Live birth after breast cancer may improve overall survival

Women who become pregnant and have a live birth following a diagnosis of breast cancer may have better overall survival (OS) outcomes than those without live births post-cancer, according to a study presented at ESHRE 2022.

“This analysis shows that having a baby after breast cancer doesn’t have a negative impact on survival,” said study author Professor Richard Anderson from the Medical Research Council Centre for Reproductive Health, University of Edinburgh, Scotland.

“OS was increased in women who had a live birth after breast cancer, including in those aged <30 [years] at diagnosis and without a previous live birth,” said Anderson and co-authors.

The authors used records from the Scottish Cancer Registry to identify women aged <40 years who were diagnosed with breast cancer between 1981 and 2017 (n=5,181). Pregnancies were included up to end 2018, with date of live birth being the study entry date.

A total of 290 women experienced a live birth following a breast cancer diagnosis. Each woman with breast cancer who had a live birth was matched with up to six control cases (no live birth) who had been diagnosed with breast cancer in a similar year and were alive at the time the matched patient had a live birth.

OS was improved among women who did vs did not experience a live birth following their breast cancer diagnosis (hazard ratio [HR], 0.65, 95 percent confidence interval [CI], 0.50–0.85; p=0.0015). [ESHRE 2022, abstract O-196]

Among women with a post-cancer live birth, this improved survival was apparent in women who had not been pregnant prior to their diagnosis of breast cancer (HR, 0.56, 95 percent CI, 0.38–0.82, p=0.003), but not among women who had been pregnant before breast cancer diagnosis (HR, 0.76, 95 percent CI, 0.53–1.09).

When breast cancer was assessed by stage, there did not appear to be a significant survival benefit following live birth regardless of whether the cancer was diagnosed at stage 1 (HR, 0.74, 95 percent CI, 0.40–1.35) or stage 2–3 (HR, 0.71, 95 percent CI, 0.37–1.37).

The effect of improved OS following a live birth varied by age, with the greatest effect noted in women aged 20–25 years at cancer diagnosis (HR, 0.30, 95 percent CI, 0.12–0.74; p=0.009), followed by those aged 26–30 years at diagnosis (HR, 0.58, 95 percent CI, 0.38–0.88; p=0.011). Live birth did not significantly affect OS in women aged 31–36 years or 36–39 years at diagnosis (HR, 0.67, 95 percent CI, 0.44–1.01; p=0.057 and HR, 0.89, 95 percent CI, 0.42–1.87; p=0.76, respectively).

Most women had a live birth within 5 years of breast cancer diagnosis (n=182), with OS increased in this group compared with those who did not have a live birth post-diagnosis (HR, 0.66, 95 percent CI, 0.49–0.89; p=0.006). Conversely, there was no OS benefit following live birth which occurred ≥5 years after cancer diagnosis (HR, 0.63, 95 percent CI, 0.36–1.13).

“As a hormone-sensitive cancer, there has long been concern among both patients and oncologists that having a subsequent pregnancy and live birth might impact recurrence and survival,” said Anderson and co-authors.

However, evidence on this is scarce with a lack of information on patient factors that may influence outcomes, they said.

“This is of growing importance given that age [of women during pregnancy] is increasing, so more women with breast cancer will not have started or completed their family,” they continued.

“[The results of this study provide] reassurance for the growing number of women who want to start or complete their families after breast cancer treatment,” Anderson concluded.