Stereotactic radiosurgery for brainstem metastases.

OBJECT: Brainstem metastases portend a dismal prognosis. Surgical resection is not part of routine management and radiation therapy has offered little clinical benefit. Radiosurgery provides a safe and effective treatment for many patients with brain metastasis, but its role in the brainstem has not been evaluated. In this study the authors examine the role of radiosurgery in the treatment of brainstem metastases. METHODS: The authors reviewed the outcomes after stereotactic radiosurgery in 26 patients with 27 brainstem metastases. Tumor locations included the pons (21 tumors) and midbrain (six tumors): 14 patients had additional tumors in other locations. Twenty patients presented with brainstem signs. The median dose to the tumor margin was 16 Gy (range 12-20 Gy). Twenty-four patients received fractionated whole-brain radiation therapy (WBRT) and 12 underwent additional chemotherapy or immunotherapy. The median follow-up time in these patients was 9.5 months (range 1-43 months). After radiosurgery, the local control rate in brainstem tumors was 95%. In one patient in whom the tumor initially decreased in size, tumor enlargement was seen 7 months later. The median survival time was 11 months after diagnosis and 9 months after radiosurgery. Thirteen patients improved, 10 were stable, and three deteriorated. Eventually, 22 patients died, 18 of progression of their extracranial disease, three of new tumor growth (including one hemorrhage into a new brain metastasis), and one of extracranial disease plus new brain tumor growth. CONCLUSIONS: Although they have slightly lower than the expected survival rates of patients with nonbrainstem tumors, patients with brainstem metastases may achieve effective palliation after stereotactic radiosurgery and WBRT.     

Stereotactic radiosurgery as a salvage treatment for locally persistent and recurrent nasopharyngeal carcinoma.

BACKGROUND: The purpose of this work was to study the efficacy of stereotactic radiosurgery as a salvage treatment in patients with locally persistent and recurrent nasopharyngeal carcinoma (NPC). METHODS: Between March 1996 and August 1997, 10 patients with locally persistent or recurrent NPC were treated by linac-based stereotactic radiosurgery. Four patients had radiosurgery for persistent disease after a first course of radiotherapy, 3 had radiosurgery as a boost after reirradiation for local recurrence, and 3 had radiosurgery for disease that recurred after reirradiation. The tumor volume ranged from 1.3 to 23.7 cc (median: 5.2). Treatment was prescribed at 80% isodose line and ranged from 12 to 18 Gy (median: 13.4), with a mean tumor surface dose ranged from 10-21 Gy (median: 14). The median clinical follow-up was 10.5 months (range 8-27), and the median imaging follow-up was 9.5 months (range 6-26). RESULTS: One patient had complete regression of tumor after radiosurgery, five had reduction in tumor size, three had no change, and one had progression of tumor. The overall response rate to radiosurgery was 60% (6/10), with 10% (1/10) developing in-field progression. Excluding patients receiving radiosurgery as a boost treatment after reirradiation, the response rate was 57% (4/7) and none developed in-field progression. Only one patient developed a new cranial neuropathy in the absence of disease progression. CONCLUSION: In selected patients with locally persistent or recurrent NPC, stereotactic radiosurgery can be considered as a salvage treatment with good short-term local control. The complications appear to be minimal except for treating recurrence in the cavernous sinus. Early results are encouraging although more experience and longer follow-up are still needed to better define the role of radiosurgery in the management of persistent and recurrent NPC.     

Stereotactic radiosurgery as a salvage treatment for recurrent skull base adenoid cystic carcinoma

Twelve patients (15 lesions) with recurrent skull base adenoid cystic carcinoma (ACC) were treated by Gamma Knife stereotactic radiosurgery (SRS). The tumor volume ranged from 2 to 103 ml (median 15 ml). Treatment was prescribed at the 40-60% isodose line and ranged from 10 to 18 Gy (median: 13.0 Gy). The median follow-up period was 18 months (range 3-55). Six patients were alive and 6 dead at the end of the follow-up period. Only 1 patient died from local tumor recurrence. Ten among 15 tumors treated by SRS decreased in size until the end of the follow-up period or the patients' death. Three remained unchanged in size. Two tumors initially regressed but then increased in size. In selected patients with recurrent skull base ACC, SRS can be considered as a salvage treatment with good local control.     

