Clinical Outcome in Gamma Knife Radiosurgery for Metastatic Brain Tumors from the Primary Breast Cancer : Prognostic Factors in Local Treatment Failure and Survival

Objective

Brain metastases in primary breast cancer patients are considerable sources of morbidity and mortality. Gamma knife radiosurgery (GKRS) has gained popularity as an up-front therapy in treating such metastases over traditional radiation therapy due to better neurocognitive function preservation. The aim of this study was to clarify the prognostic factors for local tumor control and survival in radiosurgery for brain metastases from primary breast cancer.

Methods

From March 2001 to May 2011, 124 women with metastatic brain lesions originating from a primary breast cancer underwent GKRS at a tertiary medical center in Seoul, Korea. All patients had radiosurgery as a primary treatment or salvage therapy. We retrospectively reviewed their clinical outcomes and radiological responses. The end point of this study was the date of patient''s death or the last follow-up examination.

Results

In total, 106 patients (268 lesions) were available for follow-up imaging. The median follow-up time was 7.5 months. The mean treated tumor volume at the time of GKRS was 6273 mm³ (range, 4.5-27745 mm³) and the median dose delivered to the tumor margin was 22 Gy (range, 20-25 Gy). Local recurrence was assessed in 86 patients (216 lesions) and found to have occurred in 36 patients (83 lesions, 38.6%) with a median time of 6 months (range, 4-16 months). A treated tumor volume >5000 mm³ was significantly correlated with poor local tumor control through a multivariate analysis (hazard risk=7.091, p=0.01). Overall survival was 79.9%, 48.3%, and 15.3% at 6, 12, and 24 months, respectively. The median overall survival was 11 months after GKRS (range, 6 days-113 months). Multivariate analysis showed that the pre-GKRS Karnofsky performance status, leptomeningeal seeding prior to initial GKRS, and multiple metastatic lesions were significant prognostic factors for reduced overall survival (hazard risk=1.94, p=0.001, hazard risk=7.13, p<0.001, and hazard risk=1.46, p=0.046, respectively).

Conclusion

GKRS has shown to be an effective and safe treatment modality for treating brain metastases of primary breast cancer. Most metastatic brain lesions initially respond to GKRS, though, many patients have further CNS progression in subsequent periods. Patients with poor Karnofsky performance status and multiple metastatic lesions are at risk of CNS progression and poor survival, and a more frequent and strict surveillance protocol is suggested in such high-risk groups.     

The role of stereotactic radiosurgery in metastasis to the spine

Objective

The incidence and prevalence of spinal metastases are increasing, and although the role of radiation therapy in the treatment of metastatic tumors of the spine has been well established, the same cannot be said about the role of stereotactic radiosurgery. Herein, the authors present a systematic review regarding the value of spinal stereotactic radiosurgery in the management of spinal metastasis.

Methods

A systematic literature search for stereotactic radiosurgery of spinal metastases was undertaken. Grades of Recommendation, Assessment, Development, and Education (GRADE) working group criteria was used to evaluate the qualities of study datasets.

Results

Thirty-one studies met the study inclusion criteria. Twenty-three studies were of low quality, and 8 were of very low quality according to the GRADE criteria. Stereotactic radiosurgery was reported to be highly effective in reducing pain, regardless of prior treatment. The overall local control rate was approximately 90%. Additional asymptomatic lesions may be treated by stereotactic radiosurgery to avoid further irradiation of neural elements and further bone-marrow suppression. Stereotactic radiosurgery may be preferred in previously irradiated patients when considering the radiation tolerance of the spinal cord. Furthermore, residual tumors after surgery can be safely treated by stereotactic radiosurgery, which decreases the likelihood of repeat surgery and accompanying surgical morbidities. Encompassing one vertebral body above and below the involved vertebrae is unnecessary. Complications associated with stereotactic radiosurgery are generally self-limited and mild.

Conclusion

In the management of spinal metastasis, stereotactic radiosurgery appears to provide high rates of tumor control, regardless of histologic diagnosis, and can be used in previously irradiated patients. However, the quality of literature available on the subject is not sufficient.     

The Role of Radiosurgery in Patients with Brain Metastasis from Small Cell Lung Carcinoma

Objective

The purpose of this retrospective study was to evaluate the outcome of gamma knife radiosurgery (GKRS) and/or whole brain radiation therapy (WBRT) for the treatment of small cell lung carcinoma (SCLC) metastasis to the brain.

