# Association between Extract Rheum rhaponticum 731 (ERr 731) prescription and subsequent breast cancer

## TL;DR

A long-term study found no increased breast cancer risk in women using ERr 731, a herbal extract for menopausal symptoms, compared to non-users or hormone therapy users.

## Contribution

This study provides real-world evidence that ERr 731 is not associated with increased breast cancer risk compared to non-users and HRT users.

## Key findings

- ERr 731 was not associated with increased breast cancer risk compared to non-users (OR: 1.01, 95% CI: 0.81–1.26).
- ERr 731 showed no increased risk compared to HRT users (OR: 0.96, 95% CI: 0.69–1.33).
- No associations were found in age-stratified or disorder-specific analyses.

## Abstract

The special extract ERr 731 from the roots of rhapontic rhubarb has been prescribed for women with menopausal symptoms for more than 30 years. The aim of the present study is to evaluate the association between ERr 731 therapy and subsequent breast cancer in women in a real-world setting. ERr 731 users were compared to women without this therapy as well as women receiving hormone therapy.

This retrospective cohort study included data of women treated by 260 office-based gynecologists in Germany who received a prescription for ERr 731 between 1993 and 2022 (IQVIA Disease Analyzer database). These women were matched to women without ERr 731 prescriptions as well as women with hormone replacement therapy (HRT) prescriptions (1:3) using nearest neighbor propensity scores. A univariate Cox regression analysis was conducted to evaluate the associations between ERr 731 prescription and breast cancer risk compared to women without ERr 731 prescription and women with HRT prescriptions.

A total of 5,686 women with versus 17,058 women without ERr 731 prescription were available for the first analysis, and 2,616 women with ERr 731 prescription (a proportion of the 5,686 women used in the first analysis) and 7,848 women with HRT prescriptions for the second (average age 52–53 years). ERr 731 was not associated with an increased risk of breast cancer diagnosis when the group of women with ERr 731 prescription was compared to women without (OR: 1.01, 95% CI: 0.81–1.26) or to that of women with HRT prescription ((OR: 0.96, 95% CI: 0.69–1.33). No associations were observed in age-stratified analyses or in women with and without menopausal or other perimenopausal disorders.

The present study provides strong evidence that ERr 731 is not associated with an increased risk of breast cancer diagnosis compared to both non-users and HRT users. Given its favorable safety profile, ERr 731 may represent a viable alternative to HRT, particularly for women concerned about breast cancer risk.