Linac radiosurgery for brain metastasis of melanoma

PURPOSE: To evaluate the efficacy and toxicity of stereotactic radiotherapy in the treatment of brain metastases of melanoma. PATIENTS AND METHODS: From 1994 to 2001, 25 patients presenting with 61 metastases of cutaneous melanoma were treated with radiosurgery. Median age was 47 years (range: 25-73 years) and median Karnofski performance status 80 (range: 50-100). Twenty patients had one radiosurgery, 5 had two or three. Median metastasis diameter was 21 mm (range: 6-54.4 mm), and median metastasis volume was 1.7 cm(3) (range: 0.4-25.6 cm(3)). Irradiation was delivered by a linear accelerator. Median minimal dose was 14.1 Gy (range: 10-19.4 Gy), and median maximal dose was 20.5 Gy (range: 16-48 Gy). RESULTS: Mean follow-up was 12.6 months (range: 1-85 months). Five metastases progressed (9.8%), 2-12 months after radiosurgery. Three-, 6- and 12-month local control rates were 95 +/- 3, 90 +/- 5 and 84 +/- 7%, respectively. By univariate analysis, only absence of extracranial tumor was a prognostic factor of local control. Three-, 6- and 12-month brain-disease-free survival rates were 75 +/- 9, 68 +/- 11 and 38 +/- 13%, respectively. According to univariate analysis, only the Score Index for Radiosurgery in brain metastases (SIR) was a prognostic factor of brain-event-free survival (p = 0.03). Median survival was 8 months. Three-, 6- and 12-month overall survival rates were 75 +/- 9, 53 +/- 10, and 29 +/- 10%, respectively. According to univariate analysis, extracranial controlled disease status (p = 0.03), and SIR (p = 0.04) were prognostic factors for overall survival. According to multivariate analysis, none was an independent prognosticator for overall survival. Complications were minimal. CONCLUSION: Radiosurgical treatment of brain metastases of melanoma is effective and accurate. The use of radiosurgery alone is an appropriate management strategy for many patients with brain metastases of melanoma.     

Salvage treatment for persistent and recurrent T1-2 nasopharyngeal carcinoma by stereotactic radiosurgery

OBJECTIVE: To study the efficacy of stereotactic radiosurgery in salvaging early-stage persistent and recurrent nasopharyngeal carcinoma (NPC) after primary radiotherapy. METHODS: A prospective single-arm study evaluating the response and outcome of patients with rT1-2 NPC treated by stereotactic radiosurgery. Eleven patients with rT1-2 were treated by radiosurgery between March 1998 and March 2000. Four patients were treated for persistent disease occurring within 4 months after primary radiotherapy, six were treated for first recurrence, and one for third recurrence. Six patients had rT1 disease and five had rT2 disease. Most patients had disease not amenable to brachytherapy, surgery, or external re-irradiation. The median target volume was 5.8 cc (range, 3.3-16.9). Radiosurgery was performed with multiple noncoplanar arcs of photon, with a median dose of 12.5 Gy delivered to the 80% isodose line (range, 12-14 Gy). Median follow-up time after radiosurgery was 18 months (range, 9-30). RESULTS: Nine patients had complete regression of tumor as assessed by imaging, nasopharyngoscopy, and biopsy; one patient had partial regression of tumor; whereas one patient had static disease. The overall response rate was 91% (10 of 11) and the complete response rate was 82% (9 of 11). Two patients with complete response subsequently had local relapse develop, with one recurrence outside the treated volume 8 months after radiosurgery, and the other within the treated volume 6 months after radiosurgery. One patient with a partial response had neck node recurrence develop. Temporal lobe necrosis occurred in one patient but probably represents sequelae of primary radiation after reviewing the dosimetry. Ten patients are still alive, whereas one patient with local relapse had distant metastases develop and died. The estimated 1-year local control rate after radiosurgery was 82%. CONCLUSIONS: Our preliminary results indicate that stereotactic radiosurgery is an effective treatment modality for persistent and recurrent T1-T2 NPC, and early control rate seems to be comparable to other salvage treatments. More clinical experiences and longer follow-up are still needed to validate our results and to address fully the role of radiosurgery in salvaging local failures of NPC.     

