Transcript
Doctor Benzil, who is our neurosurgery from the neurosurgery department and co-director of our radiosurgery program along with me. She wasn't able to make it because of some health problems so I'm trying to see...as best as possible, I'll try to cover her presentation. And this is the theme of...let me go back...our radiosurgery team, which consisted of Dr. Benzil, myself, two other radiation oncologists, radiation physics team with Ronald Rocchio and Lynn Shih, and our radiation therapist.
Optic Nerve Sheath Meningiomas, what I will do is I'll present initially a brief introduction because they're very rare tumors. Current treatment modalities and their limitations to make a case for stereotactic radiotherapy. Risks from surgical intervention, conventional radiation methods, and single-dose radiosurgery techniques. And then the SRT Advantage and rationale for SRT in Optic Nerve Sheath Meningiomas. And then our New York Medical College study followed by conclusions.
Historically, in 1936, the first case was described in full. And first successful dissection was done in 1938. And it constitutes 1% to 2% of all meningiomas and 1.7% of all orbital tumors, and the second most common tumor of optic nerve after optic gliomas. They're mostly unilateral, only 5% bilateral cases. And median age being 40 years, and female preponderance in two-thirds of the cases. They generally present with progressive painful loss of vision, 96% cases. And optic nerve atrophy, optociliary shunt vessels, quite often if untreated can progress to blindness. And diagnosis is usually clinical and radiographic findings.
Neuroimaging findings are very important. And diffuse fusiform or tubular enlargement of the optic nerve can be seen on the CAT scan. And doughnut shape appearance, I'll show you some CT images and MRI images later. Doughnut appearance on the coronals because a tumor surrounds the optic nerve causing a concentric thickening of the optic nerve. Sometimes you might also see calcifications. And on gadolinium-enhanced and fat-suppression MRI, we can also detect and de-mark it very clearly, Optic Nerve Sheath Meningioma. And sometimes you can see a tram track appearance as well.
As you can see, these are 3 out of 10 patients that I'm going to present to show you the radiographic findings. This is a doughnut sign and a gadolinium-enhanced and fat-suppressed MRI. And sick...another patient who had extension of the tumor to the cavernous sinus. And this is a tram track appearance.
Standard treatments of like surgery, majority of the times, they can cause visual loss, significant. And conventional radiation treatments in optic meningiomas have improved vision in 75% of the cases. However, the risk is to visual apparatus and the adjacent tissues [inaudible 00:03:47]. I'll show you in next couple of slides.
Stereotactic radiosurgery risk is quite high. If the doses are more than 8 Gray and if you don't go more than 8 Gray, then your tumor control is a lot less. And usually, optic nerve is very, very known to be susceptible for single, large dose, the height is zero.
And the organs at risk, not only in Optic Nerve Sheath Meningiomas but also in parasellar radiation, the structures that are at risk are the lens, visual apparatus, optic nerves, optic chiasm, temporal lobe, and pituitary gland, usually, it's a little bit farther, cranial neuropathies.
Risk to optic apparatus, nerves, and chiasm tolerate 800 centigray in a single dose can cause problems. More than 5,400 centigray fractionated @ 180 centrigray can cause problems. Very rarely you can see in optic radiation neuritis. If you keep your dose per fraction 180 and at a total dose below 5,400 centigray, almost no reported cases in the literature. If you go beyond 200 centigray per fraction, even at 5,400, you can see complications. Lens, of course, 1,500 centigray, 57% at 8 years can...complications.
And the stereotactic radiotherapy advantage, because of the stereotactic radiotherapy, it combines the advantage of technical advantage of the SRS accuracy so you don't have to create very high volumes. And also combined with the biological advantage of fractionated radiation for normal tissue again, as long as it keep the dose per fraction 280 centigray.
And some of the previous studies for the SRT, 30 patients from this series for 50.4 centigray, 10 patients improved, 12 patients stable. So all 22 out of 30 patients had their control with 4% complications. Our earliest study with 5 patients reported, we went up to 5,400 centigray and we had 4 out of 5 controlled and 1 stable, no complications. And also the third series with 15 patients, again, keeping the dose per fraction, 180 centigray, 45 to 54, that'll certainly, will keep your complications much less.
And our current study that we have 10 patients. Actually, our first patient was treated in 1998 and he still has the vision that was improved. But later on, we haven't treated patients until we got Novalis unit so there is a significant gap between the first patient and the second patient.
