ESMO Asia Virtual Congress 2020

Abstract 60P

Background

The bone is the most common site of distant metastasis from breast cancer that predisposes the patients for skeletal-related events (SREs) and often causes severe morbidity and poor quality of life. Identification of predilections and risk factors associated with bone metastasis and SREs is important in planning (neo)adjuvant treatment and surveillance systems particularly in a population of patients diagnosed in late stages such as in Indonesia and other developing countries.

Methods

Clinicopathological variables of breast cancer with intermediate to the high-high risk of recurrence were collected from a dataset in the Dr Sardjito Hospital, Indonesia. Risk factors affecting bone metastasis and SRE were then analyzed.

Results

Of 1081 non-metastatic breast cancer patients diagnosed from 2013 through 2018, 129 patients (11.9%) developed bone metastasis during a median follow up of 4.4 years. SREs occurred in 89 (68.5%) patients. In multivariable analysis, positive axillary lymph nodes (OR 2.189, p=0.002), early menopause (OR 2.020, p=0.030), luminal subtype (OR 1.811, p=0.003), advanced stage (OR 1.869, p=0.004), and having multiple metabolic comorbidities (OR 1.992, p=0.004) were significantly associated with risk of skeletal metastasis. Only positive lymph nodes, luminal subtype, and advanced stages were associated with higher SREs. Of 102 (82.2%) and 52 (40.3%) patients received bone-modifying agents and external radiotherapy, respectively.

Conclusions

The rates of bone metastasis and SREs are relatively high in breast cancer patients diagnosed in advanced stages. Our study suggests the importance of considering patients with high-risk of SREs and the need of treatment advancement to further prevent SREs in the care of breast cancer with bone metastasis.