Study finds women treated for breast cancer while pregnant have improved survival
Long associated with a worse outcome, researchers at The University of Texas MD Anderson Cancer Center have discovered that women treated for breast cancer while pregnant, in fact, have improved disease-free survival and a trend for improved overall survival compared to non-pregnant women treated for the disease.
Jennifer Litton, M.D., assistant professor in MD Anderson's Department of Breast Medical Oncology, presented the findings in a poster discussion session at the 2010 Breast Cancer Symposium.
"Until now, older registry studies showed that breast cancer patients treated while pregnant had a worse outcome. However, in the past, these patients weren't always treated consistently with standard of care chemotherapy and often delayed their therapy until after delivery." said Litton, the study's first and corresponding author. "Given MD Anderson's experience in treating pregnant patients and our registry, we were able to look at these women treated by the same physicians, at the same institution, with the same standard of care."
In 1992, Richard Theriault, D.O., professor in the Department of Breast Medical Oncology, opened the first protocol examining a chemotherapeutic regimen for the management of these patients. He later published seminal studies proving that the regimen was safe for both pregnant mother and unborn child; it has since been adopted as the standard of care. MD Anderson has the oldest, active prospective registry in the world following the health of pregnant breast cancer patients and their children.
For the single institution, case-controlled study, Litton and her colleagues identified 75 women treated for breast cancer while pregnant. Using the institution's tumor registry and Department of Breast Medical Oncology database, the cases were compared to 150 non-pregnant breast cancer patients. Cases and controls were all treated at MD Anderson 1989 -2008, and were matched based on stage, age and year of diagnosis. Women who gave birth within one year of diagnosis were excluded from the comparison group.
All received the standard chemotherapy regimen - 5-fluorouracil, doxorubicin and cyclophosphamide (FAC); pregnant patients started therapy after completing their first trimester. Both groups received additional therapies as clinically indicated, with the pregnant women receiving those treatments after giving birth. The median follow-up was 4.16 years.
The researchers found a statistically significant five-year disease-free survival of 73.94 percent in pregnant women, compared to 55.75 percent in the non-pregnant patients. Although not statistically significant, overall survival was also higher in the cases than the controls: 77.42 percent and 71.86 percent, respectively.
"From this data set and our study, we are not sure why our pregnant breast cancer patients had better outcomes than those who were not," said Litton. "Is there something biological in the milieu of pregnancy that changes the response to chemotherapy? Or were these patients treated more aggressively?"
The reasons for the disease-free and overall survival discrepancy are still unknown, said Litton, and understanding their findings is of research priority.
"MD Anderson has a long history of being at the forefront of treating pregnant women for breast cancer, and, through our research, we've found it safe for both mother and child, and ultimately developed the standard of care," said Theriault, the study's senior author. "Now, when we are counseling breast cancer patients who are pregnant, we can say that they should have every expectation that they will do as well as our non-pregnant patients, and that they should start their treatment in the second or third trimester without delay."