Pregnancy poses no greater risk to breast cancer survivors, according to Belgian researchers.
They said their study indicated that pregnancy does not incur a greater risk of relapse for survivors of breast cancer.
“This study provides reassuring evidence on the long-term safety of pregnancy in breast cancer survivors”
The safety of pregnancy for women with history of breast cancer has remained a controversial topic for many years, especially in cases of oestrogen-receptor positive breast cancer, noted the researchers from the Institut Jules Bordet and Université Libre de Bruxelles.
In these cases, hormones can promote the growth and spread of breast cancer so, as hormone levels change during pregnancy, it was thought that cancer would be more likely to recur in survivors of oestrogen-receptor positive breast cancer during pregnancy.
The new study compared breast cancer survivors who became pregnant with those who did not become pregnant over an average period of seven years.
A total of 333 and 874 women were included in the pregnant and non-pregnant cohorts, respectively, of whom 56.8% had oestrogen-receptor positive breast cancer
The researchers tracked the recurrence rate of breast cancer and found that those who became pregnant did not experience a greater rate of recurrence, even in cases of oestrogen-receptor positive breast cancer.
They added that abortion, time to pregnancy, breastfeeding, and type of adjuvant therapy had no impact on patients’ outcomes.
They said: “This study provides reassuring evidence on the long-term safety of pregnancy in breast cancer survivors, including those with oestrogen-receptor positive disease.”
“This report provides long-term results of the largest study to date addressing the safety of pregnancy according to oestrogen-receptor status,” they said in the Journal of the National Cancer Institute.
“In addition, we provide for the first time subgroup analyses showing the lack of apparent detrimental effect of breastfeeding and type of adjuvant therapy on patients’ outcomes,” they said.
They added: “These results reinforce the notion that pregnancy should not be discouraged after breast cancer, even in women with history of oestrogen-receptor positive disease.”