MORTALITY IN YOUNG FIRST-DEGREE RELATIVES OF PATIENTS WITH FAMILIAL ADENOMATOUS POLYPOSIS

Background. Mortality and cancer deaths among young family members of patients with familial adenomatous polyposis (FAP) were investigated. Methods. The subjects were 1764 members of 628 families with FAP registered at the authors' Polyposis Registry, They consisted of first-degree relatives of patients with FAP, excluding the propositus. These 1764 subjects were born between 1960 and 1978. Their survival times and causes of death were certified mainly by the National Family Registry and death certificates. Relative mortality rates were calculated based on the calendar year, age, sex, and cause-specific death rate of Japanese people in the Vital Statistics, (Ministries of Health and Welfare, Japan, Vital statistics, Japan, Vol. 1960-1990. Tokyo: Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare.) 1960-1990,Japan. Results. There were 69 deaths before the age of 25 years. Deaths from malignant tumor were observed in 20 cases. Overall relative mortality rate in the subject group younger than age 20 years was 1.48. Relative cancer mortality in the age group between 1 and 4 years was significantly higher, because the relative mortality from hepatoblastoma in this age group was 176. Relative cancer mortality rate was significantly higher among males 15-19 years of age (15.4) and 20-24 years of age (male, 33.3; female, 150) due to colorectal cancer. Conclusions. Hepatoblastoma was a specific cancer in the 1- to 4-year-old age group in first-degree family members of patients with FAP. The incidence of colorectal cancer considerably increased, starting around the age of 20 years.