CyberKnife radiosurgery for vestibular schwannoma.

OBJECTIVE: The CyberKnife is newly developed equipment for radiosurgery and fractionated radiosurgery. The authors report on their experience using the CyberKnife in 38 patients with vestibular schwannoma who were treated between 1998 to 2002. METHODS: During this period, 38 patients with vestibular schwannoma were treated using CyberKnife fractionated radiosurgery. Before undergoing fractionated radiosurgery, 14 patients had Gardner Robertson classes I or II hearing (the serviceable hearing group), and 24 patients had classes III to V hearing (the non-serviceable hearing group). The treatment volumes of these two groups were 0.5 to 24.0 cm (3) (mean 4.7 cm (3)), and 0.5 to 41.6 cm (3) (mean 8.2 cm (3)). Target irradiation was administered in 1 - 3 fractions (mean 2.5 fractions). The total marginal radiation doses were 15.0 to 20.5 Gy (mean 17.0 Gy), and 11.9 to 20.1 Gy (mean 16.9 Gy), respectively. RESULTS: After a mean follow-up period of 31.9 months (range 12 to 59 months, median 27 months), 94 % of the tumors were controlled. Only one patient in the group with non-serviceable hearing underwent additional surgical resection for a presumed increase in tumor size. The hearing preservation rate was 93 %. Facial weakness did not develop in any of the patients in the serviceable hearing group. New trigeminal symptoms did not develop in any patients in either group. CONCLUSION: Although a longer and more extensive follow-up is needed, CyberKnife fractionated radiosurgery is considered to be safe and effective, even in patients with large tumors.     

Boost radiosurgery for treatment of brain metastases after surgical resections

BACKGROUND: We evaluated results of resection surgery followed by boost radiosurgery for the treatment of brain metastases. METHODS: We treated 21 patients (13 male, 8 female) with surgical resection (subtotal or total) followed by boost radiosurgery. The mean patient age was 61 years (range, 41-80 years); supratentorial lesions were treated in 12 patients, and posterior fossa lesions were treated in 9 patients. The most common primary cancers were lung (24%) and colon (24%). Fifty-three percent of patients had brain metastases only, whereas 47% had extracranial metastases. The radiosurgery dose plan was designed to radiate the operative cavity; the mean treatment volume (50% isodose) was 10.7 mL (range, 3.4-23.3 mL), and the mean marginal dose was 17 Gy (range, 13-20 Gy). RESULTS: Local control was achieved in 16 (76%) patients. However, new intracranial lesions developed in 10 patients, and meningeal carcinomatosis occurred in 5 patients. Local tumor recurrence occurred more often for patients treated with lower radiotherapy doses (<18 vs > or =18 Gy, P = .03), and meningeal carcinomatosis occurred more often in patients with posterior fossa lesions (P = 0.05). Gamma knife radiosurgery was performed in 13 patients, and whole-brain radiation was performed in 2 patients. No patients experienced symptomatic radiation injury, and the median survival time was 20 months. CONCLUSIONS: Although boost radiosurgery is less invasive and reduces morbidity, the radiosurgical dose must be higher than 18 Gy for the treatment to be most effective. Treatment of lesions of the posterior fossa must be considered carefully because of the higher frequency of meningeal carcinomatosis. Also, we recommend that the surgeons who operate on the metastatic tumors must try to decrease the resected cavity volume and to prevent cerebrospinal fluid dissemination at the operation for posterior fossa lesions.     