Methods

From 2000 to 2010, 50 patients underwent GKRS for metastatic brain lesions originating from SCLC. Among these patients, 11 received prophylactic cranial irradiation (PCI) before the development of metastatic lesions (PCI group), and GKRS was performed as an initial treatment for newly diagnosed lesions in 12 patients who had not received PCI (primary GKRS group). In addition, GKRS was performed as a salvage treatment for progressive lesions after WBRT in 27 patients (salvage GKRS group). The medical records and imaging data of all patients were retrospectively analyzed.

Results

The overall survival of the 50 patients was 20.8 months (range 1-53) after the diagnosis of primary tumor and 12.0 months (range 1-47) after the development of cerebral metastasis. Median survival after GKRS was 4.8 months (range 1-15) in the PCI group, 4.6 months (range 0-18) in the primary GKRS group, and 7.6 months (range 0-33) in the salvage GKRS group. Further treatment for progressive lesions after GKRS was necessary in 15 patients, after a mean interval of 3.8 months. Causes of death were systemic organ failure in 15 patients, deterioration of neurological state in 13 patients, and unknown or combined causes in 16 patients. The local control rate of the lesions treated with GKRS was 76.4% (decreased in 13 patients and stable in 16 patients at the final imaging follow-up (mean 5.60 months).

Conclusion

GKRS is an effective local treatment for brain metastasis from SCLC both as an initial treatment for newly diagnosed lesions after PCI and as a salvage treatment for recurrent or progressive lesions. However, the survival benefit is not significant because most patients die of systemic multi-organ failure with a short life expectancy.     

Clinical Analysis of Novalis Stereotactic Radiosurgery for Brain Metastases

Objective

The authors analyzed the effectiveness and therapeutic response of Novalis shaped beam radiosurgery for metastatic brain tumors, and the prognostic factors which influenced the outcome.

Methods

We performed a retrospective analysis of 106 patients who underwent 159 treatments for 640 metastatic brain lesions between January 2000 and April 2008. The pathologies of the primary tumor were mainly lung (45.3%), breast (18.2%) and GI tract (13.2%). We classified the patients using Radiation Therapy Oncology Group Recursive Partitioning Analysis (RPA) and then analyzed the survival and prognostic factors according to the Kaplan Meier method and univariate analysis.

Results

The overall median actuarial survival rate was 7.3 months from the time of first radiosurgery treatment while 1 and 2 year actuarial survival estimates were 31% and 14.4%, respectively. Median actuarial survival rates for RPA classes I, II, and III were 31.3 months, 7.5 months and 1.7 months, respectively. Patients'' life spans, higher Karnofsky performance scores and age correlated closely with RPA classes. However, sex and the number of lesions were not found to be significantly associated with length of survival.

Conclusion

This result suggests that Novalis radiosurgery can be a good treatment option for treatment of the patients with brain metastases.     

Multiple Gamma Knife Radiosurgery for Multiple Metachronous Brain Metastases Associated with Lung Cancer : Survival Time

Objective

We compared the survival time between patients with multiple gamma knife radiosurgery (GKRS) and patients with a single GKRS plus whole brain radiation therapy (WBRT), in patients with multiple metachronous brain metastases from lung cancer.

Methods

From May 2006 to July 2010, we analyzed 31 patients out of 112 patients who showed multiple metachronous brain metastases. 20 out of 31 patients underwent multiple GKRS (group A) and 11 patients underwent a single GKRS plus WBRT (group B). We compared the survival time between group A and B. Kaplan-Meier method and Cox proportional hazards were used to analyze relationship between survival and 1) the number of lesions in each patient, 2) the average volume of lesions in each patient, 3) the number of repeated GKRS, and 4) the interval of development of new lesions, respectively.

Results

Median survival time was 18 months (range 6-50 months) in group A and 6 months (range 3-18 months) in group B. Only the average volume of individual lesion (over 10 cc) was negatively related with survival time according to Kaplan-Meier method. Cox-proportional hazard ratio of each variable was 1.1559 for the number of lesions, 1.0005 for the average volume of lesions, 0.0894 for the numbers of repeated GKRS, and 0.5970 for the interval of development of new lesions.

Conclusion

This study showed extended survival time in group A compared with group B. Our result supports that multiple GKRS is of value in extending the survival time in patients with multiple metachronous brain metastases, and that the number of the lesions and the frequency of development of new lesions are not an obstacle in treating patients with GKRS.     

