Fractionated stereotactic conformal radiation therapy of brain stem gliomas: outcome and prognostic factors

Overview of the microanatomy of the human brainstem in relation to the safe entry zones

OBJECTIVE

The primary objective of this anatomical study was to apply innovative imaging techniques to increase understanding of the microanatomical structures of the brainstem related to safe entry zones. The authors hypothesized that such a high-detail overview would enhance neurosurgeons' abilities to approach and define anatomical safe entry zones for use with microsurgical resection techniques for intrinsic brainstem lesions.

METHODS

The brainstems of 13 cadavers were studied with polarized light imaging (PLI) and 11.7-T MRI. The brainstem was divided into 3 compartments-mesencephalon, pons, and medulla-for evaluation with MRI. Tissue was further sectioned to 100 μm with a microtome. MATLAB was used for further data processing. Segmentation of the internal structures of the brainstem was performed with the BigBrain database.

RESULTS

Thirteen entry zones were reported and assessed for their safety, including the anterior mesencephalic zone, lateral mesencephalic sulcus, interpeduncular zone, intercollicular region, supratrigeminal zone, peritrigeminal zone, lateral pontine zone, median sulcus, infracollicular zone, supracollicular zone, olivary zone, lateral medullary zone, and anterolateral sulcus. The microanatomy, safety, and approaches are discussed.

CONCLUSIONS

PLI and 11.7-T MRI data show that a neurosurgeon possibly does not need to consider the microanatomical structures that would not be visible on conventional MRI and tractography when entering the mentioned safe entry zones. However, the detailed anatomical images may help neurosurgeons increase their understanding of the internal architecture of the human brainstem, which in turn could lead to safer neurosurgical intervention.

The Current State of Radiotherapy for Pediatric Brain Tumors: An Overview of Post-Radiotherapy Neurocognitive Decline and Outcomes

Tumors of the central nervous system are the most common solid malignancies diagnosed in children. While common, they are also found to have some of the lowest survival rates of all malignancies. Treatment of childhood brain tumors often consists of operative gross total resection with adjuvant chemotherapy or radiotherapy. The current body of literature is largely inconclusive regarding the overall benefit of adjuvant chemo- or radiotherapy. However, it is known that both are associated with conditions that lower the quality of life in children who undergo those treatments. Chemotherapy is often associated with nausea, emesis, significant fatigue, immunosuppression, and alopecia. While radiotherapy can be effective for achieving local control, it is associated with late effects such as endocrine dysfunction, secondary malignancy, and neurocognitive decline. Advancements in radiotherapy grant both an increase in lifetime survival and an increased lifetime for survivors to contend with these late effects. In this review, the authors examined all the published literature, analyzing the results of clinical trials, case series, and technical notes on patients undergoing radiotherapy for the treatment of tumors of the central nervous system with a focus on neurocognitive decline and survival outcomes.

Combined Treatment With Radiotherapy and Immunotherapy for Isocitrate Dehydrogenase Mutant Brainstem Glioma in Adult: A Case Report

Brainstem gliomas are not common in adults, and the treatment strategies and their outcomes are limited. Immunotherapy is emerging as a promising new modality for the treatment of these gliomas. Here, we report the first case of brainstem glioma treated with a combination of radiotherapy and autologous formalin-fixed tumor vaccine (AFTV). A 32-year-old man presented with left facial numbness and right hemiparesis, and was referred to our department. MRI and open biopsy indicated brainstem glioma, and he was specifically diagnosed with isocitrate dehydrogenase 1-mutant diffuse astrocytoma of WHO grade II. He was treated with stereotactic radiotherapy followed by AFTV three months later. MRI conducted at 42 months after the combination therapy showed a 91% decrease in tumor volume, and the regression was maintained for 5 years. Thus, combination treatment with radiotherapy and immunotherapy may prove to be a promising alternative for the treatment of brainstem glioma.

Adult brainstem gliomas

Brainstem gliomas in adults are a rare and heterogeneous group of brain tumors that vary with regard to underlying pathology, radiographic appearance, clinical course and prognosis. Diffuse intrinsic pontine gliomas represent the most common subtype. Although still considered aggressive and most often lethal, these brain tumors are associated with a more insidious clinical course and more favorable prognosis compared to the highly aggressive form in children. Treatment options for patients with brainstem gliomas still are limited and insufficiently studied. A better understanding of the pathobiology of these tumors will be crucial for the development of more specific and effective therapies. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2799-2809. © 2016 American Cancer Society.

