THE IMPLEMENTATION OF ABLATIVE HYPOFRACTIONATED RADIOTHERAPY FOR STEREOTACTIC TREATMENTS IN THE BRAIN AND BODY: OBSERVATIONS ON EFFICACY AND TOXICITY IN CLINICAL PRACTICE Lucien A. Nedzi, MD Semin Radiat Oncol 18: R2 백승숙

BACK GROUND Stereotactic treatment with radiation in the brain : 50 years old and has substantial clinical experience In the last decade, the control of radiation delivery and visualization : facilitated much wider application of these strategies to extracranial sites This review evaluates the efficacy and safety of such : ablative radiation courses using dose per fraction schedules of 10 Gy or above

ARTICLE OUTLINE Functional Radiosurgery Trigeminal Neuralgia/ Movement Disorders/ Epilepsy Arteriovenous Malformations (AVMs) Brain AVMs/ Spinal AVMs Benign Tumors Acoustic Neuromas/ Meningiomas/ Pituitary Adenomas Malignant Tumors Early-Stage Lung Cancer Brain Meta./ Liver Meta./ Spine Meta. Conclusions

RADIOSURGERY In the 1950s, neurosurgeon Lars Leksell : sufficient stereotactically localized collimated radiation from multiple different directions in single-treatment radiosurgery could create focal destruction of brain tissue Since Leksell reported the first radiosurgical thalamotomy for intractable pain in 1968, : more modern clinical experience supports efficacy in selected patients with these indications

TRIGEMINAL NEURALGIA

MOVEMENT DISORDERS Radiofrequency ventrolateral thalamotomy Radiosurgical thalamotomy The nucleus ventralis intermedius (VIM) : receives max. doses of 140 Gy with a 4-mm collimator Good Samaritan Hospital : 88% of 102 patients with Parkinson's tremor 92% of 52 patients with essential tremor  became nearly or tremor free after a 120- to 160-Gy maximum dose to the VIM Hidaka Hospital in Japan : 80% to 85% had reduced tremor and rigidity after a 130- Gy maximum dose to the VIM No radiation-induced complications were observed

EPILEPSY Barcia et al in Buenos Aires reported 11 patients treated with radiosurgery doses between 10 and 20 Gy on a linear accelerator : 82% were either off medication or had substantial reduction in seizure frequency at a mean follow-up of 8 years In a multi-institutional prospective phase II European trial 21 patients with mesiotemporal lobe epilepsy received 24-Gy radiosurgery : median number of seizures : 6.1  0.3 per month : 65% of patients were seizure free : 46% of patients developed a quadrantanopia, and 1 patient developed hemianopia on follow-up visual field testing

ARTERIOVENOUS MALFORMATIONS(AVMS)

ACOUSTIC NEUROMAS

MENINGIOMAS

PITUITARY ADENOMAS

MALIGNANT TUMORS In 1995, Blomgren et al. Report of delivering highly conformal, stereotactically localized high-dose radiation in a few fractions (stereotactic body radiation therapy) to 31 patients with malignant tumors outside the brain In the decade since this landmark report, prospective clinical trials of SBRT have been published

EARLY-STAGE LUNG CANCER

BRAIN METASTASES

LIVER METASTASES

S PINE METASTASES Single-fraction stereotactic radiation dose up to 20 Gy in selected patients with limited metastatic disease in the spine : symptomatic pain relief in 66% to 86% of patients with low morbidity

CONCLUSIONS Clinical experience with ablative hypofractionated schedules have high efficacy with acceptable toxicity in selected clinical sites Support for prospective controlled clinical trials in ablative hypofractionated radiotherapy should be encouraged