Brain Tumors: Primary - Diagnosis

Determining a Prognosis

The survival rates in people with brain tumors depend on many different variables.

Whether the tumor is malignant or benign
Cancer cell type and location (location affects whether the tumor can be removed surgically or not)
The tendency to spread and the growth rate (tumor grade)
Patient's age
Patient's ability to function
Duration of symptoms

The outlook is poorer in the very youngest and very oldest patients, although younger patients who survive two years after diagnosis have a much better outlook than older patients.

Grading Tumors. Malignant primary brain tumors are classified according to tumor grade. Grade I is the least malignant and Grades IV and V are the most dangerous. Grading a tumor attempts to predict its tendency to spread and its growth rate. It is based on the appearance of the tumor cells as seen under a microscope.

Lower-grade (I and II) tumor cells are well defined and almost normal-shaped. (Some primary low-grade brain tumors are curable by surgery alone, and some are curable by surgery and radiotherapy. Low-grade tumors tend to have the most favorably survival rates and high-grade the least. However, this is not always the case. For example, some low-grade II gliomas are at very high risk for progression.)
Higher-grade (III and IV) tumor cells are abnormally shaped and are more diffuse, which indicates more aggressive behavior. (High-grade brain tumors usually require surgery, radiotherapy, chemotherapy, and possibly investigational treatments.)
In tumors that contain a mixture of different-grade cells, the tumor is graded using the highest-grade cells in the mixture, even when there are very few of them.

Biologic Markers. Elevated levels of certain cancer-associated molecules or compounds may be correlated with prognosis. For example, evidence of genetically mutated p53 indicates a poorer prognosis in younger patients with glioblastoma multiforme.

Elevations of epidermal growth factors (EGF) or vascular endothelial growth factors (VEGF) suggest aggressive tumors. High levels of the receptor for EGF (EGFR), in fact, are found in 70% of glioblastoma specimens.

Genetic Profiles of Cancer Cells. Analyses that identify genetic types may soon help clinicians determine if patients with specific brain tumor cells might response to one treatment more than another. For example, specific genetic profiles of oligodendrogliomas have been associated with predictable responses to certain agents called nitrosourea alkylating agents (especially carmustine).