(HealthDay News) — Although the overall mortality rate of glioblastoma is high, compared with patients newly diagnosed with glioblastoma, those who survive two years or more after diagnosis have a favorable conditional probability of future survival, according to a study published online May 8 in Cancer.
To investigate the conditional probability of survival, Derek R. Johnson, M.D., of the Mayo Clinic in Rochester, Minn., and colleagues conducted a population-based analysis using Surveillance, Epidemiology, and End Results data from 10,022 patients diagnosed with glioblastoma between 1998 and 2008 who had been treated with radiation-containing regimens.
The researchers found that median survival for the cohort was 12.61 months. At diagnosis, the conditional probability of surviving an additional two years was 19.8 percent and this increased to 65.9 percent at five years after diagnosis. Compared with patients diagnosed in 1998 to 2004, an increased proportion of patients diagnosed in 2005 to 2008 survived 12 months from diagnosis and from six, 12, and 18 months after diagnosis. Age was the only factor associated with a higher risk of death at diagnosis and at one and three years following diagnosis.
“Patients surviving past two years from diagnosis have a relatively favorable conditional probability of survival into the future compared to newly diagnosed patients,” the authors write. “This effect becomes more pronounced with increasing time since diagnosis. These data will assist in the counseling of glioblastoma survivors.”