SANS Radiosurgery Flashcards
Seorang laki-laki 37 thn dengan kejang tonik-klonik
dan ditemukan memiliki unruptured AVM 2 cm di korteks sensorimotor. Angiografi menunjukkan tidak ada aneurisma dan adanya drainase vena superficial dan deep. Pasien memilih radiosurgery untuk penyakitnya, Spetzler-Martin Grade III AVM. Volume 3,6 cc AVM ditangani dengan 20 Gy hingga 50% garis isodose
A. Radiasi yang diinduksi defisit
B. Perdarahan yang diinduksi defisit
C. Obliterasi AVM total
D. Obliterasi AVM subtotal
C. Obliterasi AVM total
The most likely outcome is complete obliteration with no new deficits. The main factor that predicts AVM obliteration after radiosurgery is radiation dose. The chance of obliteration is approximately 90 percent, 80 percent, and 70 percent for AVM margin doses of 20 Gy, 18 Gy, and 16 Gy, respectively. The chance of radiation related complications is related to the AVM location, AVM volume, and radiation dose. For larger AVM volumes, the radiation dose is typically decreased to keep the chance of radiation related complications less than five percent. The primary disadvantage of AVM radiosurgery compared to surgical resection is that patients continue to have a hemorrhage risk until the AVM is completely obliterated. The latency interval after radiosurgery until AVM obliteration is typically between one and four years. Although deficit related to hemorrhage is possible in this case, it is less likely in a patient who presented with seizures and does not harbor perinidal aneurysms.
Seorang wanita 46 tahun dengan penyakit berulang Cushing setelah reseksi trans-sphenoidal telah terbukti dgn MR perluasan tumor ke sinus kavernosus. Dia memilih terapi radiosurgery. Apakah komplikasi tersering setelah radiosurgery pituitary adenoma?
A. Diabetes Insipidus B. Diplopia C. Insufisiensi anterior pituitary D. Visual loss E. Oklusi arteri karotis
The most likely complication after pituitary adenoma radiosurgery is anterior pituitary insufficiency. The incidence of new anterior pituitary deficits ranges from 10 percent for small tumors to as much as 50 percent for large tumors that fill the entire sella. Higher radiation doses also cause a greater incidence of new endocrine deficits. Diabetes insipidus after radiosurgery is exceedingly rare. Visual loss after pituitary adenoma radiosurgery is less than two percent if the maximum dose to the optic apparatus is below 10-12 Gy. The risk of diplopia due to injury of cranial nerves 3, 4, and 6 is approximately one percent total. Carotid artery occlusion has been reported after radiosurgery for sellar and para-sellar tumors, but in the typical dose range utilized (tumor margin doses of 12-25 Gy), the incidence is less than one percent.
Wanita 48 tahun dengan neuralgia trigeminal refraktori medis memilih terapi radiosurgical. Manakah dosis radiasi maksimum paling tepat untuk neuralgia trigeminal radiosurgery?
A. 20 Gy B. 40 Gy C. 60 Gy D. 80 Gy E. 100 Gy
D. 80 Gy
The most appropriate maximum dose for trigeminal neuralgia radiosurgery is 80 Gy. Although some of the first radiosurgical procedures were for trigeminal neuralgia, the inability to clearly image the trigeminal system limited the usefulness of this technique. However, with the advent of MRI, physicians are able to visualize the trigeminal root for radiosurgery dose planning. A prospective, multi-institutional dose escalation trial showed that patients receiving a maximum radiation dose of 70 Gy or more had a significantly greater chance of complete pain relief compared to patients receiving less than 70 Gy. Later studies showed that the chance of bothersome facial numbness was significantly higher for patients treated at doses above 90 Gy. Consequently, most radiosurgical centers limit the dose for trigeminal neuralgia radiosurgery to 80 Gy in the hope of achieving better facial pain outcomes than reported with 70 Gy with an acceptable incidence of new facial sensory loss. Other factors that have been associated with improved facial pain outcomes are normal pre-operative facial sensation, increased dose to the brainstem, and absence of prior surgery. Negative predictors for pain relief after radiosurgery has included patients with trigeminal neuralgia related to multiple sclerosis or patients with a constant pain component.
