In a systematic review and meta-analysis reported in the Journal of Clinical Oncology, Matteo Lambertini, MD, PhD, and colleagues found that breast cancer survivors were less likely to have subsequent pregnancy vs the general population and more likely to have preterm birth. However, no reduction in competed pregnancies and no increased risk of maternal complications or congenital abnormalities were observed. Survivors with vs without subsequent pregnancy also had better survival outcomes.
A systematic literature search through October 2020 identified 39 retrospective or prospective case-control or cohort studies and clinical trials reporting on pregnancy after breast cancer that had information available on one or more of the three outcomes of interest: likelihood of pregnancy after breast cancer, reproductive outcomes, and maternal safety.
These results provide reassuring evidence on the safety of conceiving in breast cancer survivors. Patients’ pregnancy desire should be considered a crucial component of their survivorship care plan.— Matteo Lambertini, MD, PhD, and colleagues
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The 39 studies included 8,093,401 women from the general population and 112,840 breast cancer survivors; of the survivors, 7,505 had a pregnancy after diagnosis.
Breast cancer survivors were significantly less likely to have a subsequent pregnancy compared with the general population (relative risk [RR] = 0.40, 95% confidence interval [CI] = 0.32–0.49).
Risks of caesarean section (odds ratio [OR] = 1.14, 95% CI = 1.04–1.25), low birth weight (OR = 1.50, 95% CI = 1.31–1.73), preterm birth (OR = 1.45, 95% CI = 1.11–1.88), and the baby being small for its gestational age (OR = 1.16, 95% CI = 1.01–1.33) were significantly higher in breast cancer survivors vs the general population. In a subgroup analysis, increased risk of low birth weight and being small for gestational age appeared to be restricted to breast cancer patients with previous exposure to chemotherapy.
No significant differences between breast cancer survivors and the general population were observed for completed pregnancies (OR = 1.21, 95% CI = 0.48–3.03), spontaneous (OR = 1.04, 95% CI = 0.86–1.26) or induced abortions (OR = 1.40, 95% CI = 0.71–2.76), pre-eclampsia (OR = 1.03, 95% CI = 0.27–3.98), postpartum bleeding (OR = 0.88, 95% CI = 0.57–1.37), or risk of congenital abnormalities (OR = 1.63, 95% CI = 0.89–2.98).
Breast cancer survivors with vs without subsequent pregnancy had improved disease-free survival (hazard ratio [HR] = 0.66, 95% CI = 0.49–0.89) and overall survival (HR = 0.56, 95% CI = 0.45–0.68).
The investigators concluded, “These results provide reassuring evidence on the safety of conceiving in breast cancer survivors. Patients’ pregnancy desire should be considered a crucial component of their survivorship care plan.”
Dr. Lambertini, of IRCCS Ospedale Policlinico San Martino and the University of Genova, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the Italian Ministry of Health and Italian Association for Cancer Research. For full disclosures of the study authors, visit ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.