Relative Survival of Supratentorial Low-Grade Gliomas

Purpose: The purpose of this study is to assess the population-based estimates of age-standardized survival of patients with low-grade gliomas (LGG) and determine the impact of age and time on relative survival (RS).

Patients and Methods: Data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute from 1973 to 2006 was analyzed to assess survivorship of 5037 patients. Cumulative RS was computed with the SEER expected mortality data and the Ederer II method for expected survival estimation, and modeled using Dickman’s piecewise constant hazards RS model.

Results: The 3- and 10-year age-standardized RS was 67 and 37%, respectively. When analyzed by age group, the 10-year OS and RS for children (<16 years), young adults (16–39 years), adults (40–64 years), and elderly (≥65 years) was 86/86, 61/62, 40/43, and 10/14, respectively. The observed difference in metrics with OS and RS was larger for elderly patients (4%) and smallest for children (<1%). Elderly patients were 30.5 times (estimated hazard ratio [eHR], 95% CI, 20.3–50) as likely to die in the first year as young adults, and 18.2 times as likely to expire during the second year. Adults were 5.3 (eHR, 95% CI, 3.5–8.1) as times likely to die in their first year as young adults. In the remaining years the observe survival differences were substantially decreased, and the presence of an age-by-follow-up interaction was observed.

Conclusions: Survival of elderly patients with LGG is substantially different from the one computed for young adults and children. Despite the hazards across age groups being not proportional RS does, however, not provide additional information, when compared to OS, in patients with LGG.