Clinicopathological Characteristics of Multiple Primary Colorectal Cancer

ABSTRACT

PURPOSE: Through studying the clinical manifestation and prognosis of multiple colorectal cancer in comparison to those of solitary primary colorectal cancer, we expect this study to help establish a strategy for the diagnosis and treatment of it. METHODS: 2,302 patients with colorectal cancer, operated at the department of surgery, Yonsei university college of medicine, between Jan. 1989 and Dec. 1999 were evaluated for multiple colorectal cancer. Synchronous cancer was defined as distinct lesions separated by a distance of greater than 4 cm with the invasion of the tumor below the muscularis mucosa at the time of diagnosis. Metachronous cancer was defined as the development of colon cancer more than 6 months after the initial treatment without evidence of recurrence or metastasis from the primary tumor. RESULTS: The incidence of multiple cancer was 2.1% (49 patients). Among them, 1.8% were synchronous and 0.3% were metachronous. The average age was 59.7 years old, similar to the solitary colorectal cancer group whose mean age was 57.1 years old. The median follow up period was 44 months and average follow up period was 53 months. The frequency of cancer increased as it got closer to the rectum. The most frequent location was the rectum (43%) and the sigmoid colon (24%). The average time interval until the development of metachronous cancer was 46 months after initial operation. Adenomatous polyps were identified in 11 patients (43%) out of 49 patients with multiple colorectal cancer, whereas 538 patients (24%) out of 2,253 patients with solitary colorectal cancer were discovered with ademomatous polyps. The survival rate of multiple colorectal cancer was 59%, lower than that of solitary colorectal cancer (64%). But the difference was not statistically significant (P>0.05). CONCLUSIONS: The diagnosis of multiple colorectal cancer is very important in view of curative radical surgery and prognosis. This emphasizes the need for detection of early stage cancer by developing genetic markers and using advanced radiological diagnostic tools.