High-Grade Glioma of the Ventrolateral Medulla in an Adult: Case Presentation and Discussion of Surgical Considerations

Background. High-grade gliomas of the brainstem are rare in adults and are particularly rare in the anterolateral medulla. We describe an illustrative case and discuss the diagnostic and treatment issues associated with a tumor in this location, including differential diagnosis, anatomical considerations for options for surgical management, multimodality treatment, and prognosis. Case Description. A 69-year-old woman presented with a 3-week history of progressive right lower extremity weakness. She underwent an open biopsy via a far lateral approach with partial condylectomy, which revealed a glioblastoma. Concurrent temozolomide and radiation were completed; however, she elected to stop her chemotherapy after 5.5 weeks of treatment. She succumbed to her disease 11 months after diagnosis. Conclusions. Biopsy can be performed relatively safely to provide definitive diagnosis to guide treatment, but long-term prognosis is poor.

Principles of radiation therapy

Although resection remains the mainstay in the treatment of gliomas, microscopically complete resection of most central nervous system tumors remains challenging, and is, in fact, rarely accomplished. Considering their invasive nature, gross total resections to clearly negative margins often do or would require removal or transection of functional brain, with likely serious neurologic deficits. Consequently, radiotherapy has emerged as an indispensable component of therapy. It is delivered primarily by external-beam radiotherapy or brachytherapy techniques. Herein, we present the biologic principles, techniques, and applications of radiotherapy in glioma treatment today.

Clinical management and outcome of histologically verified adult brainstem gliomas in Switzerland: a retrospective analysis of 21 patients

Because of low incidence, mixed study populations and paucity of clinical and histological data, the management of adult brainstem gliomas (BSGs) remains non-standardized. We here describe characteristics, treatment and outcome of patients with exclusively histologically confirmed adult BSGs. A retrospective chart review of adults (age >18 years) was conducted. BSG was defined as a glial tumor located in the midbrain, pons or medulla. Characteristics, management and outcome were analyzed. Twenty one patients (17 males; median age 41 years) were diagnosed between 2004 and 2012 by biopsy (n = 15), partial (n = 4) or complete resection (n = 2). Diagnoses were glioblastoma (WHO grade IV, n = 6), anaplastic astrocytoma (WHO grade III, n = 7), diffuse astrocytoma (WHO grade II, n = 6) and pilocytic astrocytoma (WHO grade I, n = 2). Diffuse gliomas were mainly located in the pons and frequently showed MRI contrast enhancement. Endophytic growth was common (16 vs. 5). Postoperative therapy in low-grade (WHO grade I/II) and high-grade gliomas (WHO grade III/IV) consisted of radiotherapy alone (three in each group), radiochemotherapy (2 vs. 6), chemotherapy alone (0 vs. 2) or no postoperative therapy (3 vs. 1). Median PFS (24.1 vs. 5.8 months; log-rank, p = 0.009) and mOS (30.5 vs. 11.5 months; log-rank, p = 0.028) was significantly better in WHO grade II than in WHO grade III/IV tumors. Second-line therapy considerably varied. Histologically verification of adult BSGs is feasible and has an impact on postoperative treatment. Low-grade gliomas can simple be followed or treated with radiotherapy alone. Radiochemotherapy with temozolomide can safely be prescribed for high-grade gliomas without additional CNS toxicities.

Interstitial brachytherapy with iodine-125 seeds for low grade brain stem gliomas in adults: diagnostic and therapeutic intervention in a one-step procedure

PURPOSE

To report on iodine-125 (I125) interstitial irradiation in the treatment of low grade brain stem gliomas in adults.

PATIENTS AND METHODS

Ten patients with well-circumscribed lesions of the brainstem and histological confirmation of low grade glioma treated with stereotactically implanted I-125 seed in our department between 1995 and 2012 were retrospectively analyzed.

