Risk factors for unintended discontinuation of tumor-specific treatment after tumor surgery in glioblastoma patients aged 70 or older

Purpose The most beneficial treatment option for newly diagnosed glioblastoma is maximum safe resection and adjuvant therapy. Elderly patients carry a higher perioperative risk for complications, thus, predictors of unfavorable surgical outcome must be evaluated more intensively. Consequently, we sought to evaluate surgery-related paradigms leading to discontinuation of adjuvant treatment after initial neurosurgical resection. Methods Patients receiving microsurgical tumor resection for newly diagnosed glioblastoma CNS WHO grade 4 were evaluated. Further inclusion criteria was age >70 years. Comorbidities were summarized using the Charlson Comorbidity Index (CCI), the 5 and 11 item modified frailty index (mFI-5 and mFI-11) and the CHA(2)DS(2)-VASc Score. Primary endpoint was discontinuation of tumor-specific before completion of adjuvant radiotherapy or radio-chemotherapy. Results 102 patients were included, mean age was 76.2 +/- 4.2 years. The median extent of contrast-enhancing tumor volume was 99.1 +/- 5.9 %. Surgical morbidity and mortality prohibited beginning of adjuvant treatment in 19 patients (18.6 %) and overall discontinuation of treatment before completion of radiotherapy was observed in 26/87 patients (29.9 %). Treatment failure was associated with increasing patient age (p = 0.04) and greater comorbidity scores. The mFI-5 and mFI-11 outperformed the CCI and the CHA(2)DS(2)-VASc Score. Two or more points in the 5- and 11-item mFI were significantly associated with increased risk of treatment failure (p = 0.004 and p = 0.001, respectively). Conclusion In Glioblastoma patients, advanced age and comorbidities are relevant confounders and put patients at risk for surgery-related morbidity. Nevertheless, it can be aimed at a maximum safe resection with acceptable surgical morbidity.