Treatment approach and survival from glioblastoma: results from a population-based retrospective cohort study from Western Norway

Abstract

Objectives: To evaluate treatment and survival from glioblastoma in a real-world setting.

Design and settings: A population-based retrospective cohort study from Western Norway.

Participants: 363 patients aged 18 years or older diagnosed with glioblastoma between 1 January 2007 and 31 December 2014.

Primary and secondary outcome measures: Overall survival and survival rates determined by Kaplan-Meier method, groups compared by log-rank test. Associations between clinical characteristics and treatment approach assessed by logistic regression. Associations between treatment approach and outcome analysed by Cox regression.

Results: Median overall survival was 10.2 months (95% CI 9.1 to 11.3). Resection was performed in 221 patients (60.9%), and was inversely associated with age over 70 years, higher comorbidity burden, deep-seated tumour localisation and multifocality. Median survival was 13.7 months (95% CI 12.1 to 15.4) in patients undergoing tumour resection, 8.3 months (95% CI 6.6 to 9.9) in patients undergoing biopsy and 4.5 months (95% CI 4.0 to 5.1) in patients where no surgical intervention was performed. Chemoradiotherapy according to the Stupp protocol was given to 157 patients (43%). Age over 70 years, higher comorbidity burden and cognitive impairment were associated with less intensive chemoradiotherapy. Median survival was 16.3 months (95% CI 14.1 to 18.5), 7.9 months (95% CI 6.7 to 9.0) and 2.0 months (95% CI 0.9 to 3.2) in patients treated according to the Stupp protocol, with less intensive chemoradiotherapy and with best supportive care, respectively. Surgical resection (HR 0.61 (95% CI 0.47 to 0.79)) and chemoradiotherapy according to the Stupp protocol (HR 0.09 (95% CI 0.06 to 0.15)) were strongly associated with favourable overall survival, when adjusted for clinical variables.

Conclusions: In a real-world setting, less than half of the patients received full-course chemoradiotherapy, with a median survival comparable to results from clinical trials. Survival was considerably worse in patients receiving less intensive treatment. Our results point out a substantial risk of undertreating glioblastoma, especially in elderly patients.

Keywords: adult oncology; chemotherapy; neurological oncology; radiation oncology.

Figure 1

Overall survival in 363 adults diagnosed with glioblastoma between January 2007 and December 2014. (A) Survival by age. (B) Survival by surgical treatment. (C) Survival by chemoradiotherapy. (D) Survival by chemoradiotherapy in patients aged 70 years or older. Stupp protocol is here defined as completed radiation therapy in total dose of 60 Gy in 2 Gy fractions, concomitant temozolomide in the entire radiation therapy period and completed at least one out of six planned temozolomide monotherapy courses. Cumulative survival in months with 95% CI bands. Groups compared with log-rank test.

Figure 2

Alluvial diagram visualising associations between combination of treatment modalities and median survival in an unselected cohort of 363 patients diagnosed with glioblastoma between January 2007 and December 2014. The width of the curves represents the absolute number of patients. The colours of the curves correspond to median survival in months. TMZ, temozolomide.