Sites of primary malignancies in patients presenting with cerebral metastases. A review of 120 cases.

A retrospective study is reported of 120 consecutive cases of patients presenting with brain metastases as the primary sign of their malignancy. Primary site was found in 62 patients (53 while alive and 9 at postmortem examination) and remained unknown in 58. Lung was the most frequent primary site (45% of known sites), and digestive malignancies were surprisingly the second most frequent primary site (19% of known sites), whereas breast was found in less than 5%. When primary site was disclosed, in 85% it was after history, clinical exam, chest x-ray, and pathologic findings. Survival was almost identical in both known and unknown primary sites: 54% versus 44% at 6 months, 20% versus 16% at 1 year, and 6% versus 5% at 2 years. It was concluded that extensive evaluations to identify primary sites do not appear to be rational in patients presenting with brain metastases.