Gamma Knife Radiosurgery for Brainstem Metastasis

Objective

Brainstem metastases are rarely operable and generally unresponsive to conventional radiation therapy or chemotherapy. Recently, Gamma Knife Radiosurgery (GKRS) was used as feasible treatment option for brainstem metastasis. The present study evaluated our experience of brainstem metastasis which was treated with GKRS.

Methods

Between November 1992 and June 2010, 32 patients (23 men and 9 women, mean age 56.1 years, range 39-73) were treated with GKRS for brainstem metastases. There were metastatic lesions in pons in 23, the midbrain in 6, and the medulla oblongata in 3 patients, respectively. The primary tumor site was lung in 21, breast in 3, kidney in 2 and other locations in 6 patients. The mean tumor volume was 1,517 mm³ (range, 9-6,000), and the mean marginal dose was 15.9 Gy (range, 6-23). Magnetic Resonance Imaging (MRI) was obtained every 2-3 months following GKRS. Follow-up MRI was possible in 24 patients at a mean follow-up duration of 12.0 months (range, 1-45). Kaplan-Meier survival analysis was used to evaluate the prognostic factors.

Results

Follow-up MRI showed tumor disappearance in 6, tumor shrinkage in 14, no change in tumor size in 1, and tumor growth in 3 patients, which translated into a local tumor control rate of 87.5% (21 of 24 tumors). The mean progression free survival was 12.2 months (range, 2-45) after GKRS. Nine patients were alive at the completion of the study, and the overall mean survival time after GKRS was 7.7 months (range, 1-22). One patient with metastatic melanoma experienced intratumoral hemorrhage during the follow-up period. Survival was found to be associated with score of more than 70 on Karnofsky performance status and low recursive partitioning analysis class (class 1 or 2), in terms of favorable prognostic factors.

Conclusion

GKRS was found to be safe and effective for management of brainstem metastasis. The integral clinical status of patient seems to be important in determining the overall survival time.     

Radiosurgery for Recurrent Brain Metastases after Whole-Brain Radiotherapy : Factors Affecting Radiation-Induced Neurological Dysfunction

Objective

We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction.

Methods

In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was 12.4 cm³. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria.

Results

Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age (<60 years) and tumor volume affected survival rate (p=0.03, each). Acute (≤1 month) toxicity was observed in 22% of patients, subacute and chronic (>6 months) toxicity occurred in 21%, respectively. Less acute toxicity was observed with small tumors (<10 cm³, p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gy×cm³) was a significant predictor of both acute and chronic CNS toxicities.

Conclusion

Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.     

Preliminary Report of Multisession Gamma Knife Radiosurgery for Benign Perioptic Lesions: Visual Outcome in 22 Patients

Objective

Radiosurgery may be contraindicated for lesions adjacent to the optic pathways because of the substantial risk of visual complication. Multisession radiosurgery has been tried as a compromise between single session radiosurgery and fractionated radiotherapy. The purpose of this study is to evaluate the outcomes of multisession gamma knife radiosurgery (GKRS) in 22 patients with perioptic lesions of benign pathology.

Methods

In all 22 cases, the lesions were within 1 mm of the optic apparatus and were therefore not considered suitable for single session radiosurgery. Radiation was delivered in 3 to 4 fractions with a median cumulated marginal dose of 20 Gy (range, 15-20 Gy).

Results

During a mean follow-up of 29 months (range, 14-44 months), tumor control was achieved in 21 patients. Visual function improved in 7 patients, remained unchanged in 14 patients, and deteriorated in 1 patient with tumor progression. No other complication was observed.

Conclusion

This preliminary result supports the idea that multisession GKRS may be an effective and safe alternative for treatment in perioptic lesions that are unsuitable for single session radiosurgery.     

Clinical Results of Cyberknife? Radiosurgery for Spinal Metastases

Objective

Primary treatment of spinal metastasis has been external beam radiotherapy. Recent advance of technology enables radiosurgery to be extended to extracranial lesions. The purpose of this study was to determine the clinical effectiveness and safety of stereotactic radiosurgery using Cyberknife in spinal metastasis.

Methods

From June, 2002 to December, 2007, 129 patients with 167 spinal metastases were treated with Cyberknife. Most of the patients (94%) presented with pain and nine patients suffered from motor deficits. Twelve patients were asymptomatic. Fifty-three patients (32%) had previous radiation therapy. Using Cyberknife, 16-39 Gy in 1-5 fractions were delivered to spinal metastatic lesions. Radiation dose was not different regarding the tumor pathology or tumor volume.

