SAN ANTONIO – Early maternal and infant outcomes in a large German registry of women diagnosed with breast cancer during pregnancy argue in favor of treating breast cancer while continuing the pregnancy rather than resorting to early delivery by cesarean section in order to begin chemotherapy after the baby is born, according to Dr. Sibylle Loibl.
Dr. Sibylle Loibl
"Patients should be treated as closely as possible to standard recommendations for nonpregnant women," declared Dr. Loibl of University Women’s Hospital, Frankfurt.
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In this regard, the experience gleaned from the combined prospective and retrospective registry, which is supported by the Breast International Group and German Breast Group, supports newly published recommendations (Eur. J. Cancer 2010;46:3,158-68) issued by an international expert consensus panel of which Dr. Loibl was a member.
About 2% of all breast cancers are diagnosed during pregnancy. These are difficult cases that generate anxiety because of the need to weigh treatment of the mother and the interests of her developing child. With many women delaying childbirth until later in life, breast cancers in pregnancy may be increasing, according to Dr. Loibl.
The Breast Cancer During Pregnancy (BCP) registry to date includes 313 women with breast cancer of various stages and subtypes diagnosed during pregnancy. Forty-two percent of women were in their second trimester at the time of diagnosis, 23% were in the first trimester, and the rest were in the third.
Twenty-nine women miscarried or elected to have an abortion. Of the remainder, 49% were delivered by cesarean section. Half of women underwent mastectomy, and half had breast-conserving surgery, Dr. Loibl reported at the San Antonio Breast Cancer Symposium.
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A total of 142 women in the BCP registry underwent chemotherapy during pregnancy, and 118 others had chemotherapy after delivery. Patients who underwent chemotherapy during pregnancy were diagnosed with breast cancer at a median gestational age of 20 weeks, compared with 28 weeks for those who had chemotherapy after delivery.
Of note, 17% of women who underwent chemotherapy during pregnancy delivered before gestational week 35, compared with fully 33% of those who didn’t start chemotherapy until after delivery. The high rate of early delivery in the latter group was largely the consequence of a management strategy seeking to start chemotherapy as soon as possible without a fetus on board. But it’s well-established that preterm delivery carries a price in terms of infant morbidity – and the BCG registry data indicate there is no reason to go that route, according to Dr. Loibl.
Patients who underwent chemotherapy during pregnancy received a median of four cycles. Seventy-seven percent received an anthracycline-based regimen. Only six women received a taxane during pregnancy.
The median birth weight in babies in the chemotherapy-during-pregnancy group was 2,810 g, compared with 2,730 g in those for whom chemotherapy was delayed until after delivery.
Neonatal outcomes 4 weeks after delivery were similar in the groups with and without chemotherapy during pregnancy. However, there were three babies with congenital malformations in the chemotherapy-during-pregnancy group – one each of rectal atresia, hypospadias, and polydactyly – compared with one in the group not exposed to chemotherapy, although this difference wasn’t significant.
Median disease-free survival was closely similar in the two groups of women at 29 months. Session cochair Dr. Daniel F. Hayes of the University of Michigan, Ann Arbor, commented that these women had a strikingly poor prognosis with a high recurrence rate. Dr. Loibl said she and her colleagues think so, too, and plan to conduct a matched-pair outcomes comparison with a group of nonpregnant breast cancer patients of the same age, cancer stage, and treatment in order to look into this further.
One audience member rose to say he, for one, is quite worried about exposing a developing fetus to anthracyclines or taxanes, and that he’ll continue to feel that way until Dr. Loibl returns to San Antonio with reassuring follow-up data on the children at age 5 years and beyond.
"I would be one who in a patient diagnosed at 28 weeks would take her to week 34 and then deliver the baby, sparing the baby the rigors of chemotherapy until you show me it’s safe," he added.
Dr. Loibl replied that the limited longer-term follow-up data available thus far on children in the BCG registry show "nothing suspicious so far."
Further evidence in support of her point that premature delivery before commencing chemotherapy is unnecessary was provided in two other studies presented by Dr. Elyce Cardonick of the Robert Wood Johnson Medical School in New Brunswick, N.J.