Unveiling bone metastasis: Exploring histological subtypes of breast cancer in Indonesia's tertiary referral hospital

Introduction

The histological grade of a tumor is an important prognostic indicator in both primary breast cancer and metastatic. We aimed to show the distribution of bone metastasis locations across different histological subtypes of breast cancer and how they relate to each.

Methods

The cohort retrospective study comprised 65 patients diagnosed with bone-only metastatic breast cancer, all female. The secondary statistics for 2014 to 2022 were derived from breast cancer registration data collected to determine the relationships between patterns of bone metastases sites and histopathological grading in various histological categories.

Results

The average age was 44.28±9.80 years (25–62 years), with 38 patients (58.5%) diagnosed with Invasive Ductal Carcinoma (IDC) and 27 patients (41.5%) with Invasive Lobular Carcinoma (ILC). Grade III were found in 34 patients (50.8%), Grade II in 31 patients (47.7%) and Grade I in one patient (1.5%). The most common sites of bone metastases are costae, followed by femur, vertebrae and pelvic. Vertebrae and costae metastasis are significantly correlated with histological grading and breast cancer pathology (p: 0.027 and 0.033, respectively).

Conclusion

There is a considerable difference between vertebrae and costae metastasis in terms of histological grading and breast cancer pathology which indicates the higher grade contains a greater variety of bone metastases sites.