====== Brain Metastases Epidemiology ======

Brain metastases (BMs) are the most common [[intracranial tumor]]s in adults. 
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In the last two decades, an enormous [[improvement]] in controlling extra-cranial disease has been achieved, positively affecting the [[overall survival]] of patients. However, this has led to an increased number of patients who live long enough to develop [[Brain Metastases]]
((Oxman L, Kanner AA, Laviv Y. [THERAPEUTIC OPTIONS FOR BRAIN OLIGOMETASTASES: COMPARISON BETWEEN SURGICAL RESECTION, STEREOTACTIC RADIOSURGERY, WHOLE BRAIN RADIATION THERAPY AND COMBINED MODULES IN RELATION TO SURVIVAL, FUNCTION AND OTHER CONSIDERATIONS]. Harefuah. 2023 Apr;162(4):243-249. Hebrew. PMID: 37120745.))
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[[Brain metastases]] are the most common [[intracranial tumor]]s in [[adult]]s, accounting for significantly more than one-half of brain tumors. In patients with systemic malignancies, brain metastases occur in 10 to 30 percent of adults and 6 to 10 percent of children
No reliable estimates are available on the incidence in cancer patients. This information is valuable for planning patient care and developing measures that may prevent or decrease the likelihood of metastatic brain disease
((Posner JB. Management of brain metastases. Rev Neurol (Paris). 1992;148(6-7):477-87. PMID: 1448668.))
((Sawaya R, Bindal RK. Metastatic brain tumors. In: Brain Tumors, Kaye AH, Laws ER (Eds), Churchill Livingstone, Edinburgh 1995. p.923.))
((Graus F, Walker RW, Allen JC. Brain metastases in children. J Pediatr. 1983 Oct;103(4):558-61. doi: 10.1016/s0022-3476(83)80583-6. PMID: 6620015.)).

Brain metastases are the most common cause of malignant brain tumours in adults. Of the nearly 1·5 million patients in the USA who received a primary diagnosis of cancer in 2007, about 70 000 of these primary diagnoses are estimated to eventually relapse in the brain
((FG Davis, TA Dolecek, BJ McCarthy, JL Villano Toward determining the lifetime occurrence of metastatic brain tumors estimated from 2007 United States cancer incidence data Neuro Oncol, 14 (2012), pp. 1171–1177))
((American Cancer Society Cancer Facts & FiguresAmerican Cancer Society, Atlanta, GA (2007))).

Between 20% and 40% of all patients with metastatic cancer will have brain metastases at autopsy 
((Sawaya R, Bindal RK, Lang FF, Abi-Said D. 2nd ed. New York: Churchill Livingstone; 2001. Metastatic brain tumors.)).

Rates of CNS involvement in metastatic cancer are believed to be increasing, possibly owing to better control of systemic disease with novel chemotherapies or improved metastases detection. 

However, controversies exist regarding demographic and clinical profile of brain metastases.

Analysis from the Kentucky and Alberta cancer registries similarly demonstrated the aggressive nature of lung cancer and its propensity for BM at initial presentation. Besides widespread organ involvement, no synchronous organ site predicted BM in lung cancer. BM is a common and important clinical outcome, and use of registry data is becoming more available
((Villano JL, Durbin EB, Normandeau C, Thakkar JP, Moirangthem V, Davis FG.
Incidence of brain metastases at initial presentation of lung cancer. Neuro
Oncol. 2014 Jun 2. pii: nou099. [Epub ahead of print] PubMed PMID: 24891450.)).