XXXX : incidence and biological behavior in a defined population.

@entity1 @entity6910 @entity66 @entity1313 @entity5 @entity39 @entity730 @entity1410 @entity204 @entity1779 @entity3271
The cases of 208 @entity1 with histologically confirmed @entity3271 were studied. The incidence represents 4.2% of all primary @entity1313 diagnosed in the Norwegian population over a 25-year period. All of these @entity5 were cerebral and the majority affected the frontal lobe. The @entity1 ' median age at diagnosis was 47 years, with a range from 3 to 76 years; 6% of the @entity3271 occurred in @entity1 . The median duration of symptoms before diagnosis was 20.5 months (mean 43 months). Plain skull x-ray films showed calcified deposits in 28% of the @entity5 . At operation, most of the @entity5 were poorly defined, without cyst formation, @entity1410 @entity39 , or @entity730 . The median duration of disease from onset of symptoms until @entity204 was 14 months in nine untreated cases. In surgically treated @entity3271 @entity1 the median survival time from onset of symptoms was 74 months. The median postoperative survival time was 35 months (mean 52 months). @entity5 @entity730 , as seen on plain skull x-ray films, was associated with a significantly longer survival period. The surgical findings of gross @entity39 , gross hypervascularity, and soft @entity5 consistency were all related to a @entity66 . Grossly well demarcated lesions were associated with a significantly longer postoperative survival. The length of postoperative survival correlated with the preoperative clinical status. The cumulative proportion of @entity1 surviving 5 years was 0.342. The @entity1 's age and sex did not have a statistically significant influence on survival time. The extent of surgical excision only seemed to play a role when the neurosurgeon considered that he had removed the whole lesion: these @entity1 had a median postoperative survival period 14 months longer than the other @entity3271 @entity1 . The @entity6910 blood group of the @entity3271 @entity1 was of prognostic value. In particular, @entity1 with blood group A had a distinctly poorer prognosis than @entity1 with O or B blood. The survival data from this unselected series indicate that @entity1779 have a less favorable prognosis than has generally been believed.