Results

After six months follow-up, patient evaluation was possible in 108 lesions. Among them, significant pain relief was seen in 98 lesions (91%). Radiological data were obtained in 83 lesions. The mass size was decreased or stable in 75 lesions and increased in eight lesions. Radiological control failure cases were hepatocellular carcinoma (5 cases), lung cancer (1 case), breast cancer (1 case) and renal cell carcinoma (1 case). Treatment-related radiation injury was not detected.

Conclusion

Cyberknife radiosurgery is clinically effective and safe for spinal metastases. It is true even in previously irradiated patients. Compared to conventional radiation therapy, Cyberknife shows higher pain control rate and its treatment process is more convenient for patients. Thus, it can be regarded as a primary treatment modality for spinal metastases.     

Effects of an Epithelial Growth Factor Receptor-Tyrosine Kinase Inhibitor Add-on in Stereotactic Radiosurgery for Brain Metastases Originating from Non-Small-Cell Lung Cancer

Objective

This study was aimed at optimizing the treatment of non-small-cell lung cancer (NSCLC) patients who are candidates for stereotactic radiosurgery (SRS) for brain metastases and harbor activating epithelial growth factor receptor (EGFR) mutations.

Methods

We retrospectively reviewed the medical records from 2005 to 2010 of NSCLC patients with brain metastases harboring an activating EGFR mutation. Patients who received a combination therapy of SRS and EGFR-tyrosine kinase inhibitor (TKI) for brain metastases and those who received SRS without EGFR-TKI were compared. The primary endpoint was progression-free survival (PFS) of the brain metastases.

Results

Thirty-one patients were eligible for enrolment in this study (SRS with TKI, 18; SRS without TKI, 13). Twenty-two patients (71.0%) were women and the median overall age was 56.0 years. PFS of brain lesions was not significantly prolonged in SRS with TKI treatment group than in SRS without TKI group (17.0 months vs. 9.0 months, p=0.45). Local tumor control rate was 83.3% in the combination therapy group, and 61.5% in the SRS monotherapy group (p=0.23). There were no severe adverse events related with treatment in both groups.

Conclusions

Therapeutic outcome of concurrent SRS and TKI treatment was not superior to SRS monotherapy, however, there was no additive adverse events related with combined treatment.     

Efficacy and Safety of Fractionated Stereotactic Radiosurgery for Large Brain Metastases

Objective

To investigate the efficacy and safety of fractionated stereotactic radiosurgery for large brain metastases (BMs).

Methods

Between June 2011 and December 2013, a total of 38 large BMs >3.0 cm in 37 patients were treated with fractionated Cyberknife radiosurgery. These patients comprised 16 men (43.2%) and 21 women, with a median age of 60 years (range, 38-75 years). BMs originated from the lung (n=19, 51.4%), the gastrointestinal tract (n=10, 27.0%), the breast (n=5, 13.5%), and other tissues (n=3, 8.1%). The median tumor volume was 17.6 cc (range, 9.4-49.6 cc). For Cyberknife treatment, a median peripheral dose of 35 Gy (range, 30-41 Gy) was delivered in 3 to 5 fractions.

Results

With a median follow-up of 10 months (range, 1-37 months), the crude local tumor control (LTC) rate was 86.8% and the estimated LTC rates at 12 and 24 months were 87.0% and 65.2%, respectively. The median overall survival (OS) and progression-free survival (PFS) rates were 16 and 11 months, respectively. The estimated OS and PFS rates at 6, 12, and 18 months were 81.1% and 65.5%, 56.8% and 44.9%, and 40.7% and 25.7%, respectively. Patient performance status and preoperative focal neurologic deficits improved in 20 of 35 (57.1%) and 12 of 17 patients (70.6%), respectively. Radiation necrosis with a toxicity grade of 2 or 3 occurred in 6 lesions (15.8%).

Conclusion

These results suggest a promising role of fractionated stereotactic radiosurgery in treating large BMs in terms of both efficacy and safety.     

Long term outcomes of gamma knife radiosurgery for typical trigeminal neuralgia-minimum 5-year follow-up

Objective

Gamma knife radiosurgery (GKRS) is the least invasive surgical option for patients with trigeminal neuralgia (TN). However, the indications and long term outcomes of GKRS are still controversial. Additionally, a series with uniform long-term follow-up data for all patients has been lacking. In the present study, the authors analyzed long-term outcomes in a series of patients with TN who underwent a single GKRS treatment followed by a minimum follow-up of 60 months.