RESULTS

In 9 patients the lesion was treated with one I-125 seed and in one patient, 2 spatial separated lesions were implanted, therefore a total of 11 I-125 seeds were implanted. The mean volume of the 11 lesions was 2.76 ml (range: 0.5-7.2 ml), mean activity of the seeds was 6.23 mCi (range: 1.5-11.1 mCi), mean duration of irradiation was 28.5 days (range: 21-41 days) and mean effective dose rate was 9.16 cGy/h (range: 6.2-12 cGy/h). The 30 days perioperative morbidity and mortality rate was 0%. Median follow up was 72.5 month (range 5-168 months). Six of ten patients were free of progression until last follow up.

CONCLUSION

In our experience at the University Clinic in Freiburg Germany, interstitial radiosurgery based on MRI is a safe and effective method to diagnose and treat low grade gliomas of the brain stem. Furthermore randomized studies are needed to confirm the therapeutic impact of this method in comparison to external beam radiation of brain stem gliomas.

Differences in clinical results after LINAC-based single-dose radiosurgery versus fractionated stereotactic radiotherapy for patients with vestibular schwannomas

PURPOSE

To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a median total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose.

RESULTS

FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of < or =13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (< or =13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of < or =13 Gy, cranial nerve toxicity was comparable to that of the FSRT group.

CONCLUSIONS

FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of < or =13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.

[Advances in radio-oncology. From precision radiotherapy with photons to ion therapy with protons and carbon ions]

Modern techniques in radiation oncology, such as fractionated stereotactic radiotherapy (FSRT), stereotactic radiosurgery (SRS) or intensity modulated radiotherapy (IMRT) allow the application of high local doses to defined treatment volumes, while normal structures in close vicinity can be spared; high local control rates can be achieved, while treatment-related toxicity can be minimized. Innovative Hi-Art tomotherapy systems offer an alternative, combining a 6 MV photon accelerator with a CT scanner. Ion beams, such as protons and carbon ions, have been shown to be beneficial for distinct tumor entities. Both offer a characteristic physical dose distribution with an inverse dose profile contributing to beneficial dose conformality. Carbon ions also offer the advantage of increased relative biological effectiveness. For certain tumor types, a significant increase in local control and survival rates could be obtained with carbon ions.

Fractionated stereotactic radiotherapy for pituitary adenomas following microsurgical resection: safety and efficacy

The treatment of pituitary adenomas following medical management has historically involved surgical excision or stereotactic radiosurgery, with the two modalities often utilized collectively. However, there have been only a limited number of reports on the use of fractionated stereotactic radiotherapy (FSRT) for the treatment of pituitary adenomas. To enhance the existing knowledge regarding the safety and efficacy of this treatment modality, we describe our initial experience with FSRT for residual pituitary adenomas following microsurgical resection. From 1999 to 2005, 14 patients (7F, 7M) with residual pituitary adenomas (7 nonsecretory, 2 growth hormone secreting, 2 prolactin secreting, 2 thyrotropin secreting, 1 adrenocorticotropic hormone secreting) underwent FSRT. All patients were planned using the Radionics X-Knife 3D planning system, and received a median dose of 50.4 Gy in daily 1.8 Gy fractions administered to the 90% prescription isodose line. Treatments were delivered stereotactically using a dedicated Varian 6/100 linear accelerator, with immobilization achieved with the Gill-Thomas-Cosman relocatable head frame. Mean tumor size was 3.6 cm (median, 3.2 cm), and mean patient age was 44.6 years (median, 47 years). The mean dosages to the optic chiasm and brainstem were 0.159 and 0.040 Gy (median, 0.163 and 0.031 Gy) per fraction. All patients were evaluated with visual field testing and pre- and postgadolinium-enhanced magnetic resonance imaging at a minimum of one year follow-up (median, 22.5 months; mean, 27.8 months). Following FSRT, local control (defined as absence of tumor progression) was achieved in all fourteen patients. Three patients developed hypopituitarism (average, 30 months after treatment), with no patient experiencing visual changes or acute complications following FSRT. These results demonstrate the efficacy and safety of FSRT for achieving long-term local tumor control for pituitary adenomas, further validating this technique as an appropriate treatment modality for residual adenomas following microsurgery.

