Nov. 2, 2010 (San Diego) -- Despite fears to the contrary, women who get pregnant after receiving radiation treatment for early breast cancer are not at increased risk of having their cancer come back, a new study suggests.
Pregnancy and Risk of Breast Cancer Recurrence
Although several studies have suggested a neutral or even beneficial effect of pregnancy on recurrence rates in women who receive radiation, there have been fears that the increased levels of hormones during pregnancy might stimulate tumor growth, Phillip Devlin, MD, a radiation oncologist at Harvard Medical School, tells WebMD.
"This study does not support those fears," says Devlin, who was not involved with the work.
The findings were presented here at the 52nd Annual Meeting of the American Society for Radiation Oncology.
Timing of Pregnancy
For the study, the researchers reviewed the medical records of women treated for early breast cancer between 1961 and 2005 at their institution. The average age of the women was about 28, and ranged from 19 to 30 years.
The women were treated with either breast-conserving surgery followed by radiation with or without chemotherapy and/or hormone therapy as needed or mastectomy. They were followed for an average of about 11 years, during which time about half of the patients had a recurrence.
Among the findings:
- Among women who became pregnant, the risk of recurrence was unaffected by the time of pregnancy, with those who conceived in the 12 months after diagnosis no more likely to have their cancer come back than women who got pregnant in later years.
- The choice of treatment only affected recurrence rates among women who did not get pregnant, Aljizani tells WebMD. Among these women, those who got breast-conserving surgery and radiation were 54% less likely to have their cancer come back, compared with those who had a mastectomy.
The analysis took into account other factors that affect the risk of recurrence, including whether the cancer had spread to the lymph nodes and choice of treatment, she says.
A drawback of the study is that the researchers looked back at the records of the women rather than following them over time, Devlin says.
"This means there are various biases. For example, it could be that women who didn't get pregnant were sicker and therefore at greater risk of recurrence," he says.
That said, it would be very difficult, if not impossible, to do a more robust study in which women are followed over time, Devlin says. "You can't predict who will get pregnant and who won't," he says.
Devlin says that at his institution, "we do not advise women not to become pregnant after radiation treatment."
"But many still have fears due to the hormones," he says. "We can use this research to reassure young women who have had radiation that they should not be worried about getting pregnant."
Radiation therapy does carry risks, Devlin says. That includes temporary skin reactions that are often compared to a bad sunburn in which the treated area becomes red and inflamed and the skin can peel or even blister.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.