In an accompanying editorial in The New England Journal of Medicine, Michael F. Greene, MD, Chief of Obstetrics at Massachusetts General Hospital, and Dan L. Longo, MD, Professor of Medicine at Harvard Medical School and Dana-Farber Cancer Institute, mentioned the low odds for both oncologists and obstetricians of treating a pregnant patient with cancer.

“All specialty providers find themselves in unfamiliar territory when cancer is diagnosed in a pregnant woman,” they wrote. Available data on outcomes in children exposed to chemotherapy are inconsistent and frequently lack critical information, they noted.

Drs. Greene and Longo concluded:

Overall these data [from Amant et al] should be reassuring to women who are facing a new diagnosis of cancer during pregnancies and to their families. Most important, although these women are more likely to deliver prematurely than are women without cancer, the cognitive development of their offspring will be similar to that of children of the same gestational age who were not exposed to maternal cancer and chemotherapy. Prudence continues to suggest avoiding cancer treatment in the first trimester; however, treatment in the second and third trimesters is likely to be best for both mothers and their offspring.

In correspondence with The ASCO Post, Dr. Greene added a cautionary note: “No one would suggest that it is safe for a fetus at any gestational age to be directly in the field of radiation therapy to the maternal pelvis.  As little as 50 to 100 cGy direct exposure of a fetus in the second or third trimester will result in microcephaly. No reasonable combination of diagnostic procedures would ever total 50 cGy, but radiation therapy employs a few thousand centigray. Fetal exposures resulting from scatter from modern radiation therapy directed to other regions of the body (not the pelvis) is likely to be trivial and did not result in obvious harm in this study.”  ■

Disclosure: Dr. Greene is an Associate Editor and Dr. Longo is Deputy Editor at The New England Journal of Medicine.

Reference

1. Greene MF, Longo DL: Cautious optimism for offspring of women with cancer during pregnancy. N Engl J Med. September 28, 2015 (early release online).