Stereotactic radiosurgery as an alternative to fractionated radiotherapy for patients with recurrent or residual nonfunctioning pituitary adenomas

OBJECTIVE: To evaluate tumor control rates and complications after stereotactic radiosurgery for patients with nonfunctioning pituitary adenomas. METHODS: Between 1992 and 2000, 33 patients underwent radiosurgery for treatment of nonfunctioning pituitary adenomas. Thirty-two patients (97%) had undergone one or more previous tumor resections. Twenty-two patients (67%) had enlarging tumors before radiosurgery. The median tumor margin dose was 16 Gy (range, 12-20 Gy). The median follow-up period after radiosurgery was 43 months (range, 16-106 mo). RESULTS: Tumor size decreased for 16 patients, remained unchanged for 16 patients, and increased for 1 patient. The actuarial tumor growth control rates at 2 and 5 years after radiosurgery were 97%. No patient demonstrated any decline in visual function. Five of 18 patients (28%) with anterior pituitary function before radiosurgery developed new deficits, at a median of 24 months after radiosurgery. The actuarial risks of developing new anterior pituitary deficits were 18 and 41% at 2 and 5 years, respectively. No patient developed diabetes insipidus. CONCLUSION: Stereotactic radiosurgery safely provides a high tumor control rate for patients with recurrent or residual nonfunctioning pituitary adenomas. However, despite encouraging early results, more long-term information is needed to determine whether radiosurgery is associated with lower risks of new endocrine deficits and radiation-induced neoplasms, compared with fractionated radiotherapy.     

Gamma knife radiosurgery for cavernous sinus metastases and invasion

BACKGROUND: We evaluated the efficacy of gamma knife radiosurgery for cavernous sinus metastases and invasion. METHOD: We treated and followed up 21 patients with cavernous sinus metastases and invasion using gamma knife radiosurgery. Nine of these patients had nasopharyngeal cancer, and 12 had distant metastases from other cancers. The volume of tumors ranged from 2.9 to 50.0 (median 9.9) mL. and the radiation dose to the tumor margin was 10 to 21 (median 14) Gy. RESULTS: The median follow-up period was 9 months. Clinical symptoms were improved in 48% of the patients after treatment, and tumor growth control was obtained in 67% of the patients at their final follow-up. The actual 1- and 2-year tumor growth control rates were 68% and 43%, respectively. The mean survival time was 13 months. No patient had radiation injury. CONCLUSION: Gamma knife radiosurgery is a very useful therapeutic option for the treatment of cavernous sinus metastases and invasion, either as initial treatment or as an adjunct treatment for recurrences even in preirradiated patients.     

Stereotactic radiosurgery as a salvage treatment for recurrent epipharyngeal carcinoma

Fourteen patients with recurrent epipharyngeal carcinoma (EPC) were treated by gamma knife stereotactic radiosurgery. The tumor volume ranged from 0.3 to 80 ml (median 18.9 ml). Treatment was done with a tumor margin dose of 10-27 Gy (median 15 Gy). The median follow-up period was 15 months (range 2-47 months). Ten patients were alive and 4 were dead at the end of the follow-up period. In 6 patients (43%), the tumor disappeared or decreased in size until the end of the follow-up period. In 2 (14%), the tumor remained unchanged in size. In 6 (43%), the tumor showed regression initially but was enlarged later. A second radiosurgery was performed in 4 of those 6 cases and the tumor decreased in size again in 3 of them. Thus, the overall control rate of local tumor was 79% (11/14). In selected patients with recurrent EPC, stereotactic radiosurgery can be considered as a salvage treatment producing local control.     

