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, MD, 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,” Litton, the study’s first author, stated in a press release.
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 to 2008, and were matched based on stage, age and year of diagnosis. Women who gave birth within 1 year of diagnosis were excluded from the comparison group.
All received the standard chemotherapy regimen 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 5-year disease-free survival of 73.94% in pregnant women, compared to 55.75% in the non-pregnant patients. Although not statistically significant, overall survival was also higher in the cases than the controls: 77.42% and 71.86%, 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,” Litton stated. “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, Litton explained, and understanding their findings is of research priority.