Chemotherapy, Radiation Safe During Pregnancy in Second or Third Trimester

Results from a new study provide reassurance to women with cancer during pregnancy that they can be safely treated during the second or third trimester with chemotherapy/radiation without compromising their unborn child. The study found that children born to mothers treated with chemotherapy/radiation during pregnancy had no impairment in general health, cognition, or cardiac function compared with children born to healthy mothers.^1,2 Women in the first trimester should not undergo chemotherapy or radiation, however, the study authors found.

This study was published online in the New England Journal of Medicine and coincides with a presentation at the 2015 European Cancer Congress (ECC 2015). Importantly, prematurity is associated with worse cognitive outcomes in general, but, in this study, cancer treatment during pregnancy resulted in no additive impairment in infants born prematurely.

“These results show that preterm delivery—but not cancer treatment—is associated with worse outcomes,” According to the lead author, Frédéric Amant, MD, University Hospitals Leuven, Belgium. “This suggests that we should no longer induce preterm delivery, and that it is safe to start cancer treatment while a woman is pregnant, except during the first trimester. We hope that with these data we can convince more oncologists around the world to treat cancer during pregnancy and avoid preterm delivery.”

Dr Amant and colleagues conducted a multicenter, case-control study and enrolled 129 children born to mothers who had cancer during pregnancy (prenatal-exposure group), and matched them 1:1 to 129 controls from the general population who were born to healthy mothers after uncomplicated pregnancies and deliveries.

A total of 96 children in the exposure group were exposed to chemotherapy alone or in combination with other treatments. Specifically, 11 women were exposed to radiation alone or in combination, 13 to surgery alone, and 2 to other drug treatments; 4 of these women had radiation and surgery, and 7 had chemotherapy and radiation; 14 women were not treated until after delivery.

Sixty-one percent of children in the prenatal-exposure group were born preterm (ie, before 37 weeks of gestation), a higher rate than seen in the general population (approximately 8%). The number and type of congenital malformations were similar between cases and controls.

Investigators assessed general health of offspring, cognitive outcomes, and cardiac morphology and function. All children were tested at 18 months, and 48 children were tested at 18 months and 36 months.

Birth weight was below the 10th percentile (ie, small for gestational age) in 28 (22%) children in the prenatal-exposure group, and in 19 (15.2%) control children, a difference that was not statistically significant. Looking more closely, the rates of “small for gestational age” were 25% in children exposed to chemotherapy, and 36% in those exposed to radiotherapy, but 64% caught up in terms of weight at 18 months.

There was no difference between exposed children and controls in general medical health, which reflected the incidence of medical problems and need for surgery and/or medical care.

Assessment of cognitive outcome at a median age of 22 months using the Bayley Scales of Infant Development found no significant differences in cognition between the exposure group and controls, and no differences related to the number of cycles or type of chemotherapy (anthracyclines, taxanes, and platinum derivatives), or to the estimated fetal dose of radiation.

Cardiac function was assessed at 36 months in 50 of 54 children in the prenatal-exposure group using electrocardiography and echocardiography, with 47 children having sufficient data for evaluation. These children were compared with 47 matched controls for age and sex. No structural or functional cardiac abnormalities were seen in any of the exposed children, and there were no differences in cardiac measures between exposed children and controls.

Although heart function in the exposed babies was normal, Dr Amant recommended long-term monitoring for those whose mothers were treated with anthracyclines, which comprised a majority of women.

These findings cannot be extrapolated to newer targeted agents, Dr Amant noted.

References
1. Amant F. Cancer in pregnancy: the obstetrical, perinatal and pediatric point of view. Presented at: European Cancer Congress 2015; September 25-29, 2015; Vienna, Austria.
2. Amant F, Vandenbroucke T, Verheecke M, et al; International Network on Cancer, Infertility, and Pregnancy (INCIP). Pediatric outcome after maternal cancer diagnosed during pregnancy. N Engl J Med. 2015 Sep 28. Epub ahead of print.