# Efficacy of denosumab versus alendronate for aromatase inhibitor-associated osteoporosis in postmenopausal breast cancer patients: a retrospective analysis

## TL;DR

Denosumab was more effective than alendronate in improving bone density and reducing fractures in postmenopausal breast cancer patients on aromatase inhibitors.

## Contribution

This study provides a direct comparison of denosumab and alendronate for aromatase inhibitor-associated osteoporosis in breast cancer patients.

## Key findings

- Denosumab showed greater improvement in bone mineral density compared to alendronate.
- Denosumab was associated with a significantly lower incidence of vertebral compression fractures.
- Both treatments improved bone metabolism markers, but denosumab had better clinical outcomes.

## Abstract

Bisphosphonates and denosumab can increase bone mineral density (BMD) and are used to treat osteoporosis caused by aromatase inhibitors (AIs). However, few studies have been conducted on the effects of both on vertebral compression fractures (VCFs). This article aims to compare the effects of alendronate sodium and denosumab injection on the frequency of VCFs in postmenopausal women whose osteoporosis was brought on by AIs treatment for breast cancer.

A retrospective cohort study was conducted from January 2020 to December 2024, enrolling 121eligible breast cancer patients with aromatase inhibitor-associated osteoporosis from the orthopedic outpatient department of Foshan Hospital of Traditional Chinese Medicine. Patients were divided into two treatment groups: the alendronate group received oral alendronate sodium tablets (70 mg once weekly), while the denosumab group received subcutaneous denosumab injections (60 mg every 6 months). Both groups were supplemented with calcitriol and calcium carbonate/vitamin D3 tablets as baseline therapy. The observation period was 12 months. The following parameters were compared between the two groups before and after treatment: BMD, 25-hydroxy Vitamin D3 (25-OH D3), β-C-terminal telopeptide of type I collagen (β-CTX) and Procollagen I N-Terminal Propeptide (PINP), Visual Analog Scale (VAS) scores and Incidence of VCFs. Statistical analysis was performed using SPSS 27.0.

The study included a total of 121 patients. Post-treatment analysis revealed a significantly higher overall response rate in the denosumab group(n = 57) (91.22%) compared to the alendronate group(n = 64) (82.81%; P < 0.05). Notably, the denosumab group demonstrated superior outcomes in the following two areas: (1) significantly greater improvement in BMD, (2) lower incidence of vertebral compression fractures (both P < 0.05). Both treatment groups showed statistically significant improvements in bone metabolism markers following treatment (P < 0.01).

Both therapeutic regimens effectively improved BMD in the study population. However, comparative analysis revealed that denosumab injection (60 mg every 6 months) demonstrated significant advantages over weekly alendronate sodium (70 mg) in multiple clinical outcomes. Specifically, the denosumab group showed: (1) greater BMD improvement at all measured skeletal sites, and (2) a significantly lower incidence of VCFs (all P < 0.05) in postmenopausal women with aromatase inhibitor-associated osteoporosis.