Intensity Modulated Radiotherapy (IMRT) and Fractionated Stereotactic Radiotherapy (FSRT) for children with head-and-neck-rhabdomyosarcoma

Background

The present study evaluates the outcome of 19 children with rhabdomyosarcoma of the head-and-neck region treated with Intensity Modulated Radiotherapy (IMRT) or Fractionated Stereotactic Radiotherapy (FSRT) between August 1995 and November 2005.

Methods

We treated 19 children with head-and-neck rhabdomyosarcoma with FSRT (n = 14) or IMRT (n = 5) as a part of multimodal therapy. Median age at the time of radiation therapy was 5 years (range 2–15 years). All children received systemic chemotherapy according to the German Soft Tissue Sarcoma Study protocols.

Median size of treatment volume for RT was 93,4 ml. We applied a median total dose of 45 Gy (range 32 Gy – 54 Gy) using a median fractionation of 5 × 1,8 Gy/week (range 1,6 Gy – 1,8 Gy).

The median time interval between primary diagnosis and radiation therapy was 5 months (range 3–9 months).

Results

After RT, the 3- and 5-year survival rate was 94%. The 3- and 5-year actuarial local control rate after RT was 89%.

The actuarial freedom of distant metastases rate at 3- and 5-years was 89% for all patients.

Radiotherapy was well tolerated in all children and could be completed without interruptions > 4 days. No toxicities >CTC grade 2 were observed. The median follow-up time after RT was 17 months.

Conclusion

IMRT and FSRT lead to excellent outcome in children with head-and-neck RMS with a low incidence of treatment-related side effects.

Achievement of long-term local control in patients with craniopharyngiomas using high precision stereotactic radiotherapy

BACKGROUND

The long-term outcome in patients with craniopharyngiomas treated with fractionated stereotactic radiotherapy (FSRT) was evaluated.

METHODS

A total of 40 patients with craniopharyngiomas were treated between May 1989 and July 2006 with FSRT. Most patients were treated for tumor progression after surgery. A median target dose of 52.2 grays (Gy) (range, 50.4-56 Gy) was applied in a median conventional fractionation of 5 x 1.8 Gy per week. Follow-up examinations included thorough clinical assessment as well as contrast-enhanced magnetic resonance imaging scans.

RESULTS

After a median follow-up of 98 months (range, 3-326 months), local control was 100% at both 5 years and 10 years. Overall survival rates at 5 years and 10 years were 97% and 89%, respectively. A complete response was observed in 4 patients and partial responses were noted in 25 patients. Eleven patients presented with stable disease during follow-up. Acute toxicity was mild in all patients. Long-term toxicity included enlargement of cysts requiring drainage 3 months after FSRT. No visual impairment, radionecrosis, or development of secondary malignancies were observed.

CONCLUSIONS

The long-term outcome of FSRT for craniopharyngiomas is excellent with regard to local control as well as treatment-related side effects.

State of the art chemotherapeutic management of pediatric brain tumors

CNS tumors are the most common solid tumor of childhood. This article will review current treatments for pediatric brain tumors; low-grade gliomas, high-grade gliomas, medulloblastomas and ependymomas. It will also highlight the treatments that are used for brain tumors in very young children and in children with recurrent brain tumors. The management of recurrent pediatric brain tumors unresponsive to standard therapy will be discussed. The agents used in this setting are mainly biological modifiers, which attempt to provide molecularly targeted therapy. Future directions of therapy for pediatric brain tumors are described. Future treatment paradigms will need to consider examining the use of multiple biological modifiers. Similarly, these agents will need to be examined in combination with cytotoxic chemotherapy. Finally, the future direction of pediatric neuro-oncology and the focus of the field as it battles pediatric brain tumors is discussed.

Treatment of primary glioblastoma multiforme with cetuximab, radiotherapy and temozolomide (GERT)--phase I/II trial: study protocol

Background

The implementation of combined radiochemotherapy (RCHT) with temozolomide (TMZ) has lead to a significant increase in overall survival times in patients with Glioblastoma multiforme (GBM), however, outcome still remains unsatisfactory.

The majority of GBMs show an overexpression and/or amplification of the epidermal growth factor receptor (EGFR). Therefore, addition of EGFR-inhibition with cetuximab to the current standard treatment approach with radiotherapy and TMZ seems promising.

