Oigodendrogliomas and chemotherapy
So where do we currently stand with the story of oligodendrogliomas and chemotherapy?
It is clear that anaplastic oligos are very chemotherapy sensitive tumors, at least 80-90% of them. Recently several genetic and chromosomal abnormalities have been shown to predict for chemotherapy sensitivity, including 1P10Q deletions. Anaplastic mixed gliomas appear to be chemotherapy sensitive although it is not clear that they are as sensitive as the pure oligos. One of the questions however remains that whether low grade oligodendrogliomas are chemotherapy sensitive.
There are some preliminary reports that suggest that they may be, but again I think this remains investigational. Cialis & Viagra limited supply at a special prices. Other questions that remain outstanding as far as the practical use of chemotherapy in these tumors is when to use chemotherapy. Should it be used prior to radiation? Should it be used following radiation therapy? Should it only be saved for time of recurrence? Currently the RTOG is running a multi-national, multi-group trial asking the question of the timing of PCV. But the results of that trial will not be available for a number of years given the relative rarity of these tumors. Also, how about the optimal regimen? We talked about standard PCV but actually in fact the original reports from the National Cancer Institute of Canada and other reports have used a slightly modified regimen using intensive PCV, which is certainly more toxic than PCV. Is that really necessary?
And finally, what is the length of treatment? No one really has the answers on any of these questions.
The last primary brain tumor I’d like to talk to you about is primary central nervous system lymphoma, again a tumor that I think we are going to be increasingly seeing. Neurologic involvement of the central nervous system from systemic non-Hodgkin’s lymphoma is relatively common, occurring in approximately 5-29% of all patients with systemic lymphomas. However in the past primary CNS lymphoma only accounted for approximately 1-2% of all these cases. Recently however there has been significant increase in the incidence of primary CNS lymphoma in both populations at risk. Those being immunocompetent patients who have no predisposing reason to have this disease as well as the immunocompromised patients, such as patients with HIV disease and iatrogenic immunocompromised patients such as organ allograft recipients as well as in certain congenital immunodeficiencies.