New research presented at the San Antonio Breast Cancer Symposium 2020 has found that although breast cancer survivors are less likely than the general public to get pregnant, they typically deliver healthy babies and have no adverse effects on their long-term health.

Investigators conducted a large meta-analysis of breast cancer survivors of childbearing age. As the average age for pregnancy has risen over time, the investigators noted that it has become more common for women to be diagnosed with breast cancer before having a child. Furthermore, many anticancer therapies that have reduced mortality from breast cancer can also have long-term toxic effects on the body, including potentially damaging fertility.

“With the availability of more effective anticancer treatments, survivorship has gained substantial attention,” said the study’s corresponding author, Matteo Lambertini, MD, PhD, in a press release. “Today, returning to a normal life after cancer diagnosis and treatment should be considered as a crucial ambition in cancer care. In patients diagnosed during their reproductive years, this includes the possibility to complete their family planning.”

The researchers conducted a systematic literature review of 39 studies that identified women who had been pregnant after a breast cancer diagnosis. They evaluated the studies to assess the frequency of post-treatment pregnancies in these patients, fetal and obstetrical outcomes, disease-free survival, and overall survival. In total, they gathered data on 114,573 patients with breast cancer.

Compared with women from the general population, patients who had gone through breast cancer had a 60% reduced chance of having a pregnancy. Notably, this analysis did not specifically capture the overall number of women who tried to conceive, so Lambertini said it is possible that some women did not try to have a child after their treatment was completed. Some studies included in the analysis did include such data, and Lambertini estimated that more than half of young women who tried to conceive did so.

The study also found that compared with women in the general population, breast cancer survivors had 50% higher risk of having a baby with low birth rate, a 16% higher risk of having a baby that was small for gestational age, 45% higher risk of preterm labor, and 14% higher risk of having a caesarean section. However, there was no significant increased risk of congenital defects or other pregnancy or delivery complications. The risks of low birth rate and small gestational age appeared to be largely restricted to women who had received prior chemotherapy.

Furthermore, pregnancy after breast cancer was not associated with poor patient outcomes. Compared with breast cancer survivors who did not have a subsequent pregnancy, those who did get pregnant had a 44% reduced risk of death and a 27% reduced risk of disease recurrence. When controlling for the “health mother effect,” which suggests that women who feel well and have good prognoses are the most likely to try to conceive, women who got pregnant had a 48% reduced risk of death and a 26% reduced risk of disease recurrence.

The analysis also indicated that pregnancy appeared safe across BRCA status, nodal status, previous chemotherapy exposure, the amount of time between breast cancer diagnosis and pregnancy, and pregnancy outcomes. Overall, Lambertini said the analysis showed that pregnancy after breast cancer was safe without negatively affecting patients’ prognosis.

“These findings are of paramount importance to raise awareness of the need for a deeper consideration of patients’ pregnancy desire as a crucial component of their survivorship care plan,” he said. “This starts with offering onco-fertility counseling to all newly diagnosed young breast cancer patients.”

First author Eva Blondeaux, MD, said the higher risk of delivery and fetal complications does suggest that physicians should more closely monitor pregnant breast cancer survivors compared with pregnant healthy women from the general population. However, she concluded that the overall findings and the lack of negative effects on survival indicate that many women can successfully go through pregnancy after a breast cancer diagnosis.

REFERENCE
Breast Cancer Survivors Are Less Likely to Get Pregnant, but Often Have Healthy Babies and Good Long-term Health [news release]. American Association for Cancer Research; December 9, 2020. https://www.aacr.org/about-the-aacr/newsroom/news-releases/breast-cancer-survivors-are-less-likely-to-get-pregnant-but-often-have-healthy-babies-and-good-long-term-health/. Accessed December 9, 2020.