Case Report on Treatment of Metastatic Breast Cancer with Trastuzumab during Pregnancy

The increasing number of pregnant breast cancer patients calls for a therapy that is as efficient as possible. After 10 years of collecting data on pregnant breast cancer patients in the German Breast Group (GBG), proposals for diagnostic measures and therapy regarding this special situation have been developed on the basis of 500 observed cases. Chemotherapy is regarded as safe from the 14th week of gestation on, but it is strongly advised not to use trastuzumab. Adverse outcomes for the newborn were predominantly observed in cases of early preterms. In our department, a 29-year-old second gravida with metastatic breast cancer first diagnosed 7 years ago continued to receive trastuzumab treatment at her express request after detailed information and advice. Trastuzumab treatment had been started 1.5 years before the pregnancy after surgical removal of a lymph node metastasis. After 7 intravenous administrations at intervals of 3 weeks, an oligohydramnios occurred in the 24th week of pregnancy. For this reason, trastuzumab treatment was interrupted for 7 weeks, during which time the quantity of amniotic fluid returned to a normal level. As the 8th administration of trastuzumab led to a renewed oligohydramnios, the trastuzumab treatment was suspended until birth. The quantity of amniotic fluid having recovered to normal, labour was induced after 36 weeks of pregnancy, followed by a Caesarian section because of prolonged labour. The newborn boy showed no sign of respiratory or renal dysfunction and has developed normally, having at present reached the age of 3 years. From the few reported cases of pregnancies with trastuzumab therapy, it seems that an occurring oligohydramnios is the typical complication with the problem of life-threatening RDS after birth. Probably the reduction of amniotic fluid can be reversed by interrupting the trastuzumab therapy, as we observed in our case.