Is it reasonable to deny older patients treatment for glioblastoma?

Is it ever fair to limit treatment for diseases like glioblastoma for which prognosis is poor? Because resources are finite and health care spending limits the other possible uses for those resources, limiting access to an intervention that does not generate benefits is ethically sound. Ignoring the balance of benefits and burdens associated with treatment ignores opportunity costs and leads us to treat some lives as more valuable than others. Although it is ethically sound to set limits on medical care, I argue that biological age is a poor criterion for allocating resources.