Traitement des métastases cérébrales par radiochirurgie stéréotaxique : étude de 33 cas liés à un accident de « surexposition »

The consequences of a dosimetric radiosurgery accident are not the same as a conventional radiotherapy accident. The objective of this study was to estimate the clinical and radiological outcome of patients treated by radiosurgery for metastasis during the period of the overexposure accident that occurred in the Toulouse Radiosurgery Unit. Between April 2006 and March 2007, 33 patients with 57 metastases were treated in the Toulouse Radiosurgery Unit (Novalis^®, BrainLab). An initial error in the estimation of the scatter factors led to an overexposure to radiation. The median age was 55 years [range, 35-85]. Twenty-one patients (64%) harbored a single metastasis. The primary tumor location was lung (16 cases), kidney (nine cases), breast (four cases), and others (four cases). The mean tumoral volume was 3.2 cm³ [0.04-14.07]. The mean prescribed dose at the isocenter was 20 Gy [range, 10-23], the mean delivered dose was 31.5 Gy [range, 13-52], and the mean overdose was 61.2% [range, 5.6-226.8]. In order to evaluate the consequences of the overdose, three parameters were analyzed: a risk index using dose and volume, the volume of parenchyma that received more than 12 Gy, and the mean dose in a sphere of 20 cm³ surrounding the target volume. Median actuarial survival was 14.1 months, the survival rate was 79.4 % at six months, 59.1% at 12 months, and 27.2% at 24 months. The rate of tumor control was 80.7%. No morbidity was observed. There was no correlation between death and the parameters studied. The survival rates and times observed in our study of the patients treated for brain metastases by radiosurgery and overexposed were among the good results of the international literature. Deaths were not related to the overdose and no side effect was noted. This dosimetric accident has not had worse consequences in this population.     

Single-Fraction Radiosurgery for Primary and Recurrent Malignant Gliomas

From November 1990 to May 1993, 37 patients with malignant gliomas were treated with single-fraction radiosurgery. Nineteen patients had newly diagnosed tumors. Twelve of these were gliob-lastoma multiforme (GBM) and 7 were anaplastic astrocytoma (AA). Tumors were recurrent after standard radiotherapy in 18 patients. Twelve were GBM and 6 were AA. Median ages were 56 years for those with primary tumors and 52 years for those with recurrent tumors. Strict neuroimaging criteria were not used to select patients for radiosurgery. Median tumor volumes for primary GBM and AA were 15 cc and 9.4 cc, respectively. Median volumes for recurrent GBM and AA were 22.6 cc and 19.6 cc, respectively. Karnofsky Performance Status was above 60% in all patients. Median tumor minimum doses were 30 Gy for primary tumors and 27 Gy for recurrent tumors. Median tumor maximum doses were 50 Gy and 55 Gy, respectively. Median follow-up was 14 months for primary glioma patients and 7.5 months for those with recurrent tumors. Survival analysis was performed using the Kaplan–Meier method. Comparison of prognostic factors was performed using the log-rank and Wilcoxon tests No patient in this series remains alive. Median survivals of those with primary GBM and AA were 13 and 12 months, respectively, from diagnosis. Median survivals of those with recurrent GBM and AA were 7 and 8 months, respectively, from the date of radio-surgery. Thirty-three of 37 patient deaths were due to tumor progression within the radiosurgery treatment volume. Tumor recurred outside the high-dose volume of radiosurgery in 3 patients. Acute complications necessitating hospitalization occurred in 3 patients. Fourteen patients (38%) became dependent on corticosteroids after radiosurgery. Six patients (16%) were resected after radiosurgery. Coagulative necrosis and morphologically intact tumor cells were identified in all resected patients. There was no significant influence of the following factors on actuarial survival of primary or recurrent tumors: age, gender, tumor volume, tumor location, duration from conventional radiotherapy, or radiosurgery dose. Tumor volume was a predictor of reoperation for AA. Indiscriminate application of radiosurgery in this series did not increase the survival of patients with primary or recurrent GBM. Central recurrence represents the predominant form of relapse when patients with malignant gliomas receive radiosurgery in the absence of imaging selection criteria. These criteria include tumor volume and evidence for a discreet lesion. Radiosurgery planning should provide a margin of normal brain parenchyma. Advances in tumor imaging and radiosurgery techniques may improve results of this unique modality for patients with malignant gliomas.     

