Treatment of Cancer During Pregnancy: The Need for Tailored Strategies

TO THEEDITOR:Van Calsteren et al 1 recently reported a retrospective analysis of 215 patients with cancer who were diagnosed and managed during the course of pregnancy. They showed that managing patients with cancer during pregnancy is feasible and is not associated with an increased risk of fetal malformations. However,theauthorsstatedtheirconcernsregardingthehighincidence of preterm deliveries, which reached 54.2% in their series. They emphasized that preterm delivery is associated with high risk of medicalcomplications,whichcouldhaveseriousconsequenceson fetal morbidity and mortality. In an attempt to reduce this risk, they proposed delaying adjuvant therapy for patients with early breast cancer until fetal maturity, even if this would entail holding therapy up to 3 months. They referred to a mathematical model suggesting that delaying adjuvant therapy in gestational breast cancer could be an acceptable approach. 2 They also suggested that if chemotherapy is considered, delivery should be delayed until fetal maturity rather than fetal viability. We completely agree with the second proposition provided the proper selection of the agents administered during the course of gestation. Nevertheless, although we acknowledge that delaying adjuvant therapy for patients with breast cancer is reasonable in some cases, it remains questionable for many others as a result of the typically aggressive biology of gestational breast cancer. It has been shown that almost 50% of patients with breast cancer diagnosed during pregnancy are diagnosed with locally advanced, node-positivedisease. 3 Furthermore,delayingadjuvantchemotherapy beyond 3 weeks from surgery was shown to be detrimental in patients with endocrine unresponsive tumors. 4 Thus, chemotherapy should not be delayed in pregnant patients with breast cancer whoneedit.Theexceptionwouldbeforpatientsdiagnosedduring the first trimester, in which the incidence of fetal malformation is as high as 20%. 5 Of 83 patients diagnosed with gestational breast cancer, only six infants (7%) had a birth weight below the 10th percentile for gestational age. Other studies showed similar results as well. 6,7 Hence,itisnotclearthatpatientswithearlybreastcancerarethose at significant risk of preterm delivery if exposed to chemotherapy during the pregnancy course. We believe it is hard to generalize conclusions and caution should be taken when dealing with less aggressive settings (eg, adjuvant breast cancer), in which we could compromise their treatment for fear of a risk, which seems to be low anyway in their case. We have recently conducted a systematic review of literature on theuseofdifferentsystemictherapiesinthetreatmentofpatientswith