Fertility preservation may improve pregnancy outcomes for women with breast cancer
Fertility preservation at the time of breast cancer diagnosis appeared associated with a significantly higher likelihood of live births after diagnosis among Swedish women with breast cancer, according to study results in JAMA Oncology.
Researchers also observed a significantly higher rate of assisted reproductive technology treatment use among women who underwent fertility preservation compared with women who did not prior to breast cancer treatment.
“Information about the possibilities of having children after breast cancer treatment, with or without fertility preservation, is very important for women who suffer from breast cancer at reproductive age,” Anna Marklund, MD, PhD student in the department of oncology-pathology at the Karolinska Institute in Stockholm, said in a press release. “We hope that the conclusions of our study can increase the body of knowledge so that more women with breast cancer who want to have children can make informed decisions in consultation with their doctors.”
Marklund and colleagues conducted the Swedish nationwide cohort study to assess the long-term reproductive outcomes of 425 women with breast cancer who underwent fertility preservation at Swedish university hospitals between 1994 and 2017. They also sampled a matched control group of 850 women with breast cancer and no history of fertility preservation.
Researchers used population-based registers to analyze data on use of assisted reproductive technology, live births and mortality between January and September 2020.
Primary outcomes included HRs of live births and assisted reproductive technology treatments after breast cancer diagnosis among women with vs. without fertility preservation and cumulative incidence of these events in the presence of the competing risk for mortality.
Women who underwent fertility preservation experienced lower parity (nulliparous, 71.1% vs. 20.1%) than those in the control group and were younger (mean age, 32.1 years vs. 33.3 years), more likely to be diagnosed with ER-positive tumors (68% vs. 60.6%) and more likely to be scheduled to undergo chemotherapy (93.9% vs. 87.7%).
Results showed 22.8% of women who underwent fertility preservation had at least one post-breast cancer live birth (mean follow-up, 4.6 years) compared with only 8.7% of women who did not undergo fertility preservation (mean follow-up, 4.8 years). Women who underwent fertility preservation had a more than twofold higher rate of live births after breast cancer diagnosis (adjusted HR [aHR] = 2.3; 95% CI, 1.6-3.3).
The fertility preservation group also had a higher 5-year (19.4% vs. 8.6%) and 10-year (40.7% vs. 15.8%) cumulative incidence of childbirth than the control group.
Researchers additionally found that women who underwent fertility preservation had higher rates of assisted reproductive technology use (aHR = 4.8; 95% CI, 2.2-10.7) and lower rates of all-cause mortality (aHR = 0.4; 95% CI, 0.3-0.7) than the control population. Five- and 10-year cumulative incidence of mortality also favored women who underwent fertility preservation (5-year: 5.3% vs. 11.1%; 10-year: 13.8% vs. 23.2%).
The lack of data on childbearing intent or desire at the time of breast cancer diagnosis served as a potential limitation of the study, researchers noted.
“It is possible that desire, and not just the ability, to have children differed between the groups and that this, at least to some degree, explains the difference in childbirths. This is something that future research will have to expand on,” Kenny A. Rodriguez-Wallberg, MD, PhD, researcher in the department of oncology-pathology at the Karolinska Institute, said in the press release. “We can, however, draw the conclusion that fertility preservation in safe [for women with breast cancer] and that there is a link between this treatment and the probability of having children after breast cancer.”