Treatment of Cavernous Sinus Tumors with Linear Accelerator Radiosurgery

Since 1989, 79 patients with benign or malignant cavernous sinus tumors, have been treated at Stanford University with linear accelerator (linac) radiosurgery. Radiosurgery has been used as (1) a planned second-stage procedure for residual tumor following surgery, (2) primary treatment for patients whose medical conditions preclude surgery, (3) palliation of malignant lesions, and (4) definitive treatment for small, well-localized, poorly accessible tumors. Mean patient age was 52 years (range, 18 to 88); there were 28 males and 51 females. Sixty-one patients had benign tumors; 18 had malignant tumors. Mean tumor volume was 6.8 cm³ (range 0.5 to 22.5 cm³) covered with an average of 2.3 isocenter (range, 1 to 5). Radiation dose averaged 17.1 Gy. Mean follow-up was 46 months. Tumor control or shrinkage, or both, varied with pathology. Radiographic tumor improvement was most pronounced in malignant lesions, with greater than 85% showing reduction in tumor size; benign tumors (meningiomas and schwannomas) had a 63% control rate and 37% shrinkage rate, with none enlarging. We concluded that stereotactic radiosurgery is a valuable tool in managing cavernous sinus tumors. There was excellent control and stabilization of benign tumors and palliation of malignant lesions.     

LINAC radiosurgery for brain metastasis of renal cell carcinoma

The purpose of the study was to evaluate the efficacy and toxicity of stereotactic radiotherapy in the treatment of the brain metastasis of renal cell carcinoma. From 1994 to 2001, 28 patients presenting with 65 metastases of renal cell cancer were treated by radiosurgery. Median age was 55 years (35-75), and median Karnofski performance status ranges between 50 and 100. Seven patients had received whole brain radiotherapy (WBRT) before radiosurgery. Twelve patients were treated by radiosurgery for 1 metastasis, 5 patients for two metastases and 6 for three, and 5 for more than three metastases. One procedure was performed in 22 patients and, 2 or 3 procedures for 6 patients. Median metastasis diameter was 19 mm (5-55 mm). Median metastasis volume was 1.28 cc (0.02-28 cc). Irradiation was delivered by linear accelerator. Median minimal dose (on the 70% isodose) was 14.7 Gy (10.8 Gy, 19.5 Gy), median maximal dose (at the isocenter) 20.5 Gy (14.3 Gy, 39.6 Gy). Median follow-up was 14 months (1-33). Two metastases progressed (3%), 2 and 12 months after radiosurgery. Overall, crude local control rate was 97% and 3-, 6- and 12-month local control rates were 98% +/- 2%, 98% +/- 2%, and 93% +/- 5%, respectively. In univariate analysis, no prognostic factor of local control was retrieved. Median brain disease-free survival was 25 months after RS. the 3-, 6- and 12-month distant brain control rates were 91% +/- 4%, 91% +/- 4%, and 70% +/- 12%, respectively. Median survival duration was 11 months. The 3-, 6-, 12- and 24-month overall survival rates were 82% +/- 7%, 67% +/- 9%, 48% +/- 10%, and 33% +/- 10%, respectively. According to univariate analysis, only site of metastasis was overall survival prognostic factor. Radiosurgery for brain metastasis of renal cell carcinoma is an effective and accurate treatment. The use of radiosurgery alone is an appropriate management strategy for many patients with brain metastasis of renal cell carcinoma. Radiosurgery is efficient even after development of new metastasis appearing after WBRT.     

