FAMILY HISTORY IN PARTICIPANTS OF BREAST-CANCER SCREENING

Of 12,337 participants of mass screening for breast cancer (screenees) in Gunma Prefecture between 1980 to 1985, 1,000 participants' records in Gunma Prefecture were investigated. The records of screenees who h ad already developed breast cancer were excluded. The rate of screenee s who had a family history (FH) of cancer in first- and second-degree relatives was compared with that of 1,248 breast cancer patients (cont rols) using the conditional logistic regression model. The mean age of screenees (49 y.o.) was similar to that of controls (51 y.o.). The nu mber of screenees with positive FH of cancer including other malignanc ies was 530 with the odds ratio of 2.68. This was statistically signif icant with chi-square test. The rates of screenees with positive FH of cancer were quite similar in the seven districts. Screenees had a sig nificantly larger number of relatives with a positive FH of breast can cer compared with the controls. The rate of positive breast cancer his tory in parents of screenees was significantly higher than in the pare nts of controls. Rates of positive breast cancer history in grandmothe rs and aunts of screenees were also significantly higher than that in the controls. The rate of breast cancer history in sisters was not dif ferent between the two groups. Screenees had a higher rate of positive FH of cancer in parents, especially in mothers. Family histories of s tomach, liver, lung, and uterus cancer in parents were more frequently observed in screenees compared with the controls and those cancer his tories were also frequently observed in other family members of screen ees. These data showed that a FH of cancer is one of the primary motiv ations of participation in the breast cancer screening program. Partic ipants seemed to be intrinsically a high risk group of breast cancer.