Gender differences in colorectal cancer during the past 20 years in Taiwan.

Purpose: Gender differences in colorectal cancer (CRC) incidence have been previously reported. We designed this population-based study to determine if this gender difference was restricted to specific patient subgroups. Methods: Using the Taiwan Cancer Registry database, we identified a total of 124,314 CRCs registered from 1988 to 2007. We compared the incidence of CRCs by gender in all CRCs, in colon and rectal cancers considered separately, and in right-sided versus left-sided colon cancers. Results: In individuals aged 50 years and older, the incidence of CRCs was lower in females compared with males. For right-sided colon cancers, the incidence in both genders was similar. Because the proportion of right-sided colon cancer accounted for only one fourth of the total CRCs, its influence on the incidence of total CRCs is reduced. Conclusions: Although the incidence of total CRCs is male dominant, the actual gender difference in CRC incidence in Taiwan is limited to the left side of the colon. [ABSTRACT FROM AUTHOR]