Radiosurgery for the treatment of recurrent central neurocytomas

OBJECTIVE: Central neurocytomas are benign neoplasms with neuronal differentiation typically located in the lateral ventricles of young adults. Although the treatment of choice is complete surgical excision, patients may experience local recurrence. Adjuvant therapy for patients with residual or recurrent tumor has included reoperation, radiotherapy, or chemotherapy. To avoid the side effects of conventional radiotherapy in young patients, we present a series of patients with clear evidence of tumor progression who were treated with gamma knife radiosurgery. METHODS: Four patients (ages 20-49 yr; mean, 28 yr) who presented with an intraventricular mass on magnetic resonance imaging scans and underwent craniotomy for tumor resection were reviewed retrospectively. Histopathological analysis confirmed central neurocytoma in all cases. Each patient was followed up clinically and radiographically with serial magnetic resonance imaging. When radiographic signs of tumor progression were evident, patients were treated with radiosurgery. RESULTS: Complete radiographic tumor resection was achieved in all patients. There were no major postoperative complications. Local tumor progression was detected on magnetic resonance imaging scans 9 to 25 months after surgery (median, 17.5 mo). All patients achieved complete response to radiosurgery with reduction in tumor size. There have been no complications from radiosurgery. Follow-up ranged from 12 to 28 months (mean, 16.5 mo) after radiosurgery, and from 24 to 84 months (mean, 54.5 mo) after initial presentation. CONCLUSION: Radiosurgery with the gamma knife unit provides safe and effective adjuvant therapy after surgical resection of central neurocytomas. Radiosurgery may eliminate the need for reoperation and avoid the possible long-term side effects from conventional radiotherapy in young patients.     

Survival after Stereotactic Radiosurgery for Recurrent Glioblastoma Multiforme

This retrospective analysis details the experience of a tertiary care center with survival and results for patients with recurrent glioblastoma multiforme (GBM) treated with stereotactic radiosurgery (SRS). Between August 1990 and June 1999, 23 patients were treated for recurrent GBM with SRS using either modified 6-MV linear accelerator (linac) or -knife. Twenty-two patients (96%) had an initial histological diagnosis of GBM, while 1 patient had an initial diagnosis of anaplastic astrocytoma that was biopsied at recurrence and found to have upgraded to GBM. The median Karnofsky performance score at the time of SRS was 80; the median age was 53. The median-treated tumor volume was 9.9 cm³, with a dose of 15 Gy delivered to the 60% isodose line. Median progression-free survival was 4.7 months. Median survival time after SRS was 10.3 months. No prognostic factors were found to be significant. Patients with a KPS of 80 or higher had longer median survival times than those with lower KPS scores, but this was not found to be statistically significant. Our results suggest that for selected patients with recurrent GBM, SRS appears to be an appropriate salvage therapy.     

Modern robot-assisted radiosurgery of cerebral angiomas—own experiences,system comparisons,and comprehensive literature overview

Cerebral arteriovenous malformations (AVMs) are rare vascular lesions potentially responsible for substantial neurological morbidity and mortality. Over the past four decades, radiosurgery has become a valid therapeutic option for many patients with small intracranial AVMs, but reports describing the use of robotic stereotactic radiosurgery (SRS) are rare. The purposes of this study are to describe the efficacy and toxicity of robotic SRS for AVMs and to review the literature. The reports of 48 consecutive patients treated with SRS were reviewed. A total dose of 18 Gy in a single fraction was prescribed to the 70% isodose line. Efficacy (i.e., total obliteration of the AVM) and toxicity were analyzed. Literature search was performed on Embase and PubMed for the terms “Radiosurgery and AVMs”, “Cyberknife and AVMs” and “Radiation therapy and AVMs.” The median follow-up was 41 months. The median AVM volume was 2.62 cm³. The incidence of obliteration was 59% at 3 years. Regarding toxicity, 92% of patients remained symptom-free, 66% developed radiogenic edema on MRI, and none developed radionecrosis. Forty-one patients (85%) had embolization prior to SRS. Our study was incorporated in an exhaustive review of 25 trials categorized by SRS technique. In this review, the median follow-up was 60 months. The median nidus volume was 2 cm³. The median overall obliteration rate for SRS was 68% (range 36 to 92). The median embolization rate prior to SRS was 31% (range 8.23 to 90). Compared to other studies, tolerability was excellent and the obliteration rate was acceptable but probably affected by the high embolization rate prior to radiosurgery. Our study suggests that a higher dose is feasible. A larger cohort with a longer follow-up period will be needed to confirm the safety and effectiveness, and subsequently validate different prognosis and predictive scores with this treatment modality to maximize the benefits of this technology for selected patients in the long term.     