Radiosurgery for the treatment of spinal melanoma metastases

BACKGROUND: The role of stereotactic radiosurgery in treating metastatic melanoma involving the spine has previously been limited. Conventional external beam radiotherapy lacks the precision to allow delivery of large single-fraction doses of radiation and simultaneously to limit the dose delivered to radiosensitive structures such as the spinal cord. This study evaluated the clinical efficacy of radiosurgery for the treatment of melanoma spinal metastases in 28 patients. METHODS: Thirty-six melanoma spine metastases were treated with a single-session radiosurgery technique (1 cervical, 11 thoracic, 13 lumbar, and 11 sacral) with a follow-up period of 3-43 months (median 13 months). Tumor volume ranged from 4.1 to 153 cm3 (mean 47.6 cm3). Twenty-three of the 36 lesions had received prior external beam irradiation. RESULTS: Maximum tumor dose was maintained at 17.5-25 Gy (mean 21.7 Gy). Spinal cord volume receiving > 8 Gy ranged from 0.0 to 0.7 cm3 (mean 0.26 cm3); spinal canal volume at the cauda equina level receiving > 8 Gy ranged from 0.0 to 3.5 cm3 (mean 0.98 cm3). No radiation-induced toxicity occurred during the follow-up period. Axial and radicular pain improved in 27 of 28 patients (96%) who were treated primarily for pain. Long-term tumor control was seen in 3 of 4 cases treated primarily for radiographic tumor progression. Two patients went on to require open surgical intervention for tumor progression resulting in neurological deficit. CONCLUSIONS: Spinal radiosurgery offers a therapeutic modality for the safe delivery of large dose fractions of radiation therapy in a single fraction for the management of spinal metastases in patients with advanced melanoma that are often poorly controlled with alternative conventional external beam radiation therapy, and is successful even in patients with previously irradiated lesions.     

Management of vestibular schwannoma by fractionated stereotactic radiotherapy and associated cerebrospinal fluid malabsorption

OBJECT: The goal of this study was to investigate outcomes in patients with vestibular schwannoma (VS) who were treated with fractionated stereotactic radiotherapy (SRT). METHODS: One hundred one patients with VS were treated with fractionated SRT at a radiation level of 40 to 50 Gy administered in 20 to 25 fractions over a 5- to 6-week period. The median tumor size in these patients was 19 mm (range 3-40 mm), and 27 tumors were larger than 25 mm. Patients were consistently followed up using magnetic resonance imaging every 6 months for 5 years in principle. The median follow-up period was 45 months. The actuarial 5-year rate of tumor control (no growth > 2 mm and no requirement for salvage surgery) was 91.4% (95% confidence interval 85.2-97.6%). Three patients with progressive tumors underwent salvage tumor resection. The actuarial 5-year rate of useful hearing preservation (Gardner-Robertson Class I or II) was 71%. The observed complications of fractionated SRT included transient facial nerve palsy (4% of patients), trigeminal neuropathy (14% of patients), and balance disturbance (17% of patients). No new permanent facial weakness occurred after fractionated SRT. Eleven patients (11%) who had progressive communicating hydrocephalus (cerebrospinal fluid malabsorption) and no evidence of tumor growth after fractionated SRT required a shunt. The symptoms of this type of hydrocephalus were similar to those of normal-pressure hydrocephalus and occurred 4 to 20 months (median 12 months) after fractionated SRT. The mean size (+/- standard deviation) of tumors causing symptomatic hydrocephalus (25.5 +/- 7.8 mm) was significantly larger than that of other tumors (18.2 +/- 8.7 mm) (p = 0.011). Only four of the 72 patients with tumors smaller than 25 mm in maximum diameter received a shunt. CONCLUSIONS: Fractionated SRT resulted in an excellent tumor control rate, even for relatively large tumors, and produced a high rate of hearing preservation that was comparable to the best results of single-fraction radiosurgery. The progression of communicating hydrocephalus should be monitored closely, particularly in patients harboring a large VS.     

