Clinical Aspect of Suspected HNPCC in Korea

ABSTRACT

PURPOSE: The criteria for Suspected hereditary nonpolyposis colorectal cancer(Suspected HNPCC) has been devised by the Korean Hereditary Tumor Registry for families who do not fulfill Amsterdam criteria, but hereditary background is strongly suggested. This study was performed to define the clinical characteristics of 'Suspected HNPCC'. METHODS: The 'Suspected HNPCC' criteria include the followings a) vertical transmission of colorectal cancer or at least two siblings affected with colorectal cancer in a family and b) development of multiple colorectal tumors (including adenoma) or at least one colorectal cancer case diagnosed before the age of 50 years or development of extracolonic cancers (endometrium, urinary tract, small intestine, stomach, hepatobiliary system, ovary) in family members. We analysed the clinical characteristics of 93 patients from 39 Suspected HNPCC families and compared these characteristics with 176 HNPCC familes and with 1,204 non-hereditary colorectal cancer patients. RESULTS: The mean age of Suspected HNPCC patients at the time of diagnosis (49.0 years) was significantly lower than that of non-hereditary colorectal cancer patients (56.1 years), but higher than that of the HNPCC patients (44.5 years). Tumors were more frequently located in the right colon (34%) in Suspected HNPCC compared to non-hereditary colorectal cancer (23%). Dukes' A and B cancers were more frequent in the Suspected HNPCC as compared to non-hereditary colorectal cancer (55% vs. 48%, p<0.05), but tumor differentiation was not statistically different between the two groups. Among the Suspected HNPCC, 24.0% of the patients had synchronous adenomatous polyps and 20.0% had synchronous colorectal cancers and 15.6% had metachronous polyps or cancers. These findings were similar to HNPCC, but significantly higher than non-hereditary colorectal cancers (p<0.05). In Suspected HNPCC families, 42 patients had extracolonic malignancies with the stomach cancer being the most common (n=22). CONCLUSION: These data indicate that the clinical characteristics of Suspected HNPCC are similar to those of HNPCC and may suggest that the management principles of the HNPCC should also be applied to the Suspected HNPCC.