Many trials, such as this one, are specifically for "supratentorial" tumors (that is, mainly tumors located in the cerebral lobes) and exclude "infratentorial" tumors (located in the cerebellum or brainstem). I know it doesn't seem fair to people with infratentorial tumors, and I'm not exactly sure what the reasoning is in this particular case. In some cases it might simply be an issue of tumor accessibility.
I think it is because inflammation and edema occurs at the site of poliovirus injection, which can in some cases even be fatal if that particular brain region is "important"
I contacted one of the researchers on poliovirus trial for low grade gliomas some time ago. Back then the inclusion criteria was (if I remember correctly) also that tumor had to be at least 2cm away from ventricles. I asked what the reason behind this was and got this answer:
"I believe that the surgeons feel that the insula is too deep in the brain to place the catheter. Also, the insula helps controls consciousness. Therefore, if we infuse a drug that can cause swelling in that area, this could keep that area from functioning. If that means loss of consciousness, then that is obviously not safe."
I didn't see the 2 centimeter criteria in this trial, so maybe they already found a way to control the edema to some extent, but not yet confident enough to enroll tumors in cerebellum (if this is the case).
ok, I see! Thanks, guys!I had no idea they were injecting it via catheter. Dr.Friedman has just replied to me saying they would need to see it on the case-by-case basis - I guess to estimate how far it could be from the brain stem. makes sense, I guess.
great news! do you know why the exclude cerebellum tumor locations from the trial?
ReplyDeleteMany trials, such as this one, are specifically for "supratentorial" tumors (that is, mainly tumors located in the cerebral lobes) and exclude "infratentorial" tumors (located in the cerebellum or brainstem). I know it doesn't seem fair to people with infratentorial tumors, and I'm not exactly sure what the reasoning is in this particular case. In some cases it might simply be an issue of tumor accessibility.
DeleteI think it is because inflammation and edema occurs at the site of poliovirus injection, which can in some cases even be fatal if that particular brain region is "important"
DeleteI contacted one of the researchers on poliovirus trial for low grade gliomas some time ago. Back then the inclusion criteria was (if I remember correctly) also that tumor had to be at least 2cm away from ventricles. I asked what the reason behind this was and got this answer:
Delete"I believe that the surgeons feel that the insula is too deep in the brain to place the catheter. Also, the insula helps controls consciousness. Therefore, if we infuse a drug that can cause swelling in that area, this could keep that area from functioning. If that means loss of consciousness, then that is obviously not safe."
I didn't see the 2 centimeter criteria in this trial, so maybe they already found a way to control the edema to some extent, but not yet confident enough to enroll tumors in cerebellum (if this is the case).
ok, I see! Thanks, guys!I had no idea they were injecting it via catheter. Dr.Friedman has just replied to me saying they would need to see it on the case-by-case basis - I guess to estimate how far it could be from the brain stem. makes sense, I guess.
DeleteI think this is awesome news and am very hopeful that the pediatric Polio Virus trial matches the success to date of the adult trial.
ReplyDelete