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.     

Gamma knife radiosurgery for trigeminal schwannomas

BACKGROUND: Trigeminal schwannomas are uncommon tumors that may be microsurgically removed in selected cases, albeit with significant risk for new neurological morbidity. We evaluated the role of stereotactic radiosurgery as an alternative for patients with newly diagnosed or residual trigeminal schwannomas. METHODS: The records of 23 patients who underwent radiosurgery for trigeminal schwannoma were reviewed. The most frequent presenting symptoms were facial numbness (11 patients), diplopia (6 patients), and facial pain (3 patients). One patient presented with partial complex seizures as the first symptom. Twelve patients had undergone one or more prior resections. Eleven underwent radiosurgery on the basis of imaging diagnosis only. The mean tumor volume was 4.5 mL (range 0.46-11.2 cc). Radiosurgery was performed using a median marginal dose of 15 Gy (range, 13-20 Gy). RESULTS: At a median imaging follow-up of 40 months (range, 12-146), 20 of 22 evaluable patients (91%) had tumor growth control (regression in 15 and no further tumor growth in 5). One 80-year-old patient died of unrelated cause 4 months after radiosurgery. Two patients with enlarged tumors were treated effectively with repeat radiosurgery. Twelve of 23 patients (52%) reported improvement and 9 (39%) had no change in their symptoms. Two patients noted new neurological complaints (transient facial weakness in 1 patient and worsening of the preradiosurgery facial numbness in another patient). CONCLUSIONS: Radiosurgery is an effective minimally invasive management option for patients with residual or newly diagnosed trigeminal schwannomas.     

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.     

Gamma Knife Radiosurgery of Meningiomas in the Cavernous Sinus Region

Summary  For 6 years (1992–1998) we have treated 67 patients with cavernous sinus meningioma using the Leksell gamma knife in the Hospital Na Homolce, Prague. The age of the patients ranged between 19–82 years, median 57 years. Radiosurgery was the primary treatment in 64,2% of the patients, in the rest a microsurgical resection preceded. The volume of the tumour ranged from 0,9–31,4 cm³, median 7,8 cm³. The meningioma was distant from the optic tract in 58% of the cases, in 12% of the cases there was a contact with the tumour and the optic tract without its compression and in 30% of the cases there was a compression of the optic tract caused by the meningioma. The dose to the tumour margin ranged from 10–14 Gy, median 12 Gy. The follow up was available in 53 patients, in intervals of 2–60 months, median 19 months. There was no change in the tumour volume in 48% of the cases, in 52% of the cases a decrease of the tumour volume occurred. No increase of the tumour volume was observed. Clinical symptoms and signs improved in 35,8% of the patients, temporary morbidity was 3,8%. The mortality of the treatment was zero.  Hitherto, the results of gamma knife radiosurgery of cavernous sinus meningioma have proved its safety and efficiency, although long term experience with a large group of patients is missing. Advances in neuroradiology and radiosurgical technique have allowed us to treat tumours with a closer contact to the optic tract and nerves compared with the past.     

Gamma Knife Radiosurgery for Glomus Jugulare Tumours

Summary  The aim of this clinical study was to determine the tumour control rate, clinical outcome and complication rate following gamma knife treatment for glomus jugulare tumours. Between May 1992 and May 1998, 13 patients with glomus tumours underwent stereotactic radiosurgical treatment in our department. The age of these patients ranged from 21 to 80 years. The male : female ratio was 2 : 11. Six patients had primary open surgery for partial removal or recurrent growth and subsequent radiosurgical therapy. Radiosurgery was performed as primary treatment in 7 cases. The median tumour volume was 6,4 cm³ (range: 4,6–13,7 cm³). The median marginal dose applied to an average isodose volume of 50% (30–50%) was 13,5 Gy (12–20 Gy). In 10 patients, a total of 48 MRI and CT follow-up scans were available. The remaining three patients have been excluded from the postradiosurgical evaluation since the observation time (t<12 months) was too short or patients were lost to follow up. The median interval from Gamma Knife treatment to the last radiological follow-up was 37,6 months (5–68 months). In 4 patients (40%) decreased tumour volumes were observed and in 6 cases (60%) the tumour size remained unchanged. Neurological follow-up examinations revealed improved clinical status in 5 patients (50%), a stable neurological status in 5 patients (50%) and no complications occurred. According to our preliminary experience Gamma Knife radiosurgery represents an effective treatment option for glomus jugulare tumours.     

