Causes of Cancer Death Among First-Degree Relatives in Japanese Families with Lynch Syndrome.

AIM: To elucidate the causes of cancer death in Japanese families with Lynch syndrome (LS).

METHODS: The distributions of cancer deaths in 485 individuals from 67 families with LS (35, 30, and two families with MutL homologue 1 (MLH1), MSH2, and MSH6 gene mutations, respectively), obtained from the Registry of the Japanese Society for Cancer of the Colon and Rectum were analyzed.

RESULTS: Among 98 cancer deaths of first-degree relatives of unknown mutation status, 53%, 19%, 13% (among females), 7% (among females) and 5% were due to colorectal, gastric, uterine, ovarian, and hepatobiliary cancer, respectively. The proportion of deaths from extra-colonic cancer was significantly higher in families with MSH2 mutation than in those with MLH1 mutation (p=0.003).

CONCLUSION: In addition to colonic and uterine cancer, management and surveillance targeting gastric, ovarian and hepatobiliary cancer are considered important for Japanese families with LS. Extra-colonic cancer in families with MSH2 mutation might require for more intensive surveillance.