Fertility preservation does not worsen breast cancer outcomes

The results held true both for women who did and didn't have hormonal stimulation alongside their procedures to collect eggs, in a retrospective nationwide cohort study of women with breast cancer in Sweden.

'It is not unusual that women with hormone-positive breast cancer or their treating doctors opt out of the procedures for fertility preservation because of the fear that these procedures will increase the risk of cancer recurrence or death,' said Anna Marklund, PhD researcher at the Karolinska Institutet, Stockholm, Sweden and first author of the study. 'In some cases, women are also advised to wait five to ten years before trying to conceive, and with increasing age, fecundity in all women decreases,' she continued.

Previous studies have not found additional risk to undergoing fertility preservation, but they have included a small number of patients and a short follow up time.

Working with data from 1275 women, the research team found no significant difference in the rate of disease-specific mortality between three groups of women. Those who underwent fertility preservation with exposure to hormones had a 96 percent survival rate at five years, compared to a 93 percent survival rate for women who underwent fertility preservation without hormone treatment, and 90 percent for those who did not undergo fertility preservation at all.

There was also no increased risk of recurrence of breast cancer either, with 89 percent of women who underwent fertility preservation with exposure to hormones not experiencing relapse, compared to 83 percent of women who underwent the procedure without hormones, and 82 percent who had not undergone fertility preservation. These differences were not found to be statistically significant.

The median follow-up time was four years for women with hormonal treatment, and almost seven years without. The group expects to follow up with the women again after five years.

'We did not see any increased risk of relapse or mortality when procedures for fertility preservation were undertaken,' said Professor Kenny Rodriguez-Wallberg, research group leader at the Karolinska Institutet. 'This is valuable information that can contribute to changed care routines when it comes to young women with breast cancer who want to preserve their fertility.'

The findings were published in JAMA Oncology.