Having breast cancer is generally not a barrier to conceiving and giving birth, according to study findings to be presented at the upcoming American Society of Clinical Oncology Annual Meeting (ASCO 2024). The results underscore the need for accessible fertility preservation services, such as egg or embryo freezing, before commencing treatment.

“For many young women with breast cancer, the ability to have children following treatment is a major concern,” said Kimia Sorouri, MD, MPH, of Dana-Farber Cancer Institute. “Access to fertility preservation can help mitigate the damage from chemotherapy and other treatment,” she told reporters at a preconference media briefing. “This highlights the need for increased accessibility of fertility preservation services for women with newly diagnosed breast cancer who are interested in future pregnancy.”

Radiation, chemotherapy and hormone therapy can have side effects that negatively impact fertility. Further, many newer targeted therapies and immunotherapies have not been studied in women who are pregnant or trying to conceive. Few prior studies have looked specifically at women who tried to become pregnant after a breast cancer diagnosis, and existing research is limited by short follow-up times or exclusion of women with certain types of breast cancer.

This analysis, funded by Susan G. Komen and the Breast Cancer Research Foundation, included 1,213 participants in the Young Women’s Breast Cancer Study who were diagnosed with Stage 0 to Stage III cancer at ages 40 or younger between 2006 and 2016. Of these, 197 tried to become pregnant over a median follow-up period of 11 years.

The median age at diagnosis was 32 years, and three quarters were white. About 1 in 10 (13%) had inherited BRCA1 or BRCA2 genetic mutations that raise the risk for breast cancer. Half said they were “financially comfortable,” which was defined as having enough money left over to buy special things after paying bills. Half had never been pregnant before, and 72% had never given birth to a full-term infant; 15% reported fertility problems prior to their breast cancer diagnosis.

Most participants had Stage I (41%) or Stage II (35%) breast cancer, while 14% had ductal carcinoma in situ (Stage 0), an early noninvasive malignancy that some experts consider to be precancerous. Just 10% had more advanced Stage III cancer, and women with metastatic (Stage IV) cancer were not included. A majority (76%) had hormone receptor–positive breast cancer. In terms of treatment, 68% had received chemotherapy, and 57% had received hormone therapy within one year of diagnosis. Just over a quarter (28%) underwent fertility preservation procedures after diagnosis.

The study found that a large majority of participants who tried to become pregnant were able to conceive and give birth after receiving cancer treatment. About three quarters (73%) became pregnant at least once. The median time from cancer diagnosis to first pregnancy was four years. Nearly two thirds (65%) of those who attempted pregnancy—and 90% of those who actually got pregnant—gave birth to a live infant.

Women who were older at the time of breast cancer diagnosis were less likely to become pregnant and give birth, the study found. Those who were financially comfortable were more likely to become pregnant, and those who underwent fertility preservation after their cancer diagnosis were more likely to give birth. On the other hand, race and ethnicity, prior history of infertility, past births, BRCA mutations, breast cancer characteristics and type of cancer treatment did not significantly affect the chances of becoming pregnant or giving birth.

According to the researchers, this is the first prospective study that has more than 10 years of follow-up time and accounts for attempted conception, and it included patients with all subtypes of breast cancer. They intend to do longer follow-up to gain a better understanding of disease outcomes, such as survival, associated with pregnancy and birth, as well as subgroup analyses of women with estrogen receptor–negative breast cancer.

These results are encouraging, but they suggest that not everyone has access to the resources they need to become pregnant and give birth to a healthy baby.

“Evolving data continues to demonstrate not only the possibility but safety of pregnancy and live birth after breast cancer treatment,” Elizabeth Comen, MD, of Memorial Sloan Kettering Cancer Center, said in an ASCO news release. “This study indicated a significant number of breast cancer survivors attempting pregnancy achieved live birth, particularly those with financial comfort. All young patients interested in fertility preservation should have equitable access to preserve future fertility options.”

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