Pathologic characteristics of colorectal cancer in the elderly

To determine the pathologic characteristics of colorectal cancer in the ver y old, a retrospective study of 947 consecutive Japanese patients aged grea ter than or equal to 65 with 1,039 lesions were examined. Pathologic findin gs in the very old group (>85 years, n = 140) were compared with those in t he younger groups; young-old group (65-74 years, n = 352) and middle-old gr oup (75-84 years, n = 455). Although male:female ratio significantly decrea sed with advancing age, reaching 1:1.8 in the very old group, the relative odds of colorectal cancer in men were higher than that in women in all age groups. In the very old group, cancer of the proximal colon (proximal to th e splenic flexure) accounted for 52% in women and 37% in men, being signifi cantly higher than those in the younger groups. Proximal colonic cancers in creased with advancing age in both genders. Higher proportions of poorly di fferentiated adenocarcinoma, mucinous carcinoma, cancer >5 cm in size, and protruding type cancer were present in the very old group, although these k inds of tumors typically occur in the proximal colon. The incidence of mult iple cancers in the large intestine was not different among any age group ( average, 8.6%). These results indicated that, even in the very old, colorec tal cancers showed marked proximal excess, being explained by effect of bot h age and gender, and that the proximal shift may influence the proportion of histologic type and size of the tumor. These findings have important imp lications for screening and diagnosis of colorectal cancer in the elderly.