Radiosurgery for paraganglioma of the temporal bone

PURPOSE: To report the outcome of patients with paraganglioma of the temporal bone treated with stereotactic radiosurgery at the University of Florida. METHODS AND MATERIALS: Between January 1997 and June 1999, five patients with paraganglioma of the temporal bone were treated with Linac-based stereotactic radiosurgery at the University of Florida. The ages of the three female and two male patients were between 40 and 88 years (median, 49 years). Four patients were treated at initial presentation, and one had recurrent disease. Treatment volumes ranged from 4.9 cm3 to 18.4 cm3, with a mean of 10.84 cm3. The dose applied to the margin of the tumor varied from 12.5 to 15 Gy (median, 15 Gy). The treatment dose was specified to the 80% isodose shell in two cases and to the 70% isodose shell in three cases. The median follow-up time was 27 months, ranging from 14 to 50 months. RESULTS: One of four previously untreated patients had a relapse at the primary tumor site. Treatment failure occurred at the field margin 6 months after radiosurgery; the patient was subsequently treated with fractionated stereotactic radiotherapy and at the time of analysis had no evidence of disease, 21 months after initiation of salvage therapy. The patient treated at the time of recurrence after conventional radiotherapy had a local recurrence 40 months after radiosurgery. At the time of this recurrence, the patient had biopsy-proven metastatic disease in two cervical lymph nodes, and no salvage therapy was performed. All patients were alive at the time of the analysis, one with disease present. Presenting symptoms improved in two patients and stabilized in one. The two patients who had local recurrence develop had worsening of their symptoms. One patient had a cranial nerve V palsy develop 6 months after treatment, which resolved after a few months. CONCLUSIONS: In this series, the results with stereotactic radiosurgery are discouraging compared with our results with conventional fractionated radiotherapy in patients with paraganglioma of the temporal bone.     

Local control of brain metastases by stereotactic radiosurgery in relation to dose to the tumor margin

OBJECT: The maximal tolerated dose (MTD) for stereotactic radiosurgery (SRS) for brain tumors was established by the Radiation Therapy Oncology Group (RTOG) in protocol 90-05, which defined three dose groups based on the maximal tumor diameter. The goal in this retrospective study was to determine whether differences in doses to the margins of brain metastases affect the ability of SRS to achieve local control. METHODS: Between 1997 and 2003, 202 patients harboring 375 tumors that met study entry criteria underwent SRS for treatment of one or multiple brain metastases. The median overall follow-up duration was 10.7 months (range 3-83 months). A dose of 24 Gy to the tumor margin had a significantly lower risk of local failure than 15 or 18 Gy (p = 0.0005; hazard ratio 0.277, confidence interval [CI] 0.134-0.573), whereas the 15- and 18-Gy groups were not significantly different from each other (p = 0.82) in this regard. The 1-year local control rate was 85% (95% CI 78-92%) in tumors treated with 24 Gy, compared with 49% (CI 30-68%) in tumors treated with 18 Gy and 45% (CI 23-67%) in tumors treated with 15 Gy. Overall patient survival was independent of dose to the tumor margin. CONCLUSIONS: Use of the RTOG 90-05 dosing scheme for brain metastases is associated with a variable local control rate. Tumors larger than 2 cm are less effectively controlled than smaller lesions, which can be safely treated with 24 Gy. Prospective evaluations of the relationship between dose to the tumor margin and local control should be performed to confirm these observations.     

Radiosurgery to palliate symptoms in brain metastases from uterine cervix cancer

Background

The optimal management of brain metastases from uterine cervix cancer (UCC) is not well defined because of the rarity of the condition and the scarcity of published reports. Here we report our experience with stereotactic radiosurgery for the management of brain metastases from UCC.

Methods

Thirteen consecutive patients with brain metastases from UCC were managed with a Leksell gamma-knife at our institution between January 2003 and December 2010. Clinical features and radiosurgical outcomes of patients were analyzed retrospectively.

Results

Gamma-knife radiosurgery (GKRS) was chosen as the only treatment in four patients and performed in combination with whole-brain radiotherapy (WBRT) in nine patients. GKRS was conducted simultaneously with WBRT within a 1-month interval in six patients and was chosen as the salvage treatment after WBRT in three patients. The mean number of metastatic brain lesions per patient was 5.7 (range, 1–16). The median cumulative tumor volume was 23.7 cm³ (range, 2.7–40.2 cm³), and the median marginal dose covering the tumors was 14 Gy of a 50 % isodose line (range, 8–25 Gy). Nine patients showed relief of main neurologic symptoms after GKRS. The median length of time that the patients spent in an improved neurologic state was 11.1 weeks (range, 2–39.6 weeks). The local and distant control rates were 66.7 % and 77.8 %, respectively. The median survival from the date of GKRS until death was 4.6 months (range, 1.0–15.9 months). The 6-month and 12-month survival rates after GKRS were 38 and 15 %, respectively.

