Bone metastases are common in breast cancer, with 69% of patients dying with breast cancer having skeletal metastases. Bone is the most common site of first distant relapse, more common in receptor-positive or well-differentiated tumors. Patients with disease confined to the skeleton have a median survival of 24 months, compared to 3 months after first relapse in the liver. Hypercalcaemia occurs in 10% of patients with breast cancer, often with widespread skeletal involvement. Response to treatment in bone is less than overall response, with many patients having static disease. Palliation of symptoms, control of disease, and evaluation of therapy are important. Bone metastases may be asymptomatic but can cause pain, hypercalcaemia, pathological fractures, and leuco-erythroblastic anaemia. Patients with bone metastases often have a long clinical course, with remissions and requiring palliative therapy. Assessing response to systemic therapy in bone is difficult, as UICC criteria require radiological evidence of healing, which may not be apparent for 4–6 months. The study analyzed 587 patients who died between 1979–1984 and 2240 patients with primary breast cancer. Bone was the most common site of first distant relapse, with 47% of all first distant relapses occurring in bone. Patients with first relapse in bone had a median survival of 20 months, compared to 3 months after first relapse in the liver. Tumor characteristics, such as hormone receptor status and histological grade, were compared between patients with first relapse in bone and liver. Bone metastases were more common in well-differentiated tumors, while liver metastases were more common in poorly differentiated tumors. Response to endocrine therapy was 35% overall, with 32% in patients with bone metastases. Response in bone was less frequent, with 18% showing radiological evidence of healing. Survival was better in responding patients. Hypercalcaemia was common, with 10% of patients dying with breast cancer developing it. Patients with hypercalcaemia had a poor prognosis, with a median survival of 3 months. Pathological fractures and spinal cord compression were also common complications. The study highlights the importance of bone metastases in breast cancer, the long clinical course, and the challenges in assessing treatment response. New approaches to treatment and more accurate assessment methods are needed to improve management.Bone metastases are common in breast cancer, with 69% of patients dying with breast cancer having skeletal metastases. Bone is the most common site of first distant relapse, more common in receptor-positive or well-differentiated tumors. Patients with disease confined to the skeleton have a median survival of 24 months, compared to 3 months after first relapse in the liver. Hypercalcaemia occurs in 10% of patients with breast cancer, often with widespread skeletal involvement. Response to treatment in bone is less than overall response, with many patients having static disease. Palliation of symptoms, control of disease, and evaluation of therapy are important. Bone metastases may be asymptomatic but can cause pain, hypercalcaemia, pathological fractures, and leuco-erythroblastic anaemia. Patients with bone metastases often have a long clinical course, with remissions and requiring palliative therapy. Assessing response to systemic therapy in bone is difficult, as UICC criteria require radiological evidence of healing, which may not be apparent for 4–6 months. The study analyzed 587 patients who died between 1979–1984 and 2240 patients with primary breast cancer. Bone was the most common site of first distant relapse, with 47% of all first distant relapses occurring in bone. Patients with first relapse in bone had a median survival of 20 months, compared to 3 months after first relapse in the liver. Tumor characteristics, such as hormone receptor status and histological grade, were compared between patients with first relapse in bone and liver. Bone metastases were more common in well-differentiated tumors, while liver metastases were more common in poorly differentiated tumors. Response to endocrine therapy was 35% overall, with 32% in patients with bone metastases. Response in bone was less frequent, with 18% showing radiological evidence of healing. Survival was better in responding patients. Hypercalcaemia was common, with 10% of patients dying with breast cancer developing it. Patients with hypercalcaemia had a poor prognosis, with a median survival of 3 months. Pathological fractures and spinal cord compression were also common complications. The study highlights the importance of bone metastases in breast cancer, the long clinical course, and the challenges in assessing treatment response. New approaches to treatment and more accurate assessment methods are needed to improve management.