4. Juni 2017

Reassuring results for breast cancer survivors who are contemplating pregnancy

Chicago, June 3, 2017 – Findings from a multicenter, retrospective study (abstract LBA10066) provide reassurance to breast cancer survivors who are contemplating pregnancy. In the study, women who became pregnant after an early breast cancer diagnosis, including those with estrogen receptor (ER)-positive tumors, did not have a higher chance of cancer recurrence and death than those who did not become pregnant.

About the study

The study included 1,207 women (333 pregnant and 874 non-pregnant), who were diagnosed with non-metastatic breast cancer before 2008, under the age of 50. The majority (57%) had ER-positive cancer, and more than 40 % had poor prognostic factors, such as large tumor size and cancer spread to the axillary lymph nodes. The median time from diagnosis to conception was 2.4 years. Women with ER-positive breast cancer tended to achieve pregnancy later than those with ER-negative disease; 23 % of patients with ER-positive disease had a pregnancy beyond 5 years from diagnosis as compared to 7 % in those with ER-negative tumors.
After a median follow-up of about 10 years from cancer diagnosis, there was no difference in disease-free survival between women who became pregnant and those who did not, irrespective of ER status. Secondary analyses showed that there was no difference in disease-free survival compared to women who did not become pregnant, irrespective of whether women completed the pregnancy or had an abortion, became pregnant less than two years or more than two years from breast cancer diagnosis, and whether patients had breastfed.

Among survivors of ER-positive cancer, there was also no difference in overall survival between women who became pregnant and those who did not. Survivors of ER-negative breast cancer who became pregnant had a 42 % lower chance of dying than those who did not become pregnant.
“It’s possible that pregnancy could be a protective factor for patients with ER-negative breast cancer, through either immune system mechanisms or hormonal mechanisms, but we need more research into this,” said lead study author Matteo Lambertini, MD, medical oncologist and ESMO fellow at the Institut Jules Bordet in Brussels, Belgium.

Although there was limited data on breastfeeding in this study (64 patients, with 25 women who reported having breastfed their newborn), the results suggest that breastfeeding is feasible, even after breast surgery.

“These data provide reassurance to breast cancer survivors that having a baby after a breast cancer diagnosis may not increase the chance of their cancer coming back. For many young women around the world who want to grow and expand their families, it’s very comforting news,” said Erica L. Mayer, MD, MPH, ASCO Expert.

Reference:
Lambertini M et al., abstract LBA10066: Safety of pregnancy in patients (pts) with history of estrogen receptor positive (ER+) breast cancer (BC): Long-term follow-up analysis from a multicenter study.

Source: ASCO press release, June 3, 2017