Conclusions

GKRS could be an efficient palliative measure to relieve neurologic symptoms caused by brain metastasis from UCC.     

Adjuvant stereotactic radiosurgery for anaplastic ependymoma

OBJECT: The purpose of this retrospective study is to evaluate the role of stereotactic radiosurgery using the Gamma Knife as an adjuvant to other modalities used in the treatment of malignant ependymomas of both children and adults and to assess its efficacy in terms of tumor control and overall survival. METHOD: Between 1987 and 1998, 22 patients in the age range of 1.5-65 years (mean age 22. 3) with progressive anaplastic ependymoma were treated by stereotactic radiosurgery using the 201 source Co-60 Leksell Gamma Knife at the University of Pittsburgh. The irradiated tumor volume varied from 0.84 to 36.8 cm(3) (mean 13.7). The median dose delivered to the tumor margin was 16.1 Gy (range 10-20), and the mean maximal dose was 32.2 Gy (range 20-40). The disease-free survival, the tumor control rate and the overall survival were recorded to evaluate the efficacy of radiosurgery. The median follow-up from radiosurgery was 21 months (range 4-84). RESULTS: Median survival after radiosurgery was 2.2 years (46.6 +/- 12.1% 5-year actuarial). Median survival from the initial diagnosis was 10. 1 years (50.3 +/- 12.5% at 5 years, 37.7 +/- 14.4% at 10 years). Reduction or stabilization of the treated tumor was seen in 16 out of 22 (68%) patients. Forty-one percent of the patients eventually developed delayed distant cerebral recurrence outside the treated volume. The 5-year actuarial rates for local control and cranial control at any location were 62.3 +/- 13.6% and 32.4 +/- 10.8%, respectively. No complication occurred as a side effect of radiosurgery. CONCLUSION: For patients with locally recurrent or progressive anaplastic ependymomas, Gamma Knife stereotactic radiosurgery proved to be safe and effective as a salvage adjuvant therapy to achieve local tumor control and improve survival.     

The role of tumor size in the radiosurgical management of patients with ambiguous brain metastases

OBJECTIVE: To identify a size cutoff below which it is safe to observe obscure brain lesions suspected of being metastases so that treatment of nonmetastases can be avoided. METHODS: Medical records from patients who underwent linear accelerator-based radiosurgery from August 1991 to October 2001 were reviewed. Inclusion criteria were defined as brain metastasis tumor volume less than 5 cm(3) (diameter, thick similar 2.1 cm) treated with a dose of 20 Gy or more. One hundred thirty-five patients had 153 evaluable brain metastases with follow-up imaging that met inclusion criteria. Median age was 54 years (range, 18-79 yr). Lesion primaries were non-small-cell lung (n = 39), melanoma (n = 44), renal (n = 37), breast (n = 18), colon (n = 3), sarcoma (n = 5), other (n = 5), and unknown primary (n = 2). Median tumor volume was 0.67 cm(3) (range, 0.06-4.58 cm(3)). The minimum peripheral dose was 20 Gy (n = 132) or 21 to 24 Gy (n = 21). At the time of analysis, the median follow-up for all patients was 10 months (range, 0.2-99 mo). RESULTS: The 1- and 2-year actuarial local control rates for all of the lesions were 69 and 46%, respectively. For lesions of 1 cm (0.5 cm(3)) or less, the corresponding local control rates were 86 and 78%, respectively, which was significantly higher than the corresponding rates of 56 and 24%, respectively, for lesions larger than 1 cm (0.5 cm(3)) (P = 0.0016). CONCLUSION: A convincing brain metastasis measuring less than 1 cm should be pursued aggressively. If the suspected brain metastasis is ambiguous, observation is proposed up to a diameter of 1 cm. This is the first study in the literature to identify a 1-cm cutoff for radiosurgical control of small brain metastases, and validation by additional studies is required.     

