MONDAY, May 20, 2024 (HealthDay News) -- Fertility treatments such as in vitro fertilization (IVF) and other methods don't boost the odds for tumor recurrence in young women who've survived breast cancer and carry the BRCA cancer genes, a reassuring, new report finds.

The issue had been in question because breast tissue can be sensitive to hormones and many assisted reproductive techniques (ARTs) involve a temporary boost in estrogen.

However, the new Italian study "provides the first evidence" that fertility procedures are safe in women with those variants of the BRCA1 and BRCA 2 genes that are known to raise risks for breast and ovarian cancers, said study lead author Matteo Lambertini.

He spoke in a news release from the  European Society for Medical Oncology (ESMO). Lambertini's team presented its findings last week at ESMO's annual meeting in Lugano, Switzerland.

The new findings "provide reassuring evidence for these women and their doctors to consider when discussing the risks and benefits of using ART to preserve their chances of having a baby following completion of anti-cancer therapies,” said Lambertini, an associate professor of medical oncology at the University of Genova.

As the researchers explained, women in their reproductive years faced with a breast cancer diagnosis often opt to freeze their eggs, since some treatments can send them into early menopause. Doing so often involves boosting circulating levels of estrogen, however.

“We have previously been concerned that increasing hormone levels for fertility preservation techniques before starting breast cancer treatment may increase the risk of cancer recurrence in the future," Lambertini explained.

Investigating the issue, his team tracked 2000 to 2020 data on nearly 5,000 women with BRCA1/2 variants linked to cancer, all of who were diagnosed with breast cancer at the age of 40 or younger.

They compared the risk for a recurrence of breast cancer in 107 of these women who had a pregnancy using ART with 436 who conceived naturally. 

The result: Five years after successful conception, there was no difference in rates of recurrent breast cancer between the two groups.

There were also no differences in terms of complications from pregnancy.

The only difference found was that women conceiving with fertility treatments had more miscarriages and fewer induced abortions, compared to those conceiving naturally, the team found.

Lambertini noted that the study population was small, but that was a necessary evil: Breast cancer is rare in women under 40, and only about one in every six of those cases involve BRCA genes.

"We put together centers from all over the world to collect data on this unique group of patients,” he explained.

Study co-author Ann Partridge is professor of medicine at Harvard Medical School and vice chair of medical oncology at the Dana-Farber Cancer Center in Boston.

She said the new findings “provide reassuring evidence that pursuing fertility preservation before undergoing breast cancer treatment or using the products of fertility preservation [eggs or embryos] or undergoing fertility preservation after surviving breast cancer, all appear to be safe from a cancer standpoint and in terms of the baby’s outcome."

Because these findings were presented at a medical meeting, they should be considered preliminary until published in a peer-reviewed journal.

More information

Find out more about the BRCA genes at the U.S. National Cancer Institute.

SOURCE: European Society for Medical Oncology (ESMO), news release, May 16, 2024