Short and long term post-operative outcomes in elderly versus very elderly glioblastoma patients

Glioblastoma is the most common and lethal adult primary brain cancer, and its incidence is predicted to increase among older patients. Elderly age has been associated with worse outcomes compared to younger patients with glioblastoma. It is unknown if very elderly patients are at even further increased risk of worse outcomes compared to elderly patients.

Patients ≥ 65 years old with primary glioblastoma treated surgically at a single institution (6/1/2008-12/31/2020) were identified through chart review. Patient demographics, disease characteristics, management data, and clinical outcomes were collected. Kaplan-Meier curves were generated to study overall survival. Chi square, independent t, and Wilcoxon-Mann-Whitney tests were used to identify associations between variables, and factors that affected clinical outcomes were identified using a multivariate logarithmic regression model. P-values < 0.05 were considered significant.

A total of 165 elderly (65-74 years) and 79 very elderly (≥ 75 years) patients were included. Compared to elderly patients, very elderly patients were more likely to have a higher mFI-5 score (elderly 0.8 ± 0.9; very elderly 1.2 ± 0.9; p = 0.0018) and lower KPS score (elderly 73.6 ± 16.3; very elderly 69.1 ± 16.3; p = 0.0439) pre-operatively. Very elderly patients were less likely to receive post-operative adjuvant radiotherapy (elderly 70.4 %; very elderly 56.6 %; p = 0.0359) or adjuvant temozolomide chemotherapy (elderly 37.2 %; very elderly 21.3 %; p = 0.0165). In multivariate analysis, age ≥ 75 years was an independent predictor of extended ICU (OR 4.71, p = 0.0045) and overall length of stay (OR 2.03, p = 0.0374) compared to elderly patients. Adjuvant chemoradiation was associated with increased median overall survival in both the elderly (p < 0.0001) and very elderly (p < 0.0001).

Very elderly patients with glioblastoma may be less likely to receive adjuvant chemoradiation than elderly counterparts, but use of these modalities is associated with increased overall survival in both cohorts.