Hypofractionated Stereotactic Radiotherapy for Malignant Glioma: A Phase I/II Study

In order to shorten treatment time for patients with newly diagnosed supratentorial malignant glioma, a phase I study of LINAC-based hypofractionated stereotactic radiotherapy (SRT) was initiated in September 1991. Nineteen adult patients entered the study. They were treated with 23 MV photons using a single-isocenter arc technique. Six patients received 5 × 5 Gy, 11 received 5 × 6 Gy, and 2 received 5 × 7 Gy over 1 week. Treatment plans were normalized to 100% at the isocenter. Target volume encompassed the tumor with a margin of 1.5–2 cm and was surrounded by the 80% isodose. Five patients had anaplastic astrocytoma and 14 had glioblastoma multiforme. Median tumor volume before SRT was 20.4 cm³. A matching group of 19 patients who received conventionally fractionated radiotherapy (CFRT) was selected in order to compare time to progression and survival. CFRT was applied with daily fractions of 2 Gy up to 60 Gy in 6 weeks. No chemotherapy was given. Seven of 19 patients developed acute grade III or IV toxicity (RTOG central nervous system toxicity criteria) and had to be treated with high-dose steroids and/or mannitol within 8 weeks after SRT (1 of 6 after 5 × 5 Gy, 5 of 11 after 5 × 6 Gy, and 1 of 2 after 5 × 7 Gy). In contrast, only 2 patients had signs of late toxicity. No radionecrosis was observed. Median time to progression was 5 months, median survival 7 months (CFRT: 7 and 11 months, p>0.1). One-year survival rate was 32% versus 37%. However, it was 0% after 5 × 5 Gy, but 40% after 5 × 6 or 7 Gy (p = 0.06). In conclusion, toxicity of SRT with 5 × 6 or 7 Gy was not acceptable. The 5 × 5 Gy regimen was tolerable, but not effective with regard to time to progression and overall survival.     

Optimal dose of stereotactic radiosurgery for acoustic neuromas: A systematic review

Radiosurgery is increasingly employed in the treatment of acoustic neuroma, but the optimal dose in terms of long-term tumour control and minimal adverse effects has not been established. We performed a systematic review of the published literature of radiosurgery of acoustic neuroma to assess whether the use of low dose radiosurgery is as effective as high dose treatment. Reports of radiosurgery for acoustic neuroma were identified through a Medline search. Studies with at least 15 patients and a median follow-up longer than 12 months were included. The relationship between actuarial 5-year progression-free survival (PFS), and tumour and treatment parameters was examined. Forty-two studies were included. Tumour control following lower radiosurgery doses was similar to that reported following high doses. Only 12 studies reported actuarial outcomes at 5 years. There was no relationship between PFS at 5 years and dose to the tumour margin. Radiosurgery of larger tumours was associated with lower 5 year PFS (p < 0.05). Although on initial inspection radiosurgery of acoustic neuroma with doses of 12 - 13 Gy seems to be as effective as higher dose treatment, the available reports are subject to a number of confounding factors, are not sufficiently statistically powered and there is only limited long-term actuarial outcome data. Currently, available studies do not provide sufficient confidence to support the claim that low dose radiosurgery is equally effective as higher doses in the long-term control of acoustic neuroma.     

Surgery and radiotherapy compared with gamma knife radiosurgery in the treatment of solitary cerebral metastases of small diameter.

