Glioblastoma in Patients over 70 Years of Age

Glioblastoma has in last 20 years seen the steady increase of incidence, which is most prominent in the group of older patients. These older than 70 years have significantly poorer prognosis than other patients and are considered a distinct group of glioblastoma patients. Modified prognostic factors are being used in these patients and this information is lately supplemented with the genetic and epigenetic information on tumour. The therapy is now often tailored accordingly. The aim of our study was to analyse the current treatment of the glioblastoma patients over 70 years of age to determine the impact of clinical prognostic factors.

Among patients treated at the Institute of Oncology Ljubljana between 1997 and 2015, we found that 207 were older than 70 years. We analysed their survival, clinical prognostic factors (age, performance status) treatment modalities (extent of surgery, radiation dose, chemotherapy).

Median survival of patients older than 70 years was 5.3 months which was statistically significant inferior to the survival of younger patients (p < 0.001). The clinical prognostic factors that influenced survival the most were performance status (p < 0.001), extent of surgical resection (p < 0.001), addition of temozolomide (p < 0.001) and addition of radiotherapy (p = 0.006). Patients receiving concomitant radiochemotherapy with temozolomide followed by adjuvant temozolomide, had same median survival as patients receiving adjuvant temozolomide after completion of radiotherapy.

The increase of the number of older patients with glioblastoma corresponds to the increase in the life expectancy but in Slovenia also to the increased availability of diagnostic procedures. Clinical prognostic markers are helpful in decision on the aggressiveness of treatment. Radiotherapy and temozolomide have the biggest impact on survival, but the radiotherapy dose seems to be of secondary importance. In selected patients, chemotherapy alone might be sufficient to achieve an optimal effect. Patients that were fitter, had more aggressive surgery, and received temozolomide fared the best. The scheduling of the temozolomide seems to have limited impact on survival as in our study, there was no difference weather patients received temozolomide concomitant with radiotherapy or after the radiotherapy. Thus far, our findings corroborate the usefulness of recursive partitioning analysis (RPA) classes in clinical decisions.