Methods/design

GERT is a one-armed single-center phase I/II trial. In a first step, dose-escalation of TMZ from 50 mg/m² to 75 mg/m² together with radiotherapy and cetuximab will be performed. Should safety be proven, the phase II trial will be initiated with the standard dose of 75 mg/m² of TMZ. Cetuximab will be applied in the standard application dose of 400 mg/m² in week 1, thereafter at a dose of 250 mg/m² weekly. A total of 46 patients will be included into this phase I/II trial.

Primary endpoints are feasibility and toxicity, secondary endpoints are overall and progression-free survival. An interim analysis will be performed after inclusion of 15 patients into the main study. Patients' enrolment will be performed over a period of 2 years. The observation time will end 2 years after inclusion of the last patient.

Discussion

The goal of this study is to evaluate the safety and efficacy of combined RCHT-immunotherapy with TMZ and cetuximab as first-line treatment for patients with primary GBM.

Diffuse brainstem glioma in children: critical review of clinical trials

Diffuse intrinsic brainstem gliomas constitute 15-20% of all CNS tumours in children, and are the main cause of death in children with brain tumours. Many clinical trials have been done over the past three decades, but survival has remained static. More than 90% of children die within 2 years of diagnosis, and conventional fractionated radiation remains the standard treatment. However, median survival differs substantially between clinical trials, suggesting a survival benefit with some strategies. We appraised the consistency between protocols in terms of eligibility criteria, definition and assessment of response and progression, statistical design, and endpoints. Study designs varied substantially, which could explain the differences in outcome, and no treatment has shown a benefit over conventional radiotherapy. However, consistency between protocols (eg, eligibility criteria and outcome measures) is important to measure the progress in management of diffuse pontine gliomas.

Follow-up gliomas after radiotherapy: 1H MR spectroscopic imaging for increasing diagnostic accuracy

We evaluated the value of magnetic resonance imaging (MRI) and the additional benefit of proton MR spectroscopic imaging (1H SI) in patients with a new suspicious lesion after fractionated stereotactic radiotherapy (FSRT) of a glioma. Thirty-four patients with histologically proven astrocytoma WHO II-IV after treatment by FSRT and a new suspect lesion in the follow-up were included in this study. Data were analysed by three independent radiologists with different experience in 1H SI: Data were verified by clinical follow-up (PT, progressive tumour; nPT, non-progressive tumour) and a kappa analysis was performed. Sensitivity and specificity of T1 weighted (w) and T2w MRI was compared (imaging at radiotherapy and follow-up) using further follow-up controls as gold standard and the additional benefit of 1H SI (imaging at follow-up) was calculated. Mean interval between last irradiation and detection of a suspicious lesion was 37 +/- 32 months. Time to clinical evaluation was 13 +/- 8 months. Interobserver agreement was significantly high in all analyses (kappa always >0.8, P < 0.05). T2w imaging proved to be superior to contrast enhanced T1w imaging in sensitivity (87.5 vs 81.25%) and specificity (85.7 vs 57.1%). Solitary 1H SI had similar results as T2w (sensitivity 87.5%, specificity 71.4%). Taking all techniques into account, all PT were correctly diagnosed. Radiologists' experience had no significant influence on correct interpretation of a suspicious lesion. We conclude that 1H SI is helpful in characterising new suspicious lesions in irradiated gliomas, particularly if pre-MRI is not available for evaluating follow-up.

Management of acoustic neuromas with fractionated stereotactic radiotherapy (FSRT): Long-term results in 106 patients treated in a single institution

PURPOSE

To assess the long-term outcome and toxicity of fractionated stereotactic radiotherapy for acoustic neuromas in 106 patients treated in a single institution.

PATIENTS AND METHODS

Between October 1989 and January 2004, fractionated stereotactic radiotherapy (FSRT) was performed in 106 patients with acoustic neuroma (AN). The median total dose applied was 57.6 Gy in median single fractions of 1.8 Gy in five fractions per week. The median irradiated tumor volume was 3.9 mL (range, 2.7-30.7 mL). The median follow-up time was 48.5 months (range, 3-172 months).

