Colorectal cancer is the most frequently diagnosed cancer in Spain. Cancer treatment and outcomes can be influenced by tumor characteristics, patient general health status and comorbidities. Numerous studies have analyzed the influence of comorbidity on cancer outcomes, but limited information is available regarding the frequency and distribution of comorbidities in colorectal cancer patients, particularly elderly ones, in the Spanish population. We developed a population-based study of all incident colorectal cancer cases diagnosed in Spain in 2011 to describe the frequency and distribution of comorbidities, as well as tumor and healthcare factors. Data were obtained from two population-based cancer registries and the complete revision of patients’ digitalized clinical records history. We then characterized the most prevalent comorbidities by patient, tumor and health care factors, as well as dementia and multimorbidity, and developed an interactive web application to visualize our findings. The most common comorbidities were diabetes (23.6%), chronic obstructive pulmonary disease (17.2%), and congestive heart failure (14.5%). Dementia was the most common comorbidity among patients aged ≥75 years. Patients with dementia had a 30% higher prevalence of being diagnosed at stage IV and the highest prevalence of emergency hospital admission after colorectal cancer diagnosis (33%). Colorectal cancer patients with dementia were nearly three times more likely to do not receive surgical treatment. Age ≥75 years, obesity, male sex, being a current smoker, having surgery more than 60 days after cancer diagnosis, and not receiving surgical treatment were associated with a higher prevalence of multimorbidity. Patients with multimorbidity aged ≥75 years showed a higher prevalence of hospital emergency admission followed by surgery the same day of the admission (37%). We found a consistent pattern in the distribution and frequency of comorbidities and multimorbidity among colorectal cancer patients. The high frequency of stage IV diagnosis among patients with dementia and the high proportion of older patients not receiving surgical treatment are significant findings that require policy actions.

The pattern of Comorbidities and Multimorbidity among Colorectal Cancer Patients in Spain: CoMCoR study