Gender differences in colorectal cancer incidence, mortality, hospitalizations and surgical procedures in Canada.

BACKGROUND: Over the past few decades there have been changes in incidence and mortality of colorectal cancer.
OBJECTIVE: To examine gender differences in incidence, hospitalization, hospital-based procedures and mortality for colorectal cancer.
METHODS: Data were derived from the Hospital Morbidity Database, Canadian Cancer Registry and the Canadian Mortality Database.
RESULTS: Overall incidence and mortality rates for colorectal cancer are decreasing, but remain substantially higher for males. Absolute numbers of cases are similar for men and women. The top subsite for men was rectal cancer, which was third highest for women, whereas right colon cancer was highest for women. Male/female ratios for incidence and surgeries were highest for distal cancer and are increasing with time.
CONCLUSIONS: Although overall incidence rates have shown a decline, absolute numbers of new colorectal cancer cases have increased. While men have higher colorectal cancer rates, women have similar numbers and screening should target both equally. Over the years, colorectal cancer subsites are showing a rightward shift, i.e. an increase in proximal subsites, but a leftward shift in male/female ratios, i.e. a greater decrease for the more distal subsites in females. The lower rates for women for distal cancer are compatible with a degree of hormonal protection based on oral contraceptive and hormone replacement therapy. Colorectal cancer will continue to be a considerable public health problem in the foreseeable future.