How effective is hormonal therapy for patients with hormone receptor positive early breast cancer?

This study examined the effectiveness of hormonal therapy in premenopausal women with hormone receptor-positive early breast cancer with or without other treatments. The authors concluded that patients who received hormonal therapy had a higher chance of survival and without a return of cancer.

The hormone receptor (HR) is activated by estrogen or progesterone (female sex hormones) and this is one way that cancer increases its growth. Therefore, blocking HR is important in patients who are HR-positive. Hormonal therapy drugs block the production of estrogen and progesterone from the ovary. Ovary production of hormones can also be prevented by radiotherapy or surgery to remove the ovaries. All these methods are called ovarian suppression therapy (OST).

OST is usually offered to patients after they have completed another treatment to prevent cancer from returning. Depending on the patient, it may be offered alone or in combination with chemotherapy or other hormonal therapy drugs. It is unclear if it is beneficial to premenopausal patients with early HR-positive breast cancer.

The results of 15 studies were examined. Overall, 11,538 premenopausal women with HR-positive breast cancer were included. OST was added to either observational therapy, chemotherapy or tamoxifen (Nolvadex). Patients were observed for 5.3 to 12.1 years.

Overall, OST improved patients’ survival by 14%. OST improved survival by 17% compared to observational therapy. Survival increased by 26% when OST was added to tamoxifen and by 69% when it was added to chemotherapy and tamoxifen. When OST was added to chemotherapy, it modestly improved survival by 5%.

The type of OST affected survival results. Patients who received anti-estrogen drugs had a 20% improved survival rate. Patients who had their ovaries removed by surgery had a 14% improved survival rate. Radiotherapy did not improve patients’ survival.

Overall, hormone therapy also improved patients’ survival without signs of cancer by 17%. When it replaced observational therapy, survival without signs of cancer improved by 18%. When it was added to tamoxifen, survival without signs of cancer increased by 24% and by 31% when added to chemotherapy and tamoxifen. Hormone therapy increased survival without signs of cancer by 10% when added to chemotherapy.

The authors concluded that OST improves the survival of premenopausal patients with HR-positive breast cancer.

The studies included in this analysis had different setups and included different treatments, such as the type of chemotherapy.