RESULTS

Fractionated stereotactic radiotherapy was well tolerated in all patients. Actuarial local tumor control rates at 3- and 5- years after FSRT were 94.3% and 93%, respectively. Actuarial useful hearing preservation was 94% at 5 years. The presence of neurofibromatosis (NF-2) significantly adversely influenced hearing preservation in patients that presented with useful hearing at the initiation of RT (p = 0.00062). Actuarial hearing preservation without the diagnosis of NF-2 was 98%. In cases with NF-2, the hearing preservation rate was 64%. Cranial nerve toxicity other than hearing impairment was rare. The rate of radiation induced toxicity to the trigeminal and facial nerve was 3.4% and 2.3%, respectively.

CONCLUSION

Fractionated stereotactic radiotherapy is safe and efficacious for the treatment of AN, with mild toxicity with regard to hearing loss and cranial nerve function. FSRT might be considered as an equieffective treatment modality compared to neurosurgery and therefore represents an interesting alternative therapy for patients with AN.

Fractionated stereotactic radiation therapy in the management of primary oligodendroglioma and oligoastrocytoma

PURPOSE

To retrospectively analyze the outcomes and benefits from radiation therapy (RT) as a component of multimodal treatment for oligodendroglioma and oligoastrocytoma, assessing local control and survival rates and evaluating prognostic factors.

METHODS AND MATERIALS

We retrospectively reviewed 56 adult patients with supratentorial oligodendroglioma or oligoastrocytoma treated at our institution from January 1990 to December 2003 with fractionated stereotactic RT (FSRT).

RESULTS

Fractionated stereotactic RT was well tolerated in all patients, without side effects. Median survival and progression-free survival calculated from the initiation of radiotherapy were 48 months (range, 2-133 months) and 38 months (range, 2-132 months), respectively. Progression-free survival rates after radiation were 89% at 1 year and 52% at 5 years. Of 26 recurrences, 92% developed in field. With regard to histology, overall survival rates in the World Health Organization (WHO) Grade II group were 89% and 74% at 5 and 10 years, respectively. In patients with WHO Grade III tumors, overall survival rates at 5 and 10 years were 69% and 46%, respectively. No prognosticators could be identified for median survival and progression-free survival after radiotherapy. Median overall survival calculated from primary diagnosis was 77.5 months (range, 3-214 months). The Cox regression multivariate analysis for age and neurologic symptoms showed a significance of p = 0.003 for age and p = 0.037 for the presence of neurologic symptoms on overall survival since primary diagnosis.

CONCLUSIONS

Commonly, conventional conformal RT is applied in the treatment of brain tumors. In FSRT, the tumor volume can be irradiated with high doses, sparing volume of normal brain tissue. Our data are in accordance with survival times found in the literature. Ninety-two percent of all recurrences occurred within the defined target volume, confirming that reduction of the RT portals by the use of FSRT does not lead to an increased rate of recurrences at the field border or out of field. Fractionated stereotactic RT can therefore be implemented as an effective and safe modality in the therapy of primary oligodendroglioma and oligoastrocytoma.

Integration of surgery with fractionated stereotactic radiotherapy for treatment of nonfunctioning pituitary macroadenomas

OBJECTIVE

To evaluate the efficacy of fractionated stereotactic radiotherapy (FSRT) after surgery in the management of residual or recurrent nonfunctioning pituitary adenomas with respect to tumor control and the development of complications.

METHODS AND MATERIALS

The clinical records of patients with nonfunctioning pituitary adenomas who underwent FSRT were retrospectively analyzed. For newly diagnosed tumors, transsphenoidal surgery was performed, and, if residual tumor was identified at 3 months, FSRT was performed. If significant tumor volume persisted, transcranial surgery was performed before FSRT. We originally initiated FSRT with 2-Gy fractions to 46 Gy. We escalated the dose to 50.4 Gy thereafter. As a final modification, we dropped the daily dose to 1.8-Gy fractions delivered within 6 weeks. High-dose conformality and homogeneity was achieved with arc beam shaping and differential beam weighting. The radiographic, endocrinologic, and visual outcomes after FSRT were evaluated.

