Glioblastoma multiforme risk analysis
Curren WJ, et al. Recursive partitioning analysis of prognostic factors in three radiation therapy oncology group malignant glioma trials. J. Nat. Cancer Inst. 85:704-710,1993

Subgroups of patients with malignant gliomas (anaplastic astrocytoma and glioblastoma) benefit from maximal tumor removal, external beam radiation therapy and nitrosourea chemotherapy. These benefits were established by studies in the 1970's but since that time there have been few advances in the treatment of malignant gliomas (GBM and anaplastic astrocytoma) in terms of survival benefit. Outcome trials are influenced by pretreatment variables such as age, tumor type, neurological condition, etc and it is important to identify their significance in order to design valid outcome studies.

This was a retrospective study of 1578 patients enrolled in three previous Radiation Therapy Oncology Group (RTOG) studies from 1974 to 1989. The survival results were updated to 1991. A sophisticated statistical analysis of length of survival, based of multiple risk factors was performed by Curren and associates which ranked the risk factors by levels of significance:

                    Survival risk factors malignant gliomas

Median survival
 

(months)
   
Total 1578 patients:  11.3 
   
Age under 50 years: 18.8
    anaplastic astrocytoma 49.4
         normal mental status 58.6
         abnormal mental status 18.4
   glioblastoma 13.7
         no symptoms  (KPS > 90) 17.6
         any symptoms   (KPS < 90) 10.7
 
Age over 50 years:  8.8
   living independently  (KPS >70) 10.3
         anaplastic astrocytoma 21.7
               symptoms more than 3 months 37.5
               symptoms less than 3 months 11.7
         glioblastoma  9.7
               partial/total surgical removal 10.3
                    able to work 11.4
                    not able to work  9.2
               biopsy only  6.2
                    radiotherapy dose > 54.4 Gy  8.3
                    radiotherapy dose < 54.4 Gy  4.3
   not living independently   (KPS < 70)   5.3
               normal mental status  8.1
               abnormal mental status  4.7

Obviously risk factors greatly influence survival from malignant gliomas as median survival rates varied from 4.3 months to 58.6 months, depending upon the accumulation of risks. For future treatment studies to show slightly significant advances in survival, careful control of these risk factor is necessary for the treated and untreated (control) groups of patients. It is also obvious that much work needs to be done in improve the outlook for these individuals.