New national guidelines for the treatment of pleural mesothelioma reflect the significant diagnosis and management advances seen over the past decade, providing a blueprint for Australian clinicians to provide better care.

The first update to recommendations in 13 years draws on a committee of experts from across disciplines including medical oncology, radiology, respirology and surgery along with patient input [link here].

The project, supported by icare NSW and the Asbestos and the Silica Safety and Eradication Agency (ASSEA), covers best practice approaches across the full spectrum of mesothelioma care from diagnosis to palliative care and medicolegal considerations.

Associate Professor Anthony Linton, the research director at the Asbestos and Dust Diseases Research Institute, says the document recognises the new landscape faced by clinicians and patients since the last guidelines document came out in 2013.

Associate Professor Anthony Linton.

“In the diagnostic space, there has been updates to how we classify tumours histologically. We no longer call it ‘malignant mesothelioma’, just ‘mesothelioma’ as all mesotheliomas are malignant in nature. We also see a new subcategory of mesothelioma in situ,” he tells the limbic.

“For radiology, we now see an increased role of image guidance for tumour sampling and measurement of disease.”

Meanwhile, the therapeutic space has now firmly entered the immunotherapy era.

“We’ve had some landmark clinical trials and changes in practice that has seen immunotherapy sit alongside chemotherapy as options in the first-line setting and indeed the preferred approach to treat more aggressive forms of mesothelioma,” Associate Professor Linton says.

Surgical practice hays also changed, with clinical trials changing clinicians’ views on the role of radical surgery for mesothelioma.

Associate Professor Linton says the new guidelines capture those major advances and emphasise the importance of multidisciplinary care.

“A multidisciplinary approach remains essential and armed with the latest evidence we will see improved outcomes for patients.”

Cataloguing new treatment approaches 
The recommendations guide clinicians through data on first-line, second-line and third line therapies for advanced mesothelioma, recognising the emerging role of immunotherapies and the importance of clinical trials.

“Randomised controlled trial evidence has been essential in establishing the evidence base to guide our practice, starting with first line chemotherapy with platinum/pemetrexed as the inaugural standard of care from 2003,” the document explains.

“Since then, incremental steps have been made with the addition of bevacizumab until the more recent discovery of ICIs. Superior benefit has been seen with the addition of pembrolizumab to standard chemotherapy, and with combination immunotherapy (nivolumab and ipilumumab) compared with standard chemotherapy.”

Full recommendations for treatment options can be found on page 53 of the guidelines [link here].

Recognising the diagnostic challenge 

Difficulties remain around accurately diagnosing mesothelioma. Australian data suggests 9.5% of cases have a “significant” change in diagnostic category, from either ‘benign’ to ‘malignant’ or vice-versa, or from another tumour type to mesothelioma.

“Whilst in situ mesothelioma is now a recognised diagnostic category, allowing earlier diagnosis, it is not currently recognised as a distinct stage and its prognostic and treatment implications remain under review,” the guidelines state.

But accurate and early diagnosis remains crucial not just for patient outcomes but also for the medicolegal implications. More than 95% of mesothelioma cases are associated with asbestos exposure.

All patients should be informed about the importance of contacting a lawyer experienced in asbestos-related claims as soon as possible after their diagnosis, the recommendations state.

“In Australia, cytology and histology diagnosis is not an absolute requirement for an asbestos-related compensation if there is sufficient clinical and radiological evidence of mesothelioma,” the guideline says.

If the exposure occurs outside of Australia, legal advice should be quickly sought about the requirements for bringing an asbestos-related claim.