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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Associate Professor Annika Malmström, Linköping University, Sweden
- Second opponent: Clinical Associate Professor Slavka Lukacova, Aarhus University, Denmark
- Third member and chair of the evaluation committee: Professor Lasse Pihlstrøm, University of Oslo
Chair of the Defence
Professor Emeritus Erik Taubøll, University of Oslo
Principal Supervisor
Professor Petter Brandal, Oslo University Hospital
Summary
Glioblastoma (GB) is an aggressive primary brain tumor. The objectives were to study treatment strategies for tumor recurrence at Oslo (OUH) and Haukeland (HUH) university hospitals, the incidence and predictive factors of pseudoprogression (PsP) after radiotherapy (RT), and the impact of the implementation of the cancer patient pathway (CPP) for patients with high-grade gliomas on time from surgery to RT as well as on survival. All studies had a retrospective cohort design and included adult patients with histologically confirmed GB.
Treatment strategies for tumor recurrence varied slightly between the hospitals. HUH used bevacizumab-containing chemotherapy and focused RT, such as gamma knife, more frequently, while OUH more often gave chemotherapy alone. Although treatment approaches varied somewhat, overall survival did not differ significantly.
Pseudoprogression, a form of treatment-related effect after RT, is often difficult to distinguish from true neoplastic progression. In our material, PsP occurred in 19% of cases at three months and in 7% at six months after RT. Methylated MGMT (O6-methylguanine-DNA methyltransferase) promoter and stable neurology were predictive of PsP. In addition, patients with PsP had longer survival than those with true progression.
The implementation of the CPP for patients with high-grade glioma in 2015 had two major effects: it significantly increased the proportion of patients starting RT within four weeks after surgery, and it was associated with improved survival. However, the exact timing of RT after surgery did not have an independent impact on overall survival.
In conclusion, while treatment practices for recurrent GB vary somewhat between hospitals, overall survival remains comparable. Pseudoprogression is common after RT and is associated with specific predictive factors. Finally, the implementation of the CPP for patients with high-grade gliomas had a positive impact on survival, although RT timing alone was not decisive.
Additional information
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