Severity of dementia and survival in patients diagnosed with colorectal cancer: a national cohort study in England and Wales

Abstract

Aims: There is little evidence about the survival of patients with colorectal cancer (CRC) also diagnosed with dementia. We quantified dementia severity and estimated how it is associated with 2-year overall survival. Materials and methods: Records of patients aged 65 years or older diagnosed with CRC in England and Wales were identified. A novel proxy for dementia severity combined dementia diagnosis in administrative hospital data with Eastern Cooperative Oncology Group performance status. Cox regression was used to estimate hazard ratios with and without risk adjustment. Results: In total, 4033 of 105 250 CRC patients (3.8%) had dementia recorded. Two-year survival decreased with increasing dementia severity from 65.4% without dementia, 53.5% with mild dementia, 33.0% with moderate dementia to 16.5% with severe dementia (hazard ratio comparing severe with no dementia: 2.97; 95% confidence interval 2.79, 3.16). Risk adjustment for comorbidity and cancer stage reduced this association slightly (hazard ratio 2.52; 95% confidence interval 2.37, 2.68) and additional adjustment for treatment factors reduced it further (hazard ratio 1.60; 95% confidence interval 1.50, 1.70). Conclusions: Survival of CRC patients varied strongly according to dementia severity, suggesting that a 'one-size-fits-all' policy for the care of CRC patients with dementia is not appropriate. Comprehensive assessment of cancer patients with dementia that considers dementia severity is essential in a shared decision-making process that ensures patients receive the most appropriate treatment for their individual needs and preferences.