival ~10-12 months from diagnosis but this may be prolonged with newer therapies however, the major challenge for clinicians is the palliative management of dyspnoea, pain and cancer cachexia syndrome
surgical treatments
extended survival is more likely in those with complete resections, epithelial histology and no involvement of extrapleural lymph nodes
unfortunately, the majority of patients are not suited to this.
chemotherapy
median survival appeared to increase to 12 months from 9 months when the new antifolate agent, pemetrexed, was added to cisplatin Rx but did increase adverse effects such as neutropenia (28% vs 2.3%), vomiting (13% vs 3%), etc.1)
the adverse effects were reduced by use of vitamin B12 and folate supplements, while dexamethasone is given for 3 days at the start of Rx to reduce risk of skin rash
these agents are C/I in severe renal impairment
clinical trials are underway for a variety of targeted therapies:
epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors such as erlotinib and gefitinib