Laki-laki 56 tahun dengan riwayat karsinoma sel renal datang dengan nyeri punggung terlokalisir tetapi tanpa mielopathi. Radiografi menunjukkan normal alignment dan tidak ada bukti ketidakstabilan. MRI menunjukkan dorsal, enhancing paraspinal mass dengan ekstensi ke spinal canal. Manakah hasil paling mendekati dari radiosurgery stereotactic pada pasien metastasis spine?
A. Stabilisasi tumor tetapi nyeri punggung persisten
B. Stabilisasi tumor dengan membaiknya gejala nyeri punggung
C. Stabilisasi tumor dengan new onset myelopathy
D. Perkembangan tumor menyebabkan kompresi spinal cord
E. Perkembangan tumor menyebabkan kolaps vertebral
B. Stabilisasi tumor dengan membaiknya gejala nyeri punggung
The most likely outcome after stereotactic radiosurgery of this spine metastasis is tumor stabilization with an improvement in back pain. Utilizing the general concepts developed over 30 years of intracranial radiosurgery, it has become possible to perform high-dose, single fraction (radiosurgery) radiation delivery to spinal and para-spinal lesions. Although the follow-up available after spine radiosurgery is limited, spine radiosurgery has been shown to be feasible, safe, and effective. Tumor control is achieved in the majority of patients, and improvement in axial and radicular symptoms has been noted in more than 90 percent of affected patients. Contraindications to spine radiosurgery include mechanical instability. The chance of radiation-induced myelopathy or vertebral necrosis after spine radiosurgery is very low.
Laki-laki 59 tahun datang dengan SNHL high frequency, diskriminasi bicara mendekati normal (90% pada 40 dB) dan MRI menunjukkan 10 mm massa uniform yang meluas hingga internal auditory canal. Manakah komplikasi paling tepat dari stereotactic surgery pada lesi ini ?
A. Diplopia B. Baal pada wajah C. Hilang pendengaran D. Kelemahan pada wajah E. Kesulitan menelan
C. Hilang pendengaran
The most likely complication after vestibular schwannoma radiosurgery is hearing loss. As a less invasive alternative to surgical resection, stereotactic radiosurgery has been utilized increasingly over the past 20 years for patients with vestibular schwannomas. Preservation of useful hearing (speech discrimination scores greater than 50% and a pure tone average less than 50 dB) is possible in approximately 60 percent of patients after radiosurgery. Facial weakness or numbness occurs in less thanfour percent of patients. Diplopia or swallowing difficulty is rare. In large radiosurgical series, the need for later tumor resection has been less than five percent.
Laki-laki 63 thn dengan riwayat kanker paru2 non small cell datang dengan keluhan sakit kepala. MRI otak menunjukkan dua peningkatan lesi @ 2cm dengan edema vasogenik ringan dan tanpa efek massa. Manakah yg didukung oleh bukti kelas 1 tentang radiosurgery stereotactic (SRS) dan terapi radiasi seluruh otak (WBRT)
A. Untuk pasien dengan metastasis 1-3 di otak, SRS saja dapat menghasilkan output kognitif awal yang lebih baik daripada SRS plus WBRT
B. Untuk pasien dengan metastasis 1-4 di otak, SRS saja memiliki angka harapan hidup (survival) lebih buruk dibanding SRS plus
C. Untuk pasien dengan metastasis 1-3 di otak, SRS plus WBRT meningkatkan lama angka harapan hidup jika dibandingkan sama
D. Untuk pasien dengan metastasis 1 di otak, SRS memiliki angka harapan hidup (survival) lebih baik dibandingkan WBRT
A. Untuk pasien dengan metastasis 1-3, SRS saja dapat menghasilkan output kognitif awal yang lebih baik daripada SRS plus WBRT
SRS alone results in better early cognitive outcomes compared to SRS + WBRT for patients with 1-3 metastases.Recent class I evidence reported by Chang et al (2009) demonstrated that early neurocognitive outcomes are significantly better in patients with one to three metastases who received SRS only, when compared to SRS plus up-front WBRT. This single institution study specifically examined cognition using the Hopkins Verbal Learning Test; differences in cognition were found between groups at 4 and 6 months. There was a high rate of salvage therapy requirement (87%) in the SRS group, including surgical resection and WBRT.
