Background: Brain metastases (BM) constitute the most common intracranial tumours and are associated with considerable morbidity and mortality. Population-based studies of the epidemiology and time trends of BM are scarce.
Methods: A population-based cohort of patients admitted to hospital with BM in Sweden between 1987 and 2006 (n=15,517) was identified and linked to nationwide registers of cancer incidence and death. Primary cancer types were assessed and time to hospitalisation and death was computed.
Results: The annual age-adjusted incidence rate of hospitalisation for BM doubled from 7 to 14 patients per 100,000 between 1987 and 2006. The most common primary tumours among women were lung (33%), breast (33%) and colorectal cancer (7%), and among men lung cancer (44%), malignant melanoma (12%) and colorectal cancer (9%). The increase was most evident for BM patients with lung cancer (both sexes) and breast cancer (women). Survival was short, with a median of 2.7 months. It varied little by cancer type and did not improve over calendar time.
Conclusion: The number of patients admitted with BM has increased rapidly in Sweden. In spite of recent improvements in the prognosis of common primary cancer types, any parallel improvement among patients with advanced cancer and BM is not indicated.