Doctor Jennifer Litton, assistant professor in MD Anderson's Department of Breast Medical Oncology, presented the findings in a poster discussion session.
"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. "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."
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 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.
MEDICA.de; Source: University of Texas M. D. Anderson Cancer Center