And male/female ratio, 4 to 6, age, 40, youngest, and 73 oldest, all of them are unilateral but one lesion extended to chiasm that I already showed you one of the CT scan images. Progressive visual loss in all the patients. Visual acuity change in 90% of the cases.
Change in color vision and visual field loss in 80% of the patients. And the diagnostic study, CT scan was done in all, and gadolinium-enhanced and fat-suppressed MRI scan was done in all the cases. And visual field testing was done on all the cases. And follow-up consisted of 1 week, 3 months, 6 months, 12 months, and then onwards, yearly.
The treatment planning was with Frameless, Aquaplast Facial Mask Fixation, 1 millimeter CT slices and MRI images fused for simulation purposes, and treatment planning with Brainlab in 9 out of 10 and Radionics, 1 out of 10, the earliest case. Dosimetry, 3D distribution, DVH for all the cases. And Novalis-shaped beam delivery. Prescription to 90% low [inaudible 00:08:02], 180 centigray per fraction. One patient received 4,500 centigray, majority of the patients received 5,400 centigray. And these are given five fractions per week on a daily basis.
Dose distribution, this is self-explanatory. And as you can see here, the dose is completely contained and we just give a two-millimeter margin because unlike malignant lesions, you don't have to give excess of margins. If you can cut down the length of the nerve that you treat with radiation, certainly you can increase the tolerance and decrease the complications.
Results, progression of disease or visual loss in none of the cases. Significant improvement with useful vision in 80% of the cases. Stable disease or visual function, 2 out of 10 cases. All patients had either stable disease or improvement in the function. Complications, I hate to say, but we didn't have any complications. The follow-up being all these patients were followed by our neurosurgeon, Dr. Benzil, and neuro-ophthalmologist, Dr. Scott Forman. And minimum follow-up was 14 months and more than 6 years follow-up.
Visual field testing in one of the patients have...which illustrates a 50-year female with left Optic Nerve Sheath Meningioma. Pre-SRT, visual field loss as you can see. And then post-SRT, 54 Gray, dramatic improvement.
In conclusion, Fractionated Stereotactic Radiotherapy, it appears to be an effective treatment for Optic Nerve Sheath Meningiomas. And SRT in the dose ranges in this study, which is up to 5,400 centigray, 880 centigray per fraction, 5 fractions per week on a daily basis seem to be very tolerated. Thank you.
Optic Nerve Sheath Meningiomas, what I will do is I'll present initially a brief introduction because they're very rare tumors. Current treatment modalities and their limitations to make a case for stereotactic radiotherapy. Risks from surgical intervention, conventional radiation methods, and single-dose radiosurgery techniques. And then the SRT Advantage and rationale for SRT in Optic Nerve Sheath Meningiomas. And then our New York Medical College study followed by conclusions.
Historically, in 1936, the first case was described in full. And first successful dissection was done in 1938. And it constitutes 1% to 2% of all meningiomas and 1.7% of all orbital tumors, and the second most common tumor of optic nerve after optic gliomas. They're mostly unilateral, only 5% bilateral cases. And median age being 40 years, and female preponderance in two-thirds of the cases. They generally present with progressive painful loss of vision, 96% cases. And optic nerve atrophy, optociliary shunt vessels, quite often if untreated can progress to blindness. And diagnosis is usually clinical and radiographic findings.
Neuroimaging findings are very important. And diffuse fusiform or tubular enlargement of the optic nerve can be seen on the CAT scan. And doughnut shape appearance, I'll show you some CT images and MRI images later. Doughnut appearance on the coronals because a tumor surrounds the optic nerve causing a concentric thickening of the optic nerve. Sometimes you might also see calcifications. And on gadolinium-enhanced and fat-suppression MRI, we can also detect and de-mark it very clearly, Optic Nerve Sheath Meningioma. And sometimes you can see a tram track appearance as well.
As you can see, these are 3 out of 10 patients that I'm going to present to show you the radiographic findings. This is a doughnut sign and a gadolinium-enhanced and fat-suppressed MRI. And sick...another patient who had extension of the tumor to the cavernous sinus. And this is a tram track appearance.
Standard treatments of like surgery, majority of the times, they can cause visual loss, significant. And conventional radiation treatments in optic meningiomas have improved vision in 75% of the cases. However, the risk is to visual apparatus and the adjacent tissues [inaudible 00:03:47]. I'll show you in next couple of slides.
