Increased delivery and fetal complications may occur for women and their offspring following breast cancer therapy, but no greater risks for congenital abnormalities were observed in a study presented during the 2020 San Antonio Breast Cancer Symposium. The analysis, which included data on 114,573 breast cancer patients, showed that breast cancer survivors were significantly less likely to become pregnant compared to the general public.
Those who did get pregnant, however, experienced no greater risk for detrimental long-term effects, such as cancer recurrence. In fact, many had better outcomes than those who did not get pregnant.
"Returning to a normal life after cancer diagnosis and treatment should be considered as a crucial ambition in cancer care in the 21st century for women in their reproductive years," said the study's first author, Eva Blondeaux, MD, medical fellow in oncology at IRCCS Ospedale Policlinico San Martino in Italy. "Pregnancy after breast cancer diagnosis and treatment is a priority for many young survivors."
With the average age of pregnancy advancing in recent years, more women are now being diagnosed with breast cancer before having a child. Further, many physicians remain concerned about potentially detrimental effects of pregnancy after breast cancer, particularly with the advent of anti-cancer therapies that have successfully reduced mortality but may have long-term toxic effects.
Study Details
In this study, Biondeaux and colleagues performed a systematic literature review up to January 31, 2020, with no language restrictions, to identify women who became pregnant after breast cancer diagnosis. The team assessed chances of pregnancy after breast cancer, reproductive outcomes, and maternal safety (disease-free outcome and overall survival).
Overall, some 39 studies were included in the analysis, including retrospective and prospective case-control and cohort studies. Among the 114,573 patients with breast cancer in this analysis, some 7,505 became pregnant after breast cancer diagnosis. Results showed that, compared to the general population, breast cancer patients had a 60 percent lower chance of having a future pregnancy compared to healthy women in the general population.
"Compared to patients with other cancers, only women with cervical cancer had lower chances of pregnancy," noted Biondeaux.
The study did not specifically capture the overall number of women who tried to conceive, so it is possible that some women did not try to have a pregnancy after treatment completion, according to the study's corresponding author, Matteo Lambertini, MD, PhD, Adjunct Professor in Medical Oncology at the University of Genova - IRCCS Policlinico San Martino Hospital.
Some studies included in the analysis did report such data, and Lambertini estimated that more than half of young women who tried to conceive did so. Also, some women who did not intend to conceive did get pregnant.
The study also compared potential delivery and fetal complications between breast cancer survivors and the general population. Their analysis found that breast cancer survivors had increased risk for delivery complications such as preterm delivery (OR 1.45, 95% Cl 1.11-1.88) and caesarean section (OR 1.14, 95% Cl 1.04-1.25).
Fetal complications included low birth weight (OR 1.50, 95% Cl 1.31-1.73) and small for gestational age (OR 1.16, 95%, Cl 1.01-1.33). The increased risk for low birth weight and small for gestational age appeared to be restricted mainly to women who had received prior chemotherapy.
"The higher risk of delivery and fetal complications, but not congenital abnormalities, particularly in women exposed to chemotherapy, calls for ensuring a close monitoring of these pregnancies," Biondeaux said.
Importantly, no significant congenital abnormalities or other pregnancy or delivery complications were observed such as spontaneous or induced abortion, gestosis, antepartum or postpartum hemorrhage.
Likewise, pregnancy after breast cancer treatment was not associated with a negative impact on maternal health. Interestingly, breast cancer patients who became pregnant following treatment had a better overall survival than breast cancer survivors who did not become pregnant.
Those who did get pregnant had a 44 percent reduced risk of death and a 27 percent reduced risk of disease recurrence than those who did not become pregnant. When controlling for the "healthy 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 percent reduced risk of death and a 26 percent reduced risk of disease recurrence.
No detrimental prognostic effects of pregnancy after breast cancer were observed in patients with hormone receptor-positive disease, while better outcomes were observed for those with hormone receptor-negative disease. The safety of pregnancy after breast cancer was observed irrespective of BRCA status, nodal status, previous chemotherapy exposure, pregnancy interval, and pregnancy outcomes.
"The lack of detrimental prognosis, effect of pregnancy after breast cancer, irrespective of patient, tumor, treatment and pregnancy features, strongly voices for the need of a deeper consideration of patients' pregnancy desire as a crucial component of their survivorship care plan and wish to return to a normal life," said Biondeaux. "This starts with offering onco-fertility counseling to all newly diagnosed young breast cancer patients."
Warren Froelich is a contributing writer.