(HealthDay News) — For women diagnosed with early breast cancer during pregnancy, chemotherapy seems acceptable for both mother and infant, with most adverse effects relating to premature birth, according to a study published online Aug. 16 in The Lancet Oncology.
Sibylle Loibl, M.D., from the German Breast Group in Neu-Isenburg, and colleagues recruited 413 women (median age, 33 years) with a primary diagnosis of breast cancer during pregnancy (median gestation age at diagnosis, 24 weeks) to examine the safety of breast cancer treatment.
The researchers found that 48 percent of the women received a median of four cycles of chemotherapy during pregnancy, with most receiving an anthracycline. Chemotherapy impacted birth weight, after adjustment for gestational age (P = 0.018), but number of chemotherapy cycles did not (P = 0.71). There was no significant difference between the groups for preterm deliveries before 37 weeks of gestation. Side effects, malformations, or newborn complications were noted in 10 percent of infants and were significantly more common among infants born before 37 weeks of gestation, compared with those born in or after week 37 (16 versus 5 percent). Adverse events were significantly more common among infants exposed to chemotherapy in utero versus unexposed infants (15 versus 4 percent). Two chemotherapy-exposed infants who were delivered prematurely died but the deaths were thought to be unrelated to treatment. The median disease-free survival was 70.6 months for women who started chemotherapy during pregnancy and 94.4 months for those who started after delivery (P = 0.539).
“Because preterm birth was strongly associated with adverse events, a full-term delivery seems to be of paramount importance,” the authors write.