Glioblastoma Survival is Improving Despite Increasing Incidence Rates: A Nationwide Study between 2000 and 2013 in Finland

Abstract

Background: In 2005, a randomized trial reported that chemoradiation including temozolomide improves survival of 18 to 70-year-old glioblastoma patients. Today, that chemoradiation therapy is the standard of care, and used frequently also for elderly patients. We assessed population-level changes in glioblastoma survival between 2000 and 2013 in Finland, with focus on elderly patients (>70 years) in order to assess if changes in treatment of glioblastoma are reflected also in population-based survival rates. Methods: We identified all patients (age ≥18 years) from the Finnish Cancer Registry (FCR) with a histopathological diagnosis of primary glioblastoma in 2000-2013. Patients were followed up until December 2015. The accuracy of register-based search of glioblastoma patients was internally validated. We report age-standardized relative survival ratios and relative excess risks of death (RER) between 2000-2006 (pre) and 2007-2013 (post-period). Findings: We identified 2,045 glioblastoma patients from the FCR. The accuracy of the FCR-based search was 97%. Median age was 63·3 years, and 42% were women. Incidence increased on average by 1·6% and median age by 0·4 years per calendar year. Between the pre and post-period, the proportion of patients >70 years increased from 24% to 27%. In >70-year-old patients, the median survival time increased from 3·6 months in 2000-2006 to 4·5 months in 2007-2013 (RER 0·82, 95% CI 0·68-0·98). In ≤70-year-old-patients, the median survival time increased from 9·3 months in 2000-2006 to 11·7 months in 2007-2013 (RER 0·74, 95% CI 0·67-0·82). Interpretation: Despite the increased proportion of elderly glioblastoma patients, population-level survival of glioblastoma patients have improved since year 2000. However, increasing incidence, increasing age of patients, and poor survival in elderly are alarming, and future studies should perhaps focus more on elderly. Funding: None Conflict of interest: The authors declare no conflict of interest Ethical Approval Statement: The data processing procedures were evaluated and approved by the Helsinki University Hospital’s research committee (HUS/356/2017 §107) and the National Institute for Health and Welfare THL (THL/1009/6.02.00/2018). We conducted the study according to the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines (Electronic Supplementary Material 1).