OBJECT: The aim of this retrospective study was to compare treatment results of surgery plus whole-brain radiation therapy (WBRT) with gamma knife radiosurgery alone as the primary treatment for solitary cerebral metastases suitable for radiosurgical treatment. METHODS: Patients who had a single circumscribed tumor that was 3.5 cm or smaller in diameter were included. Treatment results were compared between microsurgery plus WBRT (52 patients, median tumor dose 50 Gy) and radiosurgery alone (56 patients, median prescribed tumor dose 22 Gy). In case of local/distant tumor recurrence in the radiosurgery group, additional radiosurgical treatment was administered in patients with stable systemic disease. Survival time was analyzed using the Kaplan-Meier method, and prognostic factors were obtained from the Cox model. The patient groups did not differ in terms of age, gender, pretreatment Karnofsky Performance Scale (KPS) score, duration of symptoms, tumor location, histological findings, status of the primary tumor, time to metastasis, and cause of death. Patients who suffered from larger lesions underwent surgery (p < 0.01). The 1-year survival rate (median survival) was 53% (68 weeks) in the surgical group and 43% (35 weeks) in the radiosurgical group (p = 0.19). The 1-year local tumor control rates after surgery and radiosurgery were 75% and 83%, respectively (p = 0.49), and the 1-year neurological death rates in these groups were 37% and 39% (p = 0.8). Shorter overall survival time in the radiosurgery group was related to higher systemic death rates. A pretreatment KPS score of less than 70 was a predictor of unfavorable survival. Perioperative morbidity and mortality rates were 7.7% and 1.6% in the resection group, and 8.9% and 1.2% in the radiosurgery group, respectively. Four patients presented with transient radiogenic complications after radiosurgery. CONCLUSIONS: Radiosurgery alone can result in local tumor control rates as good as those for surgery plus WBRT in selected patients. Radiosurgery should not be routinely combined with radiotherapy.     

Image-guided radiosurgery of head and neck cancers

OBJECTIVES: Radiosurgery precisely delivers a single high dose or a few fractionated doses of radiation to a localized tumor via the stereotactic approach. Some head and neck sites are suitable for radiosurgery since there is minimal or no organ motion. The clinical studies were carried out to determine the accuracy of stereotactic radiosurgery and to demonstrate the effectiveness of radiosurgery in head and neck cancers. MATERIALS AND METHODS: Thirteen patients were treated with either single-dose or fractionated radiosurgery to the tumor. All patients except one with cancer of the lip had received prior treatments including surgery, radiotherapy, and chemotherapy for the primary cancers. The dose ranged 12 to 18 Gy for single-dose radiosurgery and 30 Gy in 5 or 6 fractions twice a week for fractionated radiosurgery. Tumor localization was achieved via the stereotactic approach. RESULTS: Accuracy of radiosurgery was within 1.5 mm. Despite the recurrent disease from previous heavy treatments, 9 patients (70%) showed a significant response (complete or >50% tumor reduction) to radiosurgery, and 3 patients had stable disease. Complete tumor response was achieved in 6 patients. All patients had excellent pain relief with functional and cosmetic preservation. There was no acute and subacute radiation toxicity detected clinically during the minimal follow-up of 6 months. CONCLUSION: Image-guided radiosurgery is effective in achieving the local tumor control and pain relief. Radiosurgery provided excellent functional and cosmetic preservation with minimal complication. The results indicate the potential of radiosurgery in the treatment of recurrent and selected primary head and neck cancers.     

Intraoperative radiation therapy for malignant glioma.

Intraoperative radiation therapy (IORT) was used as part of the initial therapy for malignant glioma in 32 of 73 patients with histologically verified anaplastic astrocytoma (grade III astrocytoma) and glioblastoma multiforme. The initial treatment for all cases was subtotal or total tumor resection combined with external irradiation and chemotherapy. IORT was performed 1 week after tumor resection, with doses of 10-50 Gy (mean 26.7 Gy) in one session. Fourteen of 32 cases had IORT two times because of tumor recurrence. The IORT patients had survival rates at 24 and 36 months after initial treatment of 57.1 and 33.5% (median survival 26.2 months). The other 41 patients had 23.6 and 13.1% survivals (median survival 20.7 months), which were significantly lower (p less than 0.01). Tumor recurrence within the original lesion site was suspected because of clinical condition, computed tomography, and magnetic resonance imaging studies in 65.6% of the IORT group (21 cases) 12 months after initial treatment. Twenty cases of death in the IORT group, including five autopsy cases, demonstrated regional tumor recurrence with a high incidence of intraventricular tumor invasion. The authors consider IORT is beneficial for selected malignant glioma patients, including tumor recurrence, because of prolonged survival.     

