Meta-Analysis Reassures Feasibility, Safety of Pregnancy in Breast Cancer Survivors

Although breast cancer survivors may have more difficulty in becoming pregnant and have a risk of preterm labor, compared to the general population, most deliver healthy babies and experience no detrimental effects on their long-term survival, according to a systematic review and 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 Eva Blondeaux, MD, in a presentation on this data.

Investigators set out to assess 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 to observe maternal safety, in terms of disease-free survival and overall survival. To do so, Blondeaux and her team reviewed the data of 39 studies. A total of 8,265,713 women were included in these studies, with 8,093,401 from the general population. Of the 114,573 BC patients, 7,505 had a pregnancy after diagnosis and 107,068 did not.

When evaluating the chances of pregnancy for breast cancer survivors, Blondeaux and her team compared data from 48,513 BC survivors to those of 3,289,113 women from the general population. A pooled analysis found BC survivors to have significantly lower chances of becoming pregnant when compared to the general population, at about 60% (95% Cl 0.32-0.49); p<0.001). When compared to other cancer survivors, only cervical cancer survivors had a lower chance of becoming pregnant, and overall, all survivors had a lower chance than the general population.

Investigators then compared the data of 3,240 BC patients to 4,814,452 women from the general population to evaluate reproductive outcomes. No differences were found in spontaneous and induced abortion, or pregnancy complications. There was a 14% increased risk for those women who survived BC to undergo a caesarean section, and a 50% higher risk for the child to be low in birth weight.

While BC 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.

In maternal safety, specifically disease-free analysis, 2,003 BC patients with post treatment pregnancy were evaluated, compared to 37,779 BC patients without post-treatment pregnancy. “The results showed no detrimental effect of pregnancy after breast cancer with a hazard ratio (HR) of 0.73, favoring patients with pregnancy after breast cancer,” said Dr. Blondeaux.

In the overall survival analysis, a total of 3,261 BC patients with post treatment pregnancy and 58,238 BC patients without post treatment pregnancy were included. As in the disease-free analysis, no detrimental effect was observed, with a HR of 0.56, also favoring patients with pregnancy after breast cancer.

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

Lastly, Blondeaux noted, 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 pregnancy 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.