At the Princess Margaret Cancer Centre in Toronto, Canada, medical professionals have suggested that the ‘promising’ combination of immunotherapy and hypofractionated radiation could become the standard of care for pleural mesothelioma patients.[i]
Hypofractionated radiation is a specific type of radiation treatment, whereby:
‘... the total dose of radiation is divided into large doses and treatments are given once a day or less often. Hypofractionated radiation therapy is given over a shorter period of time (fewer days or weeks) than standard radiation therapy’.[ii]
In 2015, the same group of Toronto researchers used a Surgery for Mesothelioma After Radiation Therapy (SMART) approach, which is the reverse of the traditional approach (aggressive surgery followed by radiation). The SMART initiative yielded a 3-year survival rate of 66% among mesothelioma patients, with estimated disease-free survival of 47 months and median overall survival of 51 months.[iii]
In an editorial, recently published in the Journal of Thoracic Disease, Dr Mark de Perrot, thoracic surgeon and mesothelioma specialist at Toronto General Hospital, stated that the 2015 study was proof that ‘non-ablative, hypofractionated radiation can also have a major impact on the immune system in mesothelioma’. He went on to say:
Hence, the combination of non-ablative hypofractionated radiation with targeted immunotherapy is a promising strategy for the near future in mesothelioma’.
This is a reference to a new initiative, called Surgery for Mesothelioma After Radiation Therapy using Extensive pleural Resection (SMARTER). When launched, this will integrate a second phase of immunotherapy. Dr John Cho, at the Cancer Centre’s Clinical Research Unit, anticipates that:
‘Immunotherapy is here to stay, but the question is how to integrate it with therapies we already have’.
The inclusion of immunotherapy will require less toxic pre-surgical hypofractionated radiation levels than those administered in the SMART trial:
‘If the dosage is too low, it doesn’t do much in terms of killing the cancer cells, but too much radiation can be immunosuppressive’.
We will report on the results of the enhanced SMARTER trial in due course.
[i] Tim Povtak, ‘Radiation Could Make Mesothelioma Immunotherapy More Effective’ (2 November 2018 Asbestos.com) <https://www.asbestos.com/news/2018/11/02/radiation-mesothelioma-immunotherapy-effective/> accessed 12 November 2018.
[ii] ‘NCI Dictionary of Cancer Terms’ (National Cancer Institute) <https://www.cancer.gov/publications/dictionaries/cancer-terms/def/hypofractionated-radiation-therapy> accessed 12 November 2018.
[iii] Tim Povtak, ‘SMART Approach Is Advancing Mesothelioma Survival Rates’ (14 December 2015 Asbestos.com) <https://www.asbestos.com/news/2015/12/14/smart-approach-mesothelioma-survival-rates/> accessed 12 November 2018.