Pregnant breast cancer patients more likely to survive

There may be few pregnancy nightmares worse than finding a lump in one’s breast, given the dueling fears that if it’s cancer, treatment could harm the developing fetus, while delay and pregnancy hormones could fuel a tumor’s growth. But a new study finds that pregnant women treated for breast cancer are more likely to survive their ordeal than breast cancer patients of the same age who were not pregnant when their cancer was diagnosed.

Five years after their diagnosis, almost 74% of the women diagnosed with breast cancer during pregnancy were still alive. Among their sisters who were not pregnant when they got treatment, 55.75% survived to the five-year mark. The researchers found some evidence that the pregnant breast cancer patients fared better on long-term survival, as well. But those findings were less clear than the difference in five-year survival.

The study’s findings, to be presented Friday at the American Society of Clinical Oncology’s Washington, D.C., meeting, are likely to help lay to rest the lingering belief that pregnancy is a uniquely dangerous time for a woman to discover breast cancer. Until very recently, a pregnant woman diagnosed with breast cancer would have been urged to terminate a pregnancy, or to wait until giving birth to begin aggressive treatment.

Texas researchers—including Dr. Richard L. Theriault, one of the authors of the current study--offered strong evidence in 1999 that breast cancer can be treated effectively during pregnancy without harm to the developing fetus. The result was a widespread shift in medical practice: a pregnant breast cancer patient now can expect to begin chemotherapy as soon as her first trimester is over, and resume treatment with radiation, follow-on chemotherapy or surgery after the baby’s birth.

The current study, which has yet to be published and is therefore considered preliminary, followed 225 women treated at M.D. Anderson Cancer Center in Houston between 1989 and 2009. Seventy-five of those women were diagnosed with breast cancer during pregnancy. The group’s survival was compared to 150 non-pregnant breast cancer patients who closely matched the pregnant group in age, date of diagnosis and the level of their cancer’s advancement.

Dr. Jennifer Litton of M.D. Anderson, who is to present the findings at the society’s 2010 Breast Cancer Symposium, said the babies born of the women who pioneered this shift are now 21. (And other research has found the rate of malformations or negative birth outcomes to be no higher for those treated with chemotherapy than those who were not.) She said researchers had dared hope for little more than to give pregnant breast cancer patients a shot at survival equal to that of women who were not pregnant at the time of diagnosis. To find that they fared better was extremely surprising, she said.

Litton said this news is of increasing importance, since more women are choosing to start or complete families later in life, thus boosting the likelihood that breast cancer and pregnancy will coincide. The finding has already led to research on how pregnancy may influence the growth of breast tumors, and whether pregnancy may somehow enhance the sensitivity of cancerous tissue to chemotherapy, Dr. Litton added.

--Melissa Healy/Los Angeles Times