Methods

From 1994 to 2009, 40 consecutive patients with typical, intractable TN received GKRS. Among these, 22 patients were followed for >60 months. The mean maximum radiation dose was 77.1 Gy (65.2-83.6 Gy), and the 4 mm collimator was used to target the radiation to the root entry zone.

Results

The mean age was 61.5 years (25-84 years). The mean follow-up period was 92.2 months (60-144 months). According to the pain intensity scale in the last follow-up, 6 cases were grades I-II (pain-free with or without medication; 27.3%) and 7 cases were grade IV-V (<50% pain relief with medication or no pain relief; 31.8%). There was 1 case (facial dysesthesia) with post-operative complications (4.54%).

Conclusion

The long-term results of GKRS for TN are not as satisfactory as those of microvascular decompression and other conventional modalities, but GKRS is a safe, effective and minimally invasive technique which might be considered a first-line therapy for a limited group of patients for whom a more invasive kind of treatment is unsuitable.     

Survival of brain metastatic patients treated with gamma knife radiosurgery alone

Purpose

To evaluate the impact of gamma knife radiosurgery (GKRS) alone on the survival of brain metastasis patients.

Methods

Fifty patients, 17 men and 33 women, with 169 metastatic tumors were retrospectively reviewed. Before therapy, their mean Karnofsky Performance Score was 78. The majority of their primary cancers stemmed from the lung (56%). Thirty-five patients harbored multiple tumors. The mean tumor volume was 3.7 ml. The mean margin dose was 16 Gy. The mean/median clinical follow-up period was 37/25 weeks.

Results

The overall image-proven tumor control rate was 76%, and the median tumor progression-free period was 26 weeks after radiosurgery. The survival rate of the patients was 58% and 30% at 6 and 12 months, respectively, and the overall median post-radiosurgery survival time was 38 weeks. Both uni- and multi-variate Cox analyses demonstrated that patients with KPS ≧ 80 or who were in Recursive Partitioning Analysis Class I survived significantly longer (p < 0.05).

Conclusions

Patients treated with GKRS alone can prolong their median lifespan by a range of 6–10 months if they are in a good pre-GKRS functional state.     

Treatment Outcomes of Pediatric Craniopharyngioma : A 15-Year Retrospective Review of 35 Cases

Objective

The aim of this study was to describe a single center''s experience in the management of craniopharyngiomas in children over a 15-year period.

Methods

The clinical records of pediatric patients treated for craniopharyngiomas between December 1995 and February 2011 were reviewed. Thirty-five pediatric patients diagnosed with craniopharyngioma were treated, and their medical records and imaging data were analyzed retrospectively.

Results

The mean follow-up duration was 76 months (range, 10-195). Overall survival and local control rates at 10 years were 94.7±5.1% and 37.1±11.9%, respectively. The female-to-male ratio was 16 : 19, and the mean age was 8.6 years (range, 1-17). Initially, gross total resection (GTR) was performed in 30 patients; subtotal resection (STR) followed by radiotherapy was performed in 5 patients. Of the 14 cases that showed recurrence after GTR, 5 patients were treated with GTR, 1 with radiation therapy (RT), 4 with gamma knife radiosurgery (GKRS), and 4 with subtotal resection followed by RT. No patients who underwent RT or GKRS had recurrences. Two cases with recurrence after STR followed by RT were treated with GTR. One patient died of hormonal insufficiency 64 months after the first surgery. The overall median time progression was 51.2 months (range, 3-182) : 49.7 months in the patients who underwent GTR and 60.2 months in the patients who underwent STR followed by RT.

Conclusion

If safe resection is possible, GTR at the initial treatment should be attempted to reduce the tumor recurrence. However, if the tumor recurs after the first surgery, RT or GKRS with/without reoperation may be an effective salvage treatment for recurrent craniopharyngioma.     

The Treatment Outcome of Elderly Patients with Idiopathic Trigeminal Neuralgia : Micro-Vascular Decompression versus Gamma Knife Radiosurgery

Objective

This study was designed to compare the efficacy of micro-vascular decompression (MVD) and Gamma knife radiosurgery (GKRS) for elderly idiopathic trigeminal neuralgia patients by analyzing the clinical outcome.

Methods

In the past 10 years, 27 elderly patients were treated with MVD while 18 patients were treated with GKRS (>65-years-old). We reviewed their clinical characteristics and clinical courses after treatment as well as the treatment outcomes. For patients who were treated with MVD, additional treatment methods such as rhizotomy were combined in some areas. In GKRS, we radiated the root entry zone (REZ) with the mean maximum dose of 77.8 (70-84.3) Gy and one 4 mm collimator.

