Endocrine Abstracts

Introduction

Adjuvant endocrine therapy has an important role in the management of hormone receptor-positive (expressing oestrogen/progesterone receptors) early-stage breast cancer, reducing the risk of recurrence and improving associated mortality. The estradiol depletion produced by hormone therapy has detrimental effects on skeletal health, which can lead to low bone mineral density (BMD), altered bone microarchitecture and increased risk of fracture.

Methods

7 premenopausal patients with histologically proven hormone receptor-positive breast cancer, treated with luteinising hormone releasing hormone (LHRH) analogue goserelin were evaluated in our clinic. 6 of them were treated also with selective oestrogen receptor modulator tamoxifen and one patient was receiving aromatase inhibitor letrozole. All of the patients received adjuvant chemotherapy and all had secondary amenorrhea. Lumbar spine, total hip and femoral neck BMD and Z-scores along with lumbar spine trabecular bone score (TBS) were measured using dual energy x-ray absorptiometry (DXA GE Lunar). Bone turnover was assessed by measuring C-terminal telopeptide of type I collagen (CTx), osteocalcin (OC) and N-terminal propeptide of type I procollagen (P1NP).

Results

The mean age was 43.8 ± 3.5 years old and the mean duration of endocrine therapy was 2.3 ± 1.6 years. The mean lumbar spine and femoral neck BMD were 1.025 ± 0.13 g/cm² and 0.895 ± 0.15 g/cm², respectively. The mean Z-scores were –1.08 ± 5 sd at lumbar spine and –0.51 ± 0.4 sd at femoral neck region. 2 patients had a Z-score at lumbar spine below –2 sd and one of the patients was diagnosed with a vertebral fragility fracture using radiography. Therefore, the treatment with bisphosphonates, calcium and vitamin D was initiated. All other patients also received calcium and vitamin D supplementation. The mean TBS was 1.324 ± 0.08, 4 patients having a TBS < 1.350, suggesting a degraded bone microarchitecture. The mean P1NP, OC and CTx were 65.7 ± 28.4 ng/ml, 19.54 ± 5.95 ng/ml and 0.49 ± 0.25 ng/ml, respectively, indicating an increased bone turnover, demonstrated by the elevated serum CTx and P1NP levels (mean values). There was no significant difference regarding BMD and bone biomarkers in letrozole-treated patient compared to tamoxifen group.

Conclusion

This study emphasizes the importance of assessing bone health and regular follow-up in women undergoing hormone therapy for breast cancer, as it can lead to bone loss and degraded bone microarchitecture. Furthermore, prevention of fragility fractures can be obtained by calcium and vitamin D supplementation or antiresorptive therapy, whenever it’s necessary.