Abstract
BACKGROUND: Colorectal cancer (CRC) treatment and patient survival improved greatly. Consequently an increased incidence of non-cancer-related deaths is observed. This study analyzed the causes of non-cancer death for people suffering from CRC based on the year of diagnosis, follow-up time, and patient's age. METHODS: The data from patients diagnosed with CRC in the years 2000-2016 were taken from the Surveillance, Epidemiology, and End Results 18 database. Patients were categorized according to: death from CRC, non-CRC cancer, and non-cancer. Constituent ratios and standardized mortality ratios (SMRs) were calculated to describe the death causes distribution and relative death risks. RESULTS: Between 2000 and 2016, a stable and rapid drop for the original diagnosis as death cause for CRC patients was observed (70.19% to 49.35%). This was coupled to an increase in non-cancer-associated death reasons (23.38% to 40.00%). The most common non-cancer death cause was heart disease, especially for elderly patients. However, deaths from accidents and adverse effects were frequent in younger CRC patients. Patients died from septicemia more often within the first follow-up year; however, a 6-fold increase in death from Alzheimer's disease was found for after at least 180 months follow-up time. The SMRs of all 25 non-cancer death causes initially decreased in all CRC subgroups, followed by an increase with follow-up times. Gradually decreasing SMR values were observed with increasing age of CRC patients. CONCLUSIONS: These findings could help modify and sharpen preventive measures and clinical management and raise physician's awareness to potential non-CRC death risk factors for CRC patients.