Results of acoustic neuroma radiosurgery: an analysis of 5 years' experience using current methods

OBJECT: The goal of this study was to define tumor control and complications of radiosurgery encountered using current treatment methods for the initial management of patients with unilateral acoustic neuroma. METHODS: One hundred ninety patients with previously untreated unilateral acoustic neuromas (vestibular schwannomas) underwent gamma knife radiosurgery between 1992 and 1997. The median follow-up period in these patients was 30 months (maximum 85 months). The marginal radiation doses were 11 to 18 Gy (median 13 Gy), the maximum doses were 22 to 36 Gy (median 26 Gy), and the treatment volumes were 0.1 to 33 cm3 (median 2.7 cm3). The actuarial 5-year clinical tumor-control rate (no requirement for surgical intervention) for the entire series was 97.1+/-1.9%. Five-year actuarial rates for any new facial weakness, facial numbness, hearing-level preservation, and preservation of testable speech discrimination were 1.1+/-0.8%, 2.6+/-1.2%, 71+/-4.7%, and 91+/-2.6%, respectively. Facial weakness did not develop in any patient who received a marginal dose of less than 15 Gy (163 patients). Hearing levels improved in 10 (7%) of 141 patients who exhibited decreased hearing (Gardner-Robertson Classes II-V) before undergoing radiosurgery. According to multivariate analysis, increasing marginal dose correlated with increased development of facial weakness (p = 0.0342) and decreased preservation of testable speech discrimination (p = 0.0122). CONCLUSIONS: Radiosurgery for acoustic neuroma performed using current procedures is associated with a continued high rate of tumor control and lower rates of posttreatment morbidity than those published in earlier reports.     

Treatment of patients with primary glioblastoma multiforme with standard postoperative radiotherapy and radiosurgical boost: prognostic factors and long-term outcome.

OBJECT: To assess the value of stereotactic radiosurgery (SRS) as adjunct therapy in patients suffering from glioblastoma multiforme (GBM), the authors analyzed their experience with 78 patients. METHODS: Between June 1988 and January 1995, 78 patients underwent SRS as part of their initial treatment for GBM. All patients had undergone initial surgery or biopsy confirming the diagnosis of GBM and received conventional external beam radiotherapy. Stereotactic radiosurgery was performed using a dedicated 6-MV stereotactic linear accelerator. Thirteen patients were alive at the time of analysis with a median follow-up period of 40.8 months. The median length of actuarial survival for all patients was 19.9 months. Twelve- and 24-month survival rates were 88.5% and 35.9%, respectively. Patient age and Radiation Therapy Oncology Group (RTOG) class were significant prognostic indicators according to univariate analysis (p < 0.05). Twenty-three patients aged younger than 40 years had a median survival time of 48.6 months compared with 55 older patients who had 18.2 months (p < 0.001). Patients in this series fell into RTOG Classes III (27 patients), IV (29 patients), or V (22 patients). Class III patients had a median survival time of 29.5 months following diagnosis; this was significantly longer than median survival times for Classes IV and V, which were 19.2 and 18.2 months, respectively (p = 0.001). Only patient age (< 40 years) was a significant prognostic factor according to multivariate analysis. Acute complications were unusual and limited to exacerbation of existing symptoms. There were no new neuropathies secondary to SRS. Thirty-nine patients (50%) underwent reoperation for symptomatic necrosis or recurrent tumor. The rate of reoperation at 24 months following SRS was 54.8%. CONCLUSIONS: The addition of a radiosurgery boost appears to confer a survival advantage to selected patients.