Survival of Patients with Primary Brain Tumors: Comparison of Two Statistical Approaches

Abstract

PurposeWe reviewed the survival time for patients with primary brain tumors undergoing treatment with stereotactic radiation methods at the Masaryk Memorial Cancer Institute Brno. We also identified risk factors and characteristics, and described their influence on survival time.MethodsIn summarizing survival data, there are two functions of principal interest, namely, the survival function and the hazard function. In practice, both of them can depend on some characteristics. We focused on nonparametric methods, propose a method based on kernel smoothing, and compared our estimates with the results of the Cox regression model. The hazard function is conditional to age and gross tumor volume and visualized as a color-coded surface. A multivariate Cox model was also designed.ResultsThere were 88 patients with primary brain cancer, treated with stereotactic radiation. The median survival of our patient cohort was 47.8 months. The estimate of the hazard function has two peaks (about 10 months and about 40 months). The survival time of patients was significantly different for various diagnoses (p≪0.001), KI (p = 0.047) and stereotactic methods (p = 0.033). Patients with a greater GTV had higher risk of death. The suitable threshold for GTV is 20 cm3. Younger patients with a survival time of about 50 months had a higher risk of death. In the multivariate Cox regression model, the selected variables were age, GTV, sex, diagnosis, KI, location, and some of their interactions.ConclusionKernel methods give us the possibility to evaluate continuous risk variables and based on the results offer risk-prone patients a different treatment, and can be useful for verifying assumptions of the Cox model or for finding thresholds of continuous variables.

Comparative Parameters of Occult and Multiple Brain Tumors In Human: The Implication for Therapy

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“…Prognosis of congenital brain tumours is poor with the longest median survival seen in choroid plexus papilloma and astrocytoma, but teratomas are rapidly fatal [43]. However, Kernel statistical method for evaluation of continuous risk variables could be combined with Cox model that determines threshold of continuous variables for determination of survivability of patients with primary brain tumours [29]. Mathematical model of glioblastomas that incorporates tumor growth, cancer cell diffusion and cell proliferation rate is clinically useful and predictive [9].…”

Circulating T cell subsets are associated with clinical outcome of anti-VEGF-based 1st-line treatment of metastatic colorectal cancer patients: a prospective study with focus on primary tumor sidedness

“…The Cox model with interaction term was used to compare effects in subgroups in the Results section part III. Optimal cut points of continuous variables with respect to the survival endpoints were determined using the conditional hazard function which was estimated using smoothing techniques based on kernel methods [35]. Statistical comparison of two Treg quantification approaches was performed using Bland-Altman plot and Passing-Bablok regression in MS Excel.…”

Classification of brain tumour based on texture and deep features of magnetic resonance images

“…Secondary brain tumours are mostly cancerous and patients have a low survival rate (Franchino et al, 2018). Primary tumours are initially non‐cancerous and patients have a high survival rate if detected and classified well in time (Selingerová et al, 2016).…”