The RTOG 9508 study demonstrated that for patients with a single brain metastasis there was a modest survival advantage for patients treated with WBRT and stereotactic radiosurgery boost versus those treated with WBRT alone. The study included patients with one to three metastatic lesions and was powered to investigate the treatment effect for both the single metastasis subgroup as well as for the larger 1-3 metastases cohort. There was no survival benefit of WBRT plus SRS boost for patients with more than one lesion.
Aoyama et al (2006) demonstrated that for one to four brain metastases, there was no difference in survival between patients treated with SRS only (when combined with salvage therapy as needed) compared to SRS plus up-front WBRT. There was a higher rate of brain metastatic recurrence and salvage treatment requirement in the SRS only group. However, local control rates were the same between groups at one year.
Wanita 65 thn dengan tumor intracanalicular kiri 6 mm dan semakin memburuk secara progressif tetapi pendengaran masih baik dengan MRI. apakah manajemen terapi terbaik pasien ini?
A. Operasi pengangkatan melalui translabyrinthine
B. Stereotactic radiosurgery
C. Operasi pengangkatan melalui retrosigmoid
D. Reassurance, observasi, follow up dgn MRI dalam 1 thn
B. Stereotactic radiosurgery
Stereotactic radiosurgery affords a low rate (60%) of hearing preservation with margin doses of 12-13 Gy. Hearing preservation may be more likely in patients for whom a lower dose is delivered to the cochlea. This is usually possible when the tumor is smaller in volume.
Resection via a translabryinthine approach will not preserve the patient’s hearing. Given the patient’s age, radiosurgery is usually preferable to open surgery via a retrosigmoid approach.
Apakah titik dosis maksimum yg aman yg dapat ditoleransi spinal cord pada radiosurgery spinal sesi tunggal?
A. 16 Gy
B. 14 Gy
C. 10 Gy
D. 20 Gy
C. 10 Gy
The spinal cord radiation exposure should be 10 Gy or less to a point dose of the spinal cord when radiation is delivered in a single session. This dose point minimizes the risk of radiation necrosis and radiation induced myelopathy. The other doses could be toxic to the spinal cord. The typical dose for stereotactic radiosurgery for spinal metastases ranges from 14-24 Gy.
Manakah saraf kranial yg paling rentan terhadap cedera radiasi setelah radiosugery lesi sinus kavernosus?
A. Trochlear B. Abducens C. Occulomotor D. Trigeminal E. Optic
E. Optic
The cranial nerve most susceptible to radiation injury after radiosurgery of a cavernous sinus lesion is the optic nerve. Although it appears that cranial nerves will tolerate high doses of radiation (60-70 Gy) when it is delivered in multiple fractions, cranial nerves are more susceptible to injury after radiosurgery. Moreover, different types of cranial nerves appear to have distinct tolerances for radiation. The special somatic sensory nerves (optic, vestibulo-cochlear) are the most susceptible to injury after high-dose, single-fraction radiation (radiosurgery). Recent studies have shown that the chance of visual loss is less than two percent when the optic nerves and chiasm receive doses less than 12 Gy. General somatic nerves (oculomotor, trochlear, abducens, hypoglossal) are rarely affected by similar doses. The afferent component of the trigeminal nerve (general somatic afferent) is intermediate in radiation sensitivity. The length of cranial nerve that is irradiated and a prior history of radiation exposure are also important factors related to cranial nerve injury after radiosurgery.
