The Evolving Role of Bone-Conserving Therapy in Patients With Breast Cancer

Breast cancer survivorship symptom management: current perspective and future development

Increasing numbers and longevity of cancer survivors has furthered our insight into the factors affecting their health outcomes, suggesting that multiple factors play a role (e.g., effects of cancer treatments and health behaviors). Emotional and physical symptoms may not always receive sufficient attention. In this short narrative review highlighting recent literature, we describe the most common physical and emotional symptoms of breast cancer survivors aged 50 years and older and outline a multidisciplinary symptom management approach, regardless of symptom etiology.

Denosumab and the current status of bone-modifying drugs in breast cancer

BACKGROUND

Bone-modifying therapy is a primary research interest in breast cancer. Several features contribute to the importance of the bone environment in the management of breast cancer. Firstly, bone metastases represent the most common site of breast cancer metastases and secondly, the emergence of cancer treatment-induced bone loss (CTIBL) among breast cancer survivors and patients is of increasing concern. Furthermore, concordant with the "seed and soil" theory, agents that alter the bone microenvironment may even prevent tumor cell seeding in bone and limit cancer growth.

MATERIAL AND METHODS

Medical databases and conference proceedings were searched to identify articles, abstracts and clinical trials that have or are investigating denosumab and bisphosphonates in cancer therapy. Our search included a predefined focus on bone-modifying therapies in early and advanced breast cancer.

RESULTS AND DISCUSSION

Bisphosphonates (BPs) have an established role both in the prevention and treatment of CTIBL and have been studied in the adjuvant setting for early breast cancer (EBC). Denosumab is a monoclonal antibody directed against RANK ligand and thereby inhibits osteoclastogenesis and bone resportion. It is the newest agent approved for the treatment of postmenopausal osteoporosis and the prevention of skeletal-related events (SRE) in cancer patients with solid tumors and bone metastases. Denosumab has a favorable toxicity profile in comparison to BPs and has the potential to improve cancer outcomes.

CONCLUSION

This review examines the existing role of denosumab in the treatment of bone complications of breast cancer and its potential role as adjuvant therapy.

Bisphosphonates: prevention of bone metastases in breast cancer

Disease recurrence and distant metastases remain challenging for patients with breast cancer despite advances in early diagnosis, surgical expertise, and adjuvant therapy. Bone is the most common site for breast cancer metastasis, and the bone microenvironment plays a crucial role in harboring disseminated tumor cells (DTCs), a putative source of late relapse in and outside bone. Therefore, agents that affect bone metabolism might not only prevent the development of bone lesions but also provide meaningful reductions in the risk of relapse both in bone and beyond. Bisphosphonates bind to mineralized bone surfaces and are ingested by osteoclasts, wherein they inhibit osteolysis, thereby preventing the release of growth factors from the bone matrix. Therefore, the bone microenvironment becomes less conducive to survival and growth of DTCs and bone lesion formation. Recent trials of zoledronic acid in the adjuvant setting in breast cancer have demonstrated reduced disease recurrence in bone and other sites in premenopausal and postmenopausal women with early breast cancer. Based on the proven effect of bone protection during adjuvant endocrine therapy, new treatment guidelines recommend the routine use of bisphosphonates to prevent bone loss during adjuvant therapy, which may likely become the standard practice.