Neuro-oncology encompasses both primary brain tumors as well as secondary tumors. In other words, tumors from systemic cancers that involve the central nervous system. It’s really much too large an area to cover in one hour, so what I thought I would do is spend the majority of time talking to you about primary brain tumors, because I think most medical oncologists are least familiar with these tumors. Yet, increasingly so, medical oncologists are going to be seeing these tumors.
When one actually looks at SIR data from the NCI one can see a bi-modal distribution in the incidence of primary brain tumors. It can peak for the first few years of life, which then falls off and then begins to rise in late adolescence, peaking around the age of 60. In fact, these tumors represent very significant problems. They are the second leading cause of cancer mortality in patients under the age of 34, and the fourth leading cause of death in patients between the ages of 34 and 54. And in fact, primary brain tumors – now that leukemia has been cured in 70-80% of children – has really become the primary oncologic problem in the pediatric population. Plus, primary brain tumors do in fact present a significant cancer problem in the United States.
Depending on the classification, there are as many as 15-30 different primary brain tumors. Meningiomas are very common but they are generally restricted to surgical management and radiation and only occasionally – for rare syndromes where we see malignant meningiomas – do medical oncologists see these patients.
When we talk about brain tumors almost regardless of the type of histology, we can group the syndromes, as far as how patients present, into the following signs and symptoms. The common presenting symptom is one of headaches. Seizures are seen in approximately half the patients, as are mental status changes and some kind of motor deficits. With the more readily available access to CAT scans and MRI scans, we are picking up patients earlier in the course of their disease, and that the number of patients who are actually presenting with significant increased intracranial pressure has significantly decreased.