Metastatic breast carcinoma confined to bone: portrait of a clinical entity

The current study was performed to study metastatic breast carcinoma that remains confined to bone.

The medical notes of 2514 breast carcinoma patients who were treated in 2 academic units over a 20-year period were screened and patients who fulfilled the following criteria were selected: 1) clinical manifestation and imaging confirmation of bone metastases, and 2) metastatic disease remaining confined to bone for a minimum of 24 months. Available clinical and pathologic data were recorded and analyzed. The objective of the current study was to describe this clinical entity and investigate possible correlations between clinicopathologic parameters and clinical outcome.

A total of 104 patients (4% of the total screened patient population) fulfilled the study criteria. The majority of patients were postmenopausal, with a median age of 58 years; 44 of the patients were found to have metastases at the time of presentation (M1) and 60 patients developed metastases at a median of 38 months (range, 8-160 months) after surgery for the primary tumor. Metastases remained confined to bone for a median of 50 months. Survival after the diagnosis of bony metastases was 72 months and was similar in the 2 groups (66 months vs. 78 months). Of the patients treated, 80% responded to hormonal therapy, and 76.5% responded to chemotherapy. There was no association noted between survival and tumor grade, anatomic distribution, or disease extension.

Bone-confined metastatic breast carcinoma has an indolent clinical course that alleviates the need for vigorous follow-up and calls into question aggressive therapeutic approaches in these patients. Translational studies are warranted to map the molecular profile, leading to the development of targeted therapies in this group of patients.