Abstract
From January 1969 through April 1989, 384 patients with colorectal cancer were operated on in our department. In 21 cases (group A) the cancers were associated with multiple primary malignant tumors and clinical studies were carried out on these cases and compared with the 363 cases (group B) without other malignant tumors. Group A had the following features. The male/female ratio was 3.2 to 1; the mean age was 61.7 years, about 4 years older than that of group B; and the rate of multiple colorectal cancers was 28.6%. The cancers tended to be located in the right side colon (the cecum, ascending colon and transverse colon) in contrast to group B. A family history of cancer was noted in 55.6% of the members of group A. The other primary malignant tumors frequently originated in the stomach or urinary bladder. After treating the other malignant tumors, early detection of colorectal cancer must be attempted to improve the prognosis of multiple primary malignant tumors associated with colorectal cancer. Special attention must be paid not to overlook new malignant tumors of other organs, especialy in cases of multiple colorectal cancers, old age, cancer family history, or carcinoma of the right side colon.
