Young women who have completed treatment for invasive breast cancer often ask if a pregnancy will increase their chances of recurrence (cancer return). The question seems appropriate to me, especially given the fact that hormon receptor positive breast cancer is fueled by estrogen. It should be comforting to these women that a new study suggests that a pregnancy after treatment for early stage, estrogen receptor (ER-positive breast cancer does not affect the recurrence rate (Journal of Clinical Oncology 2013;31:73-79). Researchers in Brussels, Belgium aimed to compared the disease free survival (DFS) in pateitns with ER-positive breast cancer both with and without a subsequent pregnancy. The authors also looked at a number of other outcomes, including disease free survival among ER-negative patients.
The retrospective review found no difference in DFS between the pregnancy and non-pregnancy groups in the ER-positive group. Perhaps surprisingly, the patients who became pregnant less than 2 years after diagnosis had a better disease free survival compared to their matched controls. This last observation may be due to selection bias, I think. The bottom line? This study provides good evidence that a woman who desires a biological child after breast cancer diagnosis will not have their prognosis adversely affected by pregnancy. The study is not without flaws however, including the fact that 80% of patients had no information about a critical marker known as HER-2.
A big question is what to do if you want to become pregnant, but have not completed a recommended course of anti-estrogen therapy such as tamoxifen. Researchers are beginning to investigate the impact of a break from tamoxifen on results. I hope you have found this blog informative, and look forward to offering an e-book on breast cancer (for IPad) within weeks. I’m Dr. Michael Hunter, and I thank you for visiting with me.