RESULTS

The 68 patients included 36 males and 32 females with an age range of 15-81 years. The median follow-up was 30 months (range, 2-82 months), and the median tumor volume was 6.2 cm(3). Of the 68 patients, 20 were treated to 46 Gy and 48 to 50-52.2 Gy. Most were treated to 50.4 Gy. Eleven patients had recurrent tumors, 54 had residual tumors, and no surgery was performed in 3 patients before FSRT. We noted no radiation-induced acute or late toxicities, except for radiation-induced optic neuropathy in 2 patients. At latest follow-up, the tumor had decreased in size in 26 patients and remained stable in 41 of the 42 remaining patients. Of the 68 patients, 4 (6%) developed hypopituitarism at 6, 11, 12, and 17 months after FSRT. Reviewing available serial Humphrey visual fields, visual fields were objectively improved in 28 patients, and remained stable in 24 patients, and worsened in 2 patients.

CONCLUSION

The findings of this analysis support the use of surgery followed by FSRT as a safe, effective, and integrated treatment for nonfunctioning pituitary adenomas. Additional follow-up is needed to document the long-term tumor control rates, preservation rates for vision and pituitary function, and neurocognitive outcomes.

Low-grade gliomas treated by fractionated gamma knife surgery

OBJECT

The authors sought to evaluate local tumor control, complications, and progression-free survival in patients harboring low-grade gliomas who were treated with Leksell gamma knife surgery (GKS).

METHODS

During a 6-year period 70 patients were treated for verified low-grade gliomas (Grade I or II) by GKS. Statistical analysis was based on 68 patients; two patients were lost to follow up. The median patient age was 17 years. The median target volume was 4200 mm.3 The median prescription dose was 25 Gy. The median number of fractions was five. Ninety-five percent of patients were treated in five daily fractions. Partial or complete tumor regression was achieved in 83% of patients with a median time to response of 18 months. There was moderate acute or late toxicity in not more than 5% of patients. In this series the progression-free survival was 92% at 3 years and 88% at 5 years.

CONCLUSIONS

Relatively high local tumor control with minimal complications was achieved.

Recurrent low-grade gliomas: the role of fractionated stereotactic re-irradiation

PURPOSE

To assess the effectiveness of re-irradiation in recurrent low-grade gliomas (LGG).

PATIENTS AND METHODS

Sixty-three patients were treated with fractionated stereotactic re-irradiation in the case of recurrent gliomas. At primary diagnosis of the tumor, the histology was grade II astrocytoma, oligodendroglioma or oligoastrocytoma. Fifty-two (82.5%) recurrences were in-field, three (4.8%) were localized at the field border, and eight (12.7%) tumors were localized completely out-field of the former RT field, respectively. Using three to four irregular non-coplanar fields formed with a multi-leaf-collimator, we applied a median total dose of 36 Gy (range 15-62 Gy)with a weekly fractionation of 5 x 2 Gy/week depending on the size and the location of the lesion. No concomitant chemotherapy was applied.

RESULTS

Radiation was well tolerated by all patients. No severe side effects occurred. Median overall survival was 111 months (range 12-240 months). Extent of neurosurgical resection significantly influenced overall survival (P = 0.02). Median interval between the first radiation therapy and re-irradiation was 50 months (range 5-204 months). From the time point of re-irradiation, median survival was 23 months. Median progression-free survival from the time point of re-irradiation was 12 months (range 2-63 months). No prognosticators could be identified for survival from re-irradiation and progression free survival.

CONCLUSION

Our retrospective data suggest that stereotactically guided fractionated re-irradiation in recurrent glioma represents an effective treatment option with good results and few complications. However, further investigation is warranted to consolidate these results and to combine radiation with chemotherapy in the case of recurrent LGG.

Gliomas del tronco encefálico

Brainstem gliomas have been increasingly understood in the last two decades and they are nowadays regarded as an heterogeneous group of tumors with tendency towards the pediatric age, where they account for 10-20% of brain neoplasms. Besides the well known diffuse tumor, several subtypes, with a different biological behaviour, amenable to surgical resection and better prognosis, have been identified, giving rise to many classifications and terms. In the other way, attention has been recently paid to adult brainstem gliomas in contrast to pediatric tumors. Based on a review of the literature, we describe the different subtypes of brainstem gliomas, with particular interest on therapeutic approaches and differences between pediatric and adult tumors, employing iconography from our series.

