INCREASED BREAST CANCER RISK IN YOUNG WOMEN AFTER LONG TERM DC USE

Also with first-trimester abortion before full term pregnancy Previous case-control studies showing little evidence of an increased risk of breast cancer in oral oomraoeptive (00 users have measured the risk associated with OC use in the middle and later years of reproductive life. Now a case-control study of 163 breast cancer patients aged less than 33 years at lhe time of diagnosis has shown clearly that ' lo ng -te rm us e of oral contraceptives before the first full · term pregnancy may carry a substa"t~lIy increased risk of breast cance,'. The relative risk (RR) for OC use before flf~t full term pregnancy (FFfP) was roughly doubled. but showed a high significant trend of increasing risk with increasing length of use- RR = 2.2 at 6 years, 3.5 for 8 or more years' use. The increased risk oould not be explained by other risk factors. ex:: use after FfTl> did not show a statistically significant relationship with the risk of breast cancer. The relative risk of breast cancer with OC use was greater in women who had had benign breast disease. The data also suggested that the risk associated with early OC use may be greater in women with a ramily history of breast cancer or with early menarche. Another disturbing fi nding was that first-trimester abortion (spontaneous or inducr.d) before FFTP also clearly increases the RR of breast cancer-to 2.4. This risk was reduced to 1.8 in women who subsequently had a FFfP. Abortion later than 3 months into presnancy and after the FFfP did not carry an increased risk of breast cancer. It is suggested thai in early first presn.ancy, breast tissue may be merely proliferating. Then fu ll term pregnancy brings about a protective effect by a combination of eel! differentia,tion and possibly permanently changed hormone leve1s. Pike. M.C. et aI .: British. Journal orCanccr 4) : 72 (Jan 1981)

6 INPHARMA 2 May 198\ 0156-2703/ 81 / 0502-0006 $00.50/ 0 C AOIS Press