Childbirth and breast cancer prognosis

Abstract

Although certain risk factors for breast cancer incidence may also effect survival, findings have been inconsistent and the long-term role of childbirth is unknown. We studied the influence of number and timing of births on breast cancer prognosis prospectively. From 1958 to 1997, altogether 32,003 women, born 1932 or later, were notified to the Swedish Cancer Registry due to a primary invasive breast cancer. We obtained information on dates of all childbirths and achieved complete follow-up through 1997 by means of linkage to other nation-wide databases. Proportional hazards analyses were used to compute crude and multivariate hazard ratios (HR) with 95% confidence intervals (CI) of dying from breast cancer. We found a successively worse prognosis for women with a shorter delay between their last birth and breast cancer diagnosis (p for trend <0.0001). Compared to women with their last birth more than 10 years before diagnosis, the multivariate HR of breast cancer death was 1.39 (95% CI 1.17-1.67) for those with breast cancer diagnosis in the 3rd year after last birth and 1.72 (CI 95% 1.42-2.09) for those with diagnosis within 1 year after last birth. This adverse effect on prognosis of childbirth persisted beyond 10 years among women with a first birth before the age of 20 years. A pregnancy has marked adverse effects on the prognosis of a breast cancer diagnosed within 10 years after delivery. These findings suggest that pregnancy influences tumor biology.

Placental Weight and Breast Cancer Survival in Young Women

“…In some studies, low age at first childbirth has been associated with poorer prognosis (26,27), whereas other investigators have found no such association (12,25). Likewise, some (10,27), but not all (5,12,25,26) studies have found evidence of a worse prognosis with increasing parity. Most widely studied is the prognostic influence of time since last childbirth.…”

“…Most widely studied is the prognostic influence of time since last childbirth. Several studies have found a reduced survival among women who are diagnosed within 2 years from last childbirth (6)(7)(8)(9)(10)(11)(12), or during pregnancy (5,6,8), and to some extent, as long as 5 years (27), 8 years (6), or 10 years (5) after last childbirth, compared with those with less recent births.…”

“…Pregnancyassociated breast cancer has several definitions in the literature, mainly depending on the scope of the study. In this context, the period of interest was during pregnancy or within 2 y thereafter, as this is the period, which has most frequently been associated with reduced breast cancer survival (5)(6)(7)(8)(9)(10)(11)(12). Further categories were made as 2 to 5, 5 to 10, and z10 y.…”

“…Among women with premenopausal breast cancer, >40% die from their disease within 15 years from diagnosis (4). The prognosis is poorer among women diagnosed within 10 years after last delivery (5), and even poorer among women with pregnancy-associated breast cancer, defined as breast cancer diagnosed during pregnancy or within 2 years after delivery (5)(6)(7)(8)(9)(10)(11)(12). The underlying mechanisms for an adverse effect of recent childbirths on survival remain unclear, but hormonal influences may play a role.…”

Evaluation of Survival Rate and Pattern of Risk Factors and Recurrence Rate in Patients with Triple-Negative Breast Cancer with other Subtypes

“…Not even the frequency distribution of the first gestational age groups was significant in the different subgroups. In this regard, some studies reported no relationship between pregnancy and prognosis and the survival rate of patients with breast cancer (12)(13)(14)(15)(16). Conversely, some reports were based on the relationship between the survival rate of patients and their pregnancy status and the first gestational age (17,18); these studies suggested that pregnancy was effective at increasing the survival of breast cancer patients.…”