New findings from a federally funded phase III clinical trial, S0230/POEMS, indicate that adding a hormone suppressing drug called goserelin to standard chemotherapy may be an effective method of preserving fertility among women with early-stage hormone receptor-negative breast cancer.

In the study, women who received goserelin along with chemotherapy were 64 percent less likely to develop premature ovarian failure compared to women who received chemotherapy alone, and they were more likely to have successful pregnancies.

Survival was also improved among women in the goserelin arm: women were 50 percent more likely to be alive four years after starting chemotherapy compared to those in the standard arm.

“Preserving fertility is a common and important concern among younger women diagnosed with cancer, and these findings offer a simple, new option for women with breast cancer, or possibly other cancers,” said lead study author Halle Moore, MD, a staff physician at Cleveland Clinic in Cleveland, OH.

“Goserelin appears to be not only highly safe but also effective, as it increased the odds of becoming pregnant and delivering a healthy baby following chemotherapy.”

Ovarian failure (OF) – defined in this study as cessation of menstrual periods and postmenopausal levels of follicle-stimulating hormone (FSH)– is a common side effect of chemotherapy.

OF risk depends on the type and dose of chemotherapy as well as patient age and perhaps ovarian cycling (monthly development of eggs in ovaries) at the time of chemotherapy.

Goserelin and similar luteinizing hormone-releasing hormone (LHRH) analogues temporarily shut down ovarian function, essentially putting the patient into a postmenopausal state.

It is speculated that this protects follicles from chemotherapy damage.

These medications are widely used to control ovulation timing for infertility procedures, such as in vitro fertilization.

LHRH drugs are also widely used as hormonal therapies to treat advanced prostate and breast cancer.

In this study, 257 premenopausal women with stage I-IIIA hormone receptor-negative breast cancer were randomised to treatment with cyclophosphamide-containing chemotherapy alone (standard arm) or chemotherapy plus goserelin.

Goserelin was given as monthly injections starting one week before the first dose of chemotherapy.

Two years after starting chemotherapy, 8 percent of women in the goserelin arm had OF vs. 22 percent of women in the standard arm.

There was not a statistically significant difference in the number of women who reported attempting to conceive in the two arms.

Twenty-one percent of women (22 individuals) assigned to goserelin plus chemotherapy became pregnant, and only 11 percent (12 women) among those assigned to chemotherapy alone became pregnant.

These pregnancies resulted in 16 patients (15 percent of the group) delivering at least one baby on the goserelin arm compared with eight patients (7 percent) on the control arm.

An additional three patients on the goserelin arm and two on the standard arm had not had a documented delivery but were still pregnant at the time of data submission.

The study also found goserelin was safe – it was not associated with an increased risk of either miscarriage or pregnancy termination.

Researchers were surprised to find that goserelin also affected disease-free and overall survival.

After adjusting for disease stage, women in the goserelin arm were 50 percent more likely to be alive four years after starting treatment compared to those in the standard arm.

While these early results are very encouraging, Dr. Moore cautioned that more research is needed to understand any role of goserelin in the treatment of ER-negative breast cancer.

On the other hand, the POEMS findings do establish a role for LHRH analogues in preserving ovarian function and fertility prospects for women treated with curative intent chemotherapy for breast cancer.

Source: ASCO