Pregnancy after certain breast cancers safe

Women who have had early-stage breast cancer and become pregnant do not have a greater chance of recurrence and death than those who do not get pregnant, according to results released Saturday from the largest study to ever explore the issue.

The study is the first to focus specifically on the safety of pregnancy for women whose cancers are fueled by estrogen. Researchers said their conclusions should allay concerns among some doctors and patients that pregnancy, which results in a surge in estrogen levels, could put these women at risk by encouraging the growth of any cancer cells that might remain in the body after treatment.

“Over the long term, having a pregnancy is safe,” said lead study author Matteo Lambertini, an oncologist at the Institut Jules Bordet in Brussels. “We were very happy to see that.”

The retrospective study involved 1,200 women in Massachusetts and across Europe who were followed for a decade. Almost 60 percent of the women had estrogenreceptor-positive cancer. The results were presented as an abstract at the annual meeting of the American Society of Clinical Oncology in Chicago.

In a 2013 article in the Journal of Clinical Oncology, the same researchers reported their five-year findings: Pregnancy did not increase the risk of a cancer recurrence. But they decided it was important to follow the patients over a longer time, and, as they reported Saturday, the 10-year results showed no difference in recurrence.

The women in the study were diagnosed under the age of 50 and before 2008; in no cases had the cancer spread beyond the breast. The researchers matched each patient who became pregnant with ones who did not but had similar tumor and treatment characteristics. The median time from diagnosis to conception was 2.4 years.