Features of colorectal cancer in China stratified by anatomic sites: A hospital-based study conducted in university-affiliated hospitals from 2014 to 2018

The clinical and biological characteristics of colorectal cancer have been found to differ depending on the anatomic site of the cancer. However, for Chinese patients, there is limited information on the proportion of cases at each site and the related features. In this study, we explored the location, distribution and other features of colorectal cancers at each anatomic site in Chinese patients.We conducted a hospital-based study using hospitalization summary reports from 10 Peking University-affiliated hospitals from 2014 to 2018; the reports covered a total of 2,097,347 hospitalizations. Incident cases were chosen as the study population, and their epidemiological features were further analyzed.A total of 20,739 colorectal cancer patients were identified. Rectum was the most common location (48.3%) of the cancer, whereas the proportions of patients with distal and proximal colon cancer were 24.5% and 18.6%, respectively. Patients with rectal cancer were predominantly male and were the youngest for all anatomical sites (each P<0.001). The highest proportion of emergency admissions, the longest hospital stays and the highest hospitalization costs were found in patients with proximal colon cancer (each P<0.001). The proximal colon cancer subgroup included the highest proportions of patients with medical histories of cholecystectomy, cholecystolithiasis and/or gallbladder polyps and appendectomy (P=0.009, P<0.001 and P<0.001, respectively). The distal colon cancer subgroup included the highest proportions of patients with medical histories of diabetes and hypertension (P<0.001, respectively).The patterns of colorectal cancer observed in this study differ from those reported for Western patients and show a significantly higher proportion of patients with rectal cancer. Different epidemiological features were also found based on anatomic sites. Further studies based on tumor location should be conducted to facilitate more accurate screening and treatment.