To address the emerging concern of oncologists who can expect to see an increasing number of older cancer patients with dementia, this retrospective case–control study compared a sample of older cancer patients with cognitive impairment (N = 86) to a non-cognitively impaired control group (N = 172) as to patterns of care and survival by age, site and stage. Treatment patterns presented much less differences between both groups than in other series. After adjusting for age, sex, performance status, ADLs/IADLs and comorbidity, results showed significantly greater survival (values p < .001) in the non-impaired control group (Mdn = 72.6 months) compared to the cognitively impaired cases (Mdn = 23.0 months). Similar results were found when we compared these groups according to tumor stage and cancer site (breast versus other). Across tumor types and stages, cognitively impaired patients have approximately one-third the median survival of the control group. This survival can still be a significant number of years.