The incidence of breast cancer is increasing in most developed countries, but mortality has decreased in the USA, Canada and the UK during the last 10 years. Survival in Estonia is lower than in the Nordic countries (66% vs 80-86%). Skeleton is the most common site for metastases from breast cancer (in 70-90% of cases) and it occupies the first place for having metastases in 30-40% of cases. Metastatic cells due to release of substances that activate osteoclasts causing local osteolysis will damage normal bone environment. A number of clinical studies have suggested that the bisphosphonates in general, and clodronate in particular, are of benefit to patients with advanced breast cancer as they reduce osteolysis and skeletal-related events and decrease the burden of tumour. The largest reported randomized controlled study by Powles et al. on the use of bisphosphonates in patients with primary breast cancer provides three essential findings: 1) patients have less bone metastases during the treatment period with clodronate; 2) there is no significant effect on non-osseus metastases; 3) there is noted improvement in overall survival in patients treated with clodronate.