Stereotactic radiosurgery risk is quite high. If the doses are more than 8 Gray and if you don't go more than 8 Gray, then your tumor control is a lot less. And usually, optic nerve is very, very known to be susceptible for single, large dose, the height is zero.
And the organs at risk, not only in Optic Nerve Sheath Meningiomas but also in parasellar radiation, the structures that are at risk are the lens, visual apparatus, optic nerves, optic chiasm, temporal lobe, and pituitary gland, usually, it's a little bit farther, cranial neuropathies.
Risk to optic apparatus, nerves, and chiasm tolerate 800 centigray in a single dose can cause problems. More than 5,400 centigray fractionated @ 180 centrigray can cause problems. Very rarely you can see in optic radiation neuritis. If you keep your dose per fraction 180 and at a total dose below 5,400 centigray, almost no reported cases in the literature. If you go beyond 200 centigray per fraction, even at 5,400, you can see complications. Lens, of course, 1,500 centigray, 57% at 8 years can...complications.
And the stereotactic radiotherapy advantage, because of the stereotactic radiotherapy, it combines the advantage of technical advantage of the SRS accuracy so you don't have to create very high volumes. And also combined with the biological advantage of fractionated radiation for normal tissue again, as long as it keep the dose per fraction 280 centigray.
And some of the previous studies for the SRT, 30 patients from this series for 50.4 centigray, 10 patients improved, 12 patients stable. So all 22 out of 30 patients had their control with 4% complications. Our earliest study with 5 patients reported, we went up to 5,400 centigray and we had 4 out of 5 controlled and 1 stable, no complications. And also the third series with 15 patients, again, keeping the dose per fraction, 180 centigray, 45 to 54, that'll certainly, will keep your complications much less.
And our current study that we have 10 patients. Actually, our first patient was treated in 1998 and he still has the vision that was improved. But later on, we haven't treated patients until we got Novalis unit so there is a significant gap between the first patient and the second patient.
And male/female ratio, 4 to 6, age, 40, youngest, and 73 oldest, all of them are unilateral but one lesion extended to chiasm that I already showed you one of the CT scan images. Progressive visual loss in all the patients. Visual acuity change in 90% of the cases.
Change in color vision and visual field loss in 80% of the patients. And the diagnostic study, CT scan was done in all, and gadolinium-enhanced and fat-suppressed MRI scan was done in all the cases. And visual field testing was done on all the cases. And follow-up consisted of 1 week, 3 months, 6 months, 12 months, and then onwards, yearly.
The treatment planning was with Frameless, Aquaplast Facial Mask Fixation, 1 millimeter CT slices and MRI images fused for simulation purposes, and treatment planning with Brainlab in 9 out of 10 and Radionics, 1 out of 10, the earliest case. Dosimetry, 3D distribution, DVH for all the cases. And Novalis-shaped beam delivery. Prescription to 90% low [inaudible 00:08:02], 180 centigray per fraction. One patient received 4,500 centigray, majority of the patients received 5,400 centigray. And these are given five fractions per week on a daily basis.
Dose distribution, this is self-explanatory. And as you can see here, the dose is completely contained and we just give a two-millimeter margin because unlike malignant lesions, you don't have to give excess of margins. If you can cut down the length of the nerve that you treat with radiation, certainly you can increase the tolerance and decrease the complications.
Results, progression of disease or visual loss in none of the cases. Significant improvement with useful vision in 80% of the cases. Stable disease or visual function, 2 out of 10 cases. All patients had either stable disease or improvement in the function. Complications, I hate to say, but we didn't have any complications. The follow-up being all these patients were followed by our neurosurgeon, Dr. Benzil, and neuro-ophthalmologist, Dr. Scott Forman. And minimum follow-up was 14 months and more than 6 years follow-up.
Visual field testing in one of the patients have...which illustrates a 50-year female with left Optic Nerve Sheath Meningioma. Pre-SRT, visual field loss as you can see. And then post-SRT, 54 Gray, dramatic improvement.
In conclusion, Fractionated Stereotactic Radiotherapy, it appears to be an effective treatment for Optic Nerve Sheath Meningiomas. And SRT in the dose ranges in this study, which is up to 5,400 centigray, 880 centigray per fraction, 5 fractions per week on a daily basis seem to be very tolerated. Thank you.