Does Subsequent Pregnancy Influence Breast Cancer Survival

摘要

Although future childbearing decisions may impact the quality of life of young breast cancer patients, some oncologists are concerned that disease recurrence may be stimulated by hormonal elevations of pregnancy. This retrospective study is being conducted collaboratively with researchers of the Kaiser Permanente, an HMO with extensive medical records, to assess the prognostic effect of post diagnosis pregnancy. Linked datafiles enabled the identification of 114 cases <45 at diagnosis who had one or more subsequent pregnancies. Four comparison cases without a post-diagnosis pregnancy matched on stage, age and year of diagnosis were selected. To date 351 comparison cases have been identified. All cases were diagnosed in a Kaiser affiliated hospital between 1970 to 1995. Reported SEER tumor stage indicated 20% were in situ, 54% with local disease, and 26% with regional disease. Only 20% of those with a subsequent pregnancy were nulliparous at diagnosis; 56% of the subsequent pregnancies were carried to term, 10% were terminated by miscarriage and 32% by induced abortion. Data on disease recurrence and death is abstracted from medical records, California mortality files, and the National Death Index. Cox proportional hazards models will be used to risk of recurrence and death due to breast cancer by post diagnosis pregnancy history controlling for known prognostic factors.