Survival Analysis and Factors Affecting Treatment Outcome in Glioblastoma Multiforme: A Cohort Study

Abstract

Introduction: High-grade gliomas, especially Glioblastoma Multiforme (GBM), are the most prevalent primary brain tumours in adults. Treating GBM is challenging due to resistant tumour cells, resulting in a dismal prognosis. While GBM often develops spontaneously, familial gliomas have also been identified in 1% of cases. Primary and secondary glioblastoma are the subtypes that affect patients of varying ages and develop via different paths. Aim: To estimate the two year survival and to assess factors affecting survival in patients diagnosed with GBM and to evaluate the “ability for self-care” following treatment. Materials and Methods: The cohort study investigated treatment outcomes in GBM using a sample of 65 patients from the Department of Radiation Oncology at Government Medical College Thrissur, a tertiary care centre in Kerala, India. The patients were diagnosed between January 2018 and December 2019. Survival and the factors determining survival were explored through case records and telephonic interviews with primary caregivers. Median survival and two year survival rates were calculated. The study examined possible associations of survival with patient-related, tumourrelated, and treatment-related factors. Patient-related factors assessed were age, gender, and Eastern Cooperative Oncology Group (ECOG) performance status at diagnosis. Tumour-related factors assessed included tumour location, laterality, and volume based on pretreatment Magnetic Resonance Imaging (MRI). Treatment-related factors such as extent of surgery, postoperative radiotherapy, and chemotherapy were also assessed. Data analysis was performed using the Statistical Package for Social Sciences (SPSS version 21.0). Qualitative variables were expressed in percentage and compared using the Chi-square test or Fisher’sexact test. Quantitative variables were expressed as mean and standard deviation and compared using unpaired t-tests. Telephonic interviews with primary caregivers were conducted to assess the “ability for self-care” following treatment. Results: The study included a total of 65 cases, with a mean patient age of 54 years. Out of the patients, 45 (68%) patients were male, while 20 (32%) patients were female. The median survival for GBM was found to be eight months. The one year and two year survival rates were 18.46% (12 patients) and 10.8% (7 patients), respectively. The survivors had a mean age of 48 years. There were no statistically significant differences in survival based on sex (p-value=0.527), tumour location (p-value=0.765), and laterality (p-value=0.596). Survival was found to be related to ECOG performance status at diagnosis (p-value=0.001) and tumour volume (p-value=0.002). Among the patients, 37 (58%) patients were able to perform self-care after treatment, while 28 (42%) patients were unable to do so. Conclusion: The survival of patients with GBM is related to ECOG performance status at diagnosis and the pretreatment volume of the tumour. The evidence was insufficient to establish a relationship between survival and the administration of postoperative radiotherapy and chemotherapy. Despite multimodality treatment protocols, the survival of patients with GBM remains dismal. A tailored treatment protocol that weighing morbidity of treatment and cost effectiveness on one side and survival on the other side is the need of the hour.

Keywords

• brain tumours
• familial gliomas
• temozolomide