Concerns about fertility often influence how young women with breast cancer approach treatment decisions and are a reason for forgoing or delaying hormone-blocking therapy, a new study by Dana-Farber Cancer Institute investigators shows.

The findings, published by the journal Cancer, reinforce the need for physicians to talk with patients about their fertility-related priorities and address them in treatment plans, the study authors write.

Such conversations are important not only at the start of treatment but during its entire course, as patients' goals and preferences may change over time.

"Young women with breast cancer face unique challenges, including issues surrounding fertility," says the study's lead author Tal Sella, MD, of Dana-Farber.

"For many premenopausal women with hormone receptor-positive breast cancer, long-term endocrine therapy [which blocks hormones that feed the cancer's growth] may prevent patients from having children while treatment is under way.

In this study, we explored the degree to which fertility concerns affect patients' decisions about receiving such therapy."

Young women with hormone receptor-positive breast cancer - which may grow in response to the hormones oestrogen or progesterone - are usually treated with surgery followed by chemotherapy and at least five years of endocrine therapy to prevent the cancer from recurring.

Endocrine therapy reduces the risk of recurrence by about 50%, research indicates, making it the most effective component of post-surgery (adjuvant) therapy.

For this study, researchers surveyed 643 participants in the Young Women's Breast Cancer Study---Principal Investigator: Ann Partridge, MD, MPH, of Dana-Farber) -- a multi-institutional study of more than 1,300 women at or under the age of 40 when diagnosed with breast cancer from 2006 and 2016.

The participants, all of whom had hormone receptor-positive, stage I-III breast cancer, were asked at the time of diagnosis about their medical history, current medications, fertility concerns, endocrine therapy decisions, among other subjects.

Follow-up surveys were conducted every six months for the next three years and annually after that.

During the first two years after diagnosis, one third of respondents indicated that fertility concerns affected their decisions regarding endocrine therapy.

Forty percent of those who reported these concerns chose not to start, or to discontinue, such therapy, compared to 20% of those without such concerns.

Of the women who expressed concerns and opted against or stopped endocrine therapy, 66% reported at least one pregnancy or pregnancy attempt during that two-year period.

Women who had had children before their diagnosis were less likely to express that concerns affected their endocrine therapy decisions than those who were childless.

These findings will be helpful in conjunction with those of the POSITIVE trial, which is examining whether it is safe for young women with breast cancer to take a break from endocrine therapy in order to have a child.

Results of the trial are expected within the coming years.

"Our findings shed new light on the dilemma facing many young women with hormone receptor-positive breast cancer: whether to optimise adjuvant treatment or fulfill their desire for children in the near term," says Dana-Farber's Shoshana Rosenberg, ScD, MPH, the new study's senior author.

"Physicians can best help their patients by understanding their goals and developing treatment strategies that incorporate their needs."

Source: Dana-Farber Cancer Institute