Breast cancer remains the most common cancer in women in the United States. Experts estimated 287,850 breast cancer diagnoses in women in 2022. Further, breast cancer accounts for about 15% of cancer deaths among women. While most breast cancers occur in women over 50, about 9% of cases arise in women under 45 and about 5% in women under 40.
While relatively rare, breast cancers diagnosed in young women can have added complications. In addition to having higher odds of diagnosis at a late stage, breast cancer in young women are often highly aggressive and have few viable treatment options. In addition, young women with breast cancers can face unique concerns, including potential complications with fertility.
Hormonal therapies (also called endocrine therapies), which prevent the body from producing estrogen, can treat some types of breast cancer that require these hormones to grow. Oncologists utilize several hormonal approaches. One method blocks ovarian function by removing or radiating the ovaries, the body’s primary source of estrogen. Drugs known as luteinizing hormone-releasing hormone (LHRH) can temporarily suppress ovarian function by blocking the signals the body sends to tell the ovaries to produce estrogen. Other hormonal therapies can block the effects of estrogen. For example, selective estrogen receptor modulators (SERMs) prevent estrogen from binding to its receptors, inhibiting normal hormonal effects. Drugs called aromatase inhibitors can also target hormones by blocking estrogen production. These drugs inhibit the enzyme aromatase, which is required to produce estrogen.
The average age a woman tries to have a child has increased over time, and thus breast cancer may occur in a growing number of women before they have completed their reproductive plans. Some women concerned about fertility complications following breast cancer treatment may choose to delay or pause therapy to try to have a baby.
You might wonder if the decision to delay treatment for pregnancy impacts breast cancer outcomes. The good news is that data presented at the San Antonio Breast Cancer Symposium (December 6 – 10, 2022) suggests temporary delays in treatment don’t negatively affect short-term recurrence rates. The findings presented came from the “Pregnancy Outcome and Safety of Interrupting Therapy for Women With Endocrine Responsive Breast Cancer” (POSITIVE) clinical trial.
POSITIVE enrolled 518 women from 116 centers across 20 countries. The participants, all under age 43, wanted to become pregnant and opted to pause hormonal therapy for about two years to try to conceive and give birth. Before the treatment pause, the participants had 18 – 30 months of hormonal therapy.
With a median follow-up of 41 months, 44 women had experienced a breast cancer recurrence. The three-year recurrence rate of 8.9% mirrored that seen in a separate study, which included premenopausal women receiving hormonal therapy, revealing a 9.2% three-year recurrence.
POSITIVE followed pregnancy status in 497 women finding that 74% had at least one pregnancy and 63.8% had at least one live birth. This resulted in 365 births from a cohort of women highly concerned about fertility! These promising results may inform young women diagnosed with breast cancer, helping them make the best treatment decision for themselves and their families.