Neuroendocrine tumors and pregnancy: the French PregNET study

OBJECTIVE: The rising incidence of neuroendocrine tumors (NETs) and delayed motherhood raise concerns about pregnancy outcomes and management, yet data remain scarce. METHODS: This national cohort study, conducted through the GTE and RENATEN-ENDOCAN networks, included 17 women with NETs who experienced 26 pregnancies, resulting in 27 births. Maternal and fetal outcomes were analyzed based on tumor status, presence of carcinoid syndrome, and treatments during pregnancy. Early postpartum tumor evolution was evaluated using mRECIST on CT scans at 1 and 6 months after delivery. RESULTS: Median maternal age at first pregnancy was 31. Among women with resected localized NETs, 71.4% remained in remission post-pregnancy, while 28.6% experienced recurrence. In metastatic NETs, disease remained stable in 50% of cases, with 21.4% showing progression. Most progression was observed on 1-month postpartum scans. No worsening of carcinoid syndrome symptoms occurred. The overall cesarean rate was 16.7%, increasing to 25% in those with carcinoid syndrome. Live birth rates were high: 94.4% under surveillance and 91% under somatostatin analog (SSA) therapy. Intrauterine growth restriction rate was higher in patients receiving SSA therapy, while birth weight and length were not affected. No developmental issues were observed by age 2. CONCLUSION: Pregnancy is generally safe and successful in women with NETs. No major safety concerns were observed with SSA; however, these findings should be interpreted cautiously given the small sample size. Their use should remain individualized within a multidisciplinary approach, with early postpartum tumor assessment to optimize fetal and maternal outcomes.