LINAC Radiosurgery for Patients with a Limited Number of Brain Metastases

Patients (pts) with brain metastases have a high risk of cancer-related death due to extra- or intracranial tumor manifestations. The present retrospective analysis demonstrates the ability of linear accelerator (LINAC)-based radiosurgery to control intracranial disease and prolong survival in pts with one to three metastases. From 1991 to 1996, 106 pts (42 females, 64 males; median age, 57 years) with cerebral metastases were treated by stereotactic radiosurgery with a LINAC (8 MeV) equipped with tertiary collimators. In 70 pts, a single metastasis was present; 36 pts had two or three metastases. Fifty-nine pts were treated for their first occurrence of brain metastases; 47 pts had been treated prior to radiosurgery by resection and/or whole-brain irradiation. Histology of the primary tumor was non–small cell lung cancer (36 pts), melanoma (20 pts), breast cancer (15 pts), hypernephroma (15 pts), and other (20 pts). All together, 157 metastases (0.04–69.0 ml; median, 2.7 ml) were irradiated with marginal doses of 12–25 Gy (median, 20 Gy) referred to the 65–80% isodose. Seventy-two percent of the lesions were treated with a single isocenter. Adjuvant whole-brain irradiation was applied in six pts. One hundred thirty-five of 157 metastases were evaluated for response: complete response (CR), 24%; partial response, 31%; no change, 30%; and progression of disease, 15%. CR rates were highest (48%) in small metastases (<1-cm diameter), independent of histological type and dose. The overall median survival was 8 months. Multivariate Cox regression analysis revealed a significant impact on survival for Karnofsky performance score, presence of extracranial tumor, and volume of largest metastasis. Freedom from neurological death was determined only by the volume of the largest metastasis. Patients with multiple metastases and/or extracranial disease had a higher risk of developing new outfield brain metastases. Due to salvage therapy (second or third course of stereotactic radiosurgery, whole-brain irradiation, surgery), the overall survival in pts with two or three metastases did not significantly differ from that in pts with single metastases. LINAC-based stereotactic radiosurgery in pts with up to three cerebral metastases results in survival rates approaching those of pts with resected single brain metastases. As pts with both single and multiple metastases can effectively be salvaged after receiving radiosurgery, extracranial tumor activity becomes a major determinator of survival.     

Stereotactic radiosurgery in the management of acoustic neuromas associated with neurofibromatosis Type 2

OBJECT: Stereotactically guided radiosurgery is one of the primary treatment modalities for patients with acoustic neuromas (vestibular schwannomas). The goal of radiosurgery is to arrest tumor growth while preserving neurological function. Patients with acoustic neuromas associated with neurofibromatosis Type 2 (NF2) represent a special challenge because of the risk of complete deafness. To define better the tumor control rate and long-term functional outcome, the authors reviewed their 10-year experience in treating these lesions. METHODS: Forty patients underwent stereotactic radiosurgery at the University of Pittsburgh, 35 of them for solitary tumors. The other five underwent staged procedures for bilateral lesions (10 tumors, 45 total). Thirteen patients (with 29% of tumors) had undergone a median of two prior resections. The mean tumor volume at radiosurgery was 4.8 ml, and the mean tumor margin dose was 15 Gy (range 12-20 Gy). The overall tumor control rate was 98%. During the median follow-up period of 36 months, 16 tumors (36%) regressed, 28 (62%) remained unchanged, and one (2%) grew. In the 10 patients for whom more than 5 years of clinical and neuroimaging follow-up results were available (median 92 months), five tumors were smaller and five remained unchanged. Surgical resection was performed in three patients (7%) after radiosurgery; only one showed radiographic evidence of progression. Useful hearing (Gardner-Robertson Class I or II) was preserved in six (43%) of 14 patients, and this rate improved to 67% after modifications made in 1992. Normal facial nerve function (House-Brackmann Grade 1) was preserved in 25 (81%) of 31 patients. Normal trigeminal nerve function was preserved in 34 (94%) of 36 patients. CONCLUSIONS: Stereotactically guided radiosurgery is a safe and effective treatment for patients with acoustic tumors in the setting of NF2. The rate of hearing preservation may be better with radiosurgery than with other available techniques.