Characteristics and prognosis of Japanese colorectal cancer patients: The BioBank Japan Project

Background: Colorectal cancer is the third most common cancer worldwide, and in Japan, it is estimated that about 10% of men and 8% of women will be diagnosed with colorectal cancer during their lifetime. Methods: We focused on 5864 participants (3699 men and 2165 women) who had colorectal cancer and were registered with BioBank Japan (BBJ) between April 2003 and March 2008. Characteristics of colon and rectal cancer patients were calculated separately. Among the enrolled patients registered in BBJ within 90 days after diagnosis, we also calculated the 5-year cumulative and relative survival rates, and estimated the effect of lifestyle factors on all-cause mortality. Results: Our participants included younger men than those in the Patient Survey and the Cancer Registry Japan. In more than 95% of cases the histological type was adenocarcinoma both in colon and rectal cancer. Rectal cancer patients tended to eat more meat and less green leafy vegetables compared with colon cancer patients. The 5-year cumulative survival rate was 73.0% (95% CI; 70.1%-75.7%) and the 5- year relative survival rate was 80.6% (77.4%-83.6%), respectively, for colon cancer. For rectal cancer, the rates were 73.3% (69.1%-77.0%) and 80.9% (76.3%-85.0%), in the same order. Lifestyle factors such as consuming less green leafy vegetables, being underweight, smoking, not consuming alcoholic beverages and being physically inactive were found to be related to poor survival. Conclusions: We described lifestyle characteristics of colorectal cancer patients in BBJ and examined the impacts on subsequent all-cause mortality.