Breast Cancer Survivors May Have Difficulty Becoming Pregnant, But Have Healthy Babies and Experience No Impact on Long-Term Survival

Compared to women in the general population, women who survive breast cancer may have more difficulty becoming pregnant and have a higher risk of preterm labor, but most deliver healthy babies and experience no negative impact on their long-term survival, according to data from a meta-analysis presented at the 2020 San Antonio Breast Cancer Symposium.

“Results of this meta-analysis provide reassuring evidence on the feasibility and safety of conceiving in women with a prior history of breast cancer,” said lead investigator Dr. Eva Blondeaux in a virtual presentation of the data.

Because pregnancy after breast cancer diagnosis and treatment is a priority for many young women, and increasing evidence shows that pregnancy after cancer is feasible, Blondeaux and colleagues set out to provide updated and solid evidence on these issues by conducting an analysis in three areas:

• the chances of pregnancy in BC survivors compared to the general population and survivors of other cancers;
• the reproductive outcomes in this population, including complications, delivery outcomes, and fetal outcomes, and
• maternal safety, in terms of disease-free survival and overall survival.

Thirty-nine studies enrolling 8,265,713 women were included in this analysis, with 8,093,401 from the general population. Of the 114,573 patients with breast cancer, 7,505 had a pregnancy after diagnosis and 107,068 did not.

When evaluating the chances of pregnancy for breast cancer survivors, Blondeaux and colleagues compared data from 48,513 breast cancer survivors to those of 3,289,113 women from the general population. The data demonstrated that breast cancer survivors had a 60% lower chance of becoming pregnant compared to the general population. When compared to other cancer survivors, only cervical cancer survivors had a lower chance of becoming pregnant. Overall, all survivors had a lower chance of becoming pregnant than the general population.

Investigators then compared the data of 3,240 patients with breast cancer to 4,814,452 women from the general population to evaluate reproductive outcomes. There was a 14% increased risk for those women who survived breast cancer to undergo a caesarean section, and a 50% higher risk for the child to be low in birth weight.

While breast cancer survivors also had a 45% higher risk of going into preterm labor, the investigators found no significant increased risk of congenital defects or other pregnancy or delivery complications. Additionally, no differences were found in spontaneous and induced abortion, or pregnancy complications.

On the topic of maternal safety, specifically in a disease-free analysis, 2,003 patients with breast cancer who became pregnant after treatment were evaluated, compared to 37,779 patients with breast cancer who did not become pregnant following therapy. No detrimental effect of pregnancy after breast cancer was found. Similar findings were identified in the overall survival analysis, where 3,261 patients with breast cancer who were pregnant following treatment and 58,238 patients who were not pregnant after treatment were evaluated. As in the disease-free analysis, no detrimental effect was observed, also favoring patients with pregnancy after breast cancer.

These findings provide evidence for the feasibility and safety of pregnancy in breast cancer survivors, but as Blondeaux noted, the higher risk of fetal complications means those pregnancies need to be more closely monitored.

Additionally, Blondeaux said, the fact that pregnancy appears to have no long-term impact on survivorship highlights the fact that patients’ desires to become pregnant should be considered, as many women can successfully undergo breast cancer treatment and go on to deliver healthy babies.

“The lack of detrimental prognostic effect of pregnancy after breast cancer (irrespective of patient, tumor, treatment, and pregnancy features) strongly voices for the need of deeper consideration of patients pregnancy desire as a crucial component of their survivorship care plan and wish to return to a normal life,” Blondeaux concluded.

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