Results

The mean age was 68.1 years for MVD, and 71.1 years for GKS group. The average time interval between first presenting symptom and surgery was 84.1 (1-361) months, and 51.4 (1-120) months, respectively. The mean follow-up period after the surgery was 35.9 months for MVD, and 33.1 months for GKRS. According to Pain Intensity Scale, MVD group showed better prognosis with 17 (63%) cases in grade I-II versus 10 (55.6%) cases in GKRS group after the treatment. The pain recurrence rate during follow up did not show much difference with 3 (11.1%) in MVD, and 2 (11.1%) in GKRS. After the treatment, 2 cases of facial numbness, and 1 case each of herpes zoster, cerebrospinal fluid (CSF) leakage, hearing disturbance, and subdural hematoma occurred in MVD Group. In GKRS, there was 1 (5.6%) case of dysesthesia but was not permanent. Three cases were retreated by GKRS but the prognosis was not as good as when the surgery was used as primary treatment, with 1 case of grade I-II, and 1 case of recurrence. The maximal relieve of pain was seen just after surgery in MVD group, and 1 year after treatment in GKRS group.

Conclusion

For trigeminal neuralgia patients with advanced age, MVD showed advantages in immediately relieving the pain. However, in overall, GKRS was preferable, despite the delayed pain relief, due to the lower rate of surgical complications that arise owing to the old age.     

The role of stereotactic cyst aspiration for glial and metastatic brain tumors

OBJECTIVE: To evaluate the role of stereotactic cyst aspiration in the context of multimodality management of cystic glial and metastatic tumors, we retrospectively reviewed our experience with 38 patients during a 10-year interval. METHODS: All 38 patients had one or more computed tomography or magnetic resonance imaging guided stereotactic cyst aspirations. Twenty-seven patients had glial neoplasms and 11 had metastatic brain tumors. Twenty-two patients underwent cyst aspiration as the initial treatment modality while 15 patients had cyst aspiration following previous treatments. RESULTS: In the immediate postoperative period, 19 of the 27 (70%) patients with gliomas and nine of the 11 (82%) patients with metastatic tumors experienced symptomatic improvement. No procedure-related morbidity was encountered. Twelve patients (31.5%) eventually required a catheter-reservoir system. Thirty-seven percent of patients with cystic glial neoplasms and 18% of patients with metastatic tumors had delayed cytoreductive surgery by craniotomy subsequent to stereotactic cyst aspiration. Reduction in tumor volume following aspiration facilitated Gamma knife radiosurgery in seven patients. CONCLUSION: Single stereotactic aspiration is a low risk procedure that provides immediate relief of symptoms in patients with cystic brain tumors. It appears to be valuable together with the use of other therapeutic strategies.     

Intracavitary Radiation Therapy for Recurrent Cystic Brain Tumors with Holmium-166-Chico : A Pilot Study

Objective

Intracavitary injection of beta-emitting radiation source for control of cystic tumors has been tried with a benefit of localized internal radiation. The authors treated cystic brain tumor patients with Holmium-166-chitosan complex (Ho-166-chico), composed of a beta-emitting radionuclide Holmium-166 and biodegradable chit polymer, and evaluated the safety and effective measurement for response.

Methods

Twenty-two patients with recurrent cystic brain tumor and/or located in a deep or eloquent area were enrolled in this pilot study. The cyst volume and wall thickness were determined on CT or MRI to assess radiological response. The activity of Ho-166-chico injected via Ommaya reservoir was prescribed to be 10-25 Gy to the cyst wall in a depth of 4 mm.

Results

There was neither complications related to systemic absorption nor leakage of Ho-166-chico in all 22 patients. But, two cases of oculomotor paresis were observed in patients with recurrent craniopharyngioma. Radiological response was seen in 14 of 20 available follow-up images (70%). Seven patients of ''evident'' radiological response experienced more than 25% decrease of both cyst volume and wall thickness. Another 7 patients with ''suggestive'' response showed decrease of cyst volume without definitive change of the wall thickness or vice versa. All patients with benign tumors or low grade gliomas experienced symptomatic improvement.

Conclusion

Ho-166-chico intracavitary radiation therapy for cystic tumor is a safe method of palliation without serious complications. The determination of both minimal effective dosage and time interval of repeated injection through phase 1 trial could improve the results in the future.