Introduction

The 5-year relative survival rate after colorectal cancer (CRC) diagnosis has increased from around 40% in the 1960s to approximately 60% in Sweden.1,–,4 Some probable reasons for the increased survival may be earlier diagnosis, improved treatment and better health status.2 Survival is worse among men1 2 4 and older patients.1 5 In the western countries, around 80% of the patients are diagnosed at ages over 60 years.4 Because the older population frequently suffers from comorbidities, a majority of CRC patients are affected by one or several comorbidities at diagnosis.6 7 Further improvements in the outcome of CRC patients motivate increased knowledge of these comorbidities. The influence of specific comorbidities on CRC mortality has been well covered in previous studies, and results have suggested that several chronic disorders (eg, cardiovascular diseases, diabetes and chronic pulmonary obstructive disease) and the number of comorbidities may affect survival and life expectancy negatively.6,–,12 However, little is known whether CRC patients are at an increased risk to die from specific causes; higher death rates have been described among CRC patients from cardiovascular causes, gastrointestinal causes, injuries13 and suicide.13 14 Furthermore, knowledge of the actual death causes mentioned in death certificates of CRC patients is incomplete. A recent study has shown though, that among deceased CRC patients, 75% had died from CRC itself.15 However, estimates of the actual proportion of cancer patients dying from their primary cancer may vary greatly. For example, in breast cancer, these estimations have varied between 50% and …