Fertility Preservation Linked to Uptick in Live Births Following Breast Cancer

Survival after breast cancer is on the rise, thereby emphasizing the importance of these discussions that focus on fertility and reproduction among younger survivors. A recent study from Sweden, appearing in JAMA Oncology, investigated the long-term outcomes of fertility preservation among female survivor of breast cancer of reproductive age, finding they were more likely to have a live birth if they underwent FP and utilized assisted reproductive technology.

“Cryopreservation of oocytes and embryos after controlled ovarian stimulation is the standard strategy for fertility preservation (FP) in adult women. Until now, few studies have evaluated the long-term reproductive outcomes of FP in young women with BC,” the authors noted.

Their nationwide cohort study investigated the primary outcome of HRs for live births and assisted reproductive technology among 425 female breast cancers exposed to FP and 850 matched controls who were not, for a ratio of 1:2, respectively. The exposed group underwent FP at 1 of 7 Swedish university hospitals between January 1, 1994, and June 30, 2017.

The investigation found that more women in the exposed group had lower parity compared with the unexposed group: 71.1% vs 20.1%. These women were also younger, at a mean (SD) age of 32.1 (4.0) vs 33.3 (3.6) years for the unexposed group; had a higher rate of estrogen receptor-positive tumors, for 68.0% vs 60.6%; and had treatment schedules that included more chemotherapy treatments, at 93.9% vs 87.7%.

Additional analyses of the rate of live births among the exposed group resulted in higher numbers across the board compared with the unexposed controls:

• At least 1 post-breast cancer live birth: 22.8% vs 8.7%, with a mean 4.6-year follow-up
• A 2-fold higher rate of live births after the breast cancer diagnosis (hazard ratio [HR], 2.6; 95% CI, 1.9-3.5; adjusted HR [aHR], 2.3; 95% CI, 1.6-3.3)
• 5-year cumulative incidence: 19.4% (95% CI, 15.2%-24.6%) vs 8.6% (95% CI, 6.4%-11.4%)
• 10-year cumulative incidence: 40.7% (95% CI, 33.0%-49.5%) vs 15.8% (95% CI, 12.0%-20.7%)
• Significantly higher overall birth rate (aHR, 2.3; 95% CI, 1.6-3.3)
• Higher utilization of assisted reproductive technology (aHR, 4.8; 95% CI, 2.2-10.7)

Two measures were lower, however, but with positive implications: FP was linked to lower all-cause mortality (aHR, 0.4; 95% CI, 0.3-0.7) and 5-year cumulative incidence of death (5.3% [95% CI, 3.1%-9.0%] vs 11.1% [95% CI, 8.7%-14.1%]) in the exposed group.

Also in the exposed group, being nulliparous at diagnosis meant a 19% (95% CI, 14.2%-25.1%) 5-year cumulative incidence of live birth compared with 12.7% (95% CI, 7.6%-214.1%) seen in the exposed group. For those who had at least 1 child at diagnosis, the respective numbers were 20.2% (95% CI, 12.7%-31.3%) and 7.5% (95% CI, 5.3%-10.5%).

“Results of this nationwide cohort study indicate that although successful pregnancy after BC is possible both in women with and without FP, FP is associated with significantly higher rates of post-BC live births and use of [assisted reproductive technology] treatments, without any deleterious association with all-cause survival during a mean follow-up of 5.2 years,” the authors concluded. “These findings add to the current knowledge regarding FP treatments in women with BC.”

They believe their findings could enable oncologists and reproductive counselors to better initiate these conversations with their female patients who receive a breast cancer diagnosis.

Reference

Marklund A, Lundberg FE, Eloranta S, Hedayati E, Pettersson K, Rodriguez-Wallberg KA. Reproductive outcomes after breast cancer in women with vs without fertility preservation. JAMA Oncol. Published online November 19, 2020. doi:10.1001/jamaoncol.2020.5957