Gross total surgical removal of malignant glioma from the medulla oblongata: report of two adult cases with reference to surgical anatomy

Surgery was performed on the medulla oblongata of two adult patients with malignant glioma. Gross total resection of the tumors, located laterally or medially in the upper half of the medulla respectively, was achieved. The patient with the medially located tumor experienced significant postoperative neurological deterioration including sleep apnea. The other patient with the laterally located tumor showed symptomatic improvement without respiratory complications. The patient with an anaplastic astrocytoma survived approximately 4 years and the patient with a glioblastoma multiforme approximately 2 years. Although the upper half of the medulla is more critical than the lower half, a lateral approach to the upper half of the medulla appears to be relatively safer than a medial approach. Some cases of focal malignant gliomas in the medulla may be amenable to gross total resection in order to achieve improved outcome. Surgery can be undertaken when a tumor is unilateral and its margin appears relatively clear on magnetic resonance images.

The role of MRI in patients with astrocytoma WHO II treated with fractionated stereotactic radiotherapy

Aim of this study was to evaluate the role of pre-therapeutic and follow-up MRI in the clinical treatment and outcome in patients with astrocytoma WHO grade II after fractionated stereotactic radiation therapy (FSRT). One hundred thirty-nine patients with histologically proven astrocytoma WHO grade II were treated with FSRT and retrospectively evaluated. All patients had follow-up MRI studies (Gd-DTPA-enhanced T1- and T2-weighted MR images). Progression-free survival (PFS) and overall survival (OS) rates were calculated using the Kaplan-Meier method. Multivariate analysis was performed on five potential MRI related prognosticators. Median follow-up was 3.8 years. Positive contrast enhancement (CM+) prior to FSRT proved to be a significant prognosticator for PFS and OS (p<0.01). Pre-therapeutic oedema on T2-weighted images and multifocality of contrast medium (CM) enhancement did not prove to be significant prognosticators. Also, diameter and volume of CM enhancement showed no significance on clinical outcome. Negative contrast enhancing (CM-) patients developing a de novo CM enhancement during follow-up showed a significantly worse clinical outcome compared with generally CM- patients (p<0.05). Pre-therapeutic CM enhancement and the development of CM-enhancing areas during follow-up are negative prognosticators for PFS and OS. They must be interpreted as signs of secondary malignity.

Fractionated stereotactic radiotherapy in low-grade astrocytomas: Long-term outcome and prognostic factors

PURPOSE

To evaluate outcome after fractionated stereotactic radiotherapy (RT) of patients with World Health Organization Grade 2 astrocytoma in terms of progression-free survival, overall survival, toxicity, quality of life, and prognostic factors.

METHODS AND MATERIALS

Between 1984 and 2000, 143 patients with histologically proven Grade 2 astrocytoma were treated with fractionated stereotactic RT at our institution. The evaluation of the quality of life and toxicity was based on neurologic examinations and the Karnofsky performance score. Univariate analysis was performed on seven potential prognosticators and multivariate analysis on four prognosticators.

RESULTS

The median follow-up was 44 months. The actuarial overall survival and progression-free survival was 58% and 39% at 5 years, respectively. Out-of-field recurrences occurred in 1 patient (1.2%). We did not observe a dose-response relationship. Overall survival and progression-free survival were significantly correlated with the absence of contrast media enhancement before RT (p <0.01). Toxicity was mild and included severe side effects of European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group Grade 3 in only 4 patients (2.8%). The Karnofsky performance score improved in most patients.

CONCLUSION

Fractionated stereotactic RT is effective and has low toxicity in the treatment of Grade 2 gliomas. The rate of field border recurrences was not increased compared with after conventional RT. Exceeding the tumor dose did not improve the tumor control rate but did enhance toxicity. Pretherapeutic contrast media enhancement should be interpreted as a sign of higher grade tumor elements.

Fractionated stereotactic radiotherapy for craniopharyngiomas

PURPOSE

To investigate outcome and toxicity after fractionated stereotactic radiation therapy (FSRT) in patients with craniopharyngiomas.

METHODS AND MATERIALS

Twenty-six patients with craniopharyngiomas were treated with FSRT between May 1989 and February 2001. Median age was 33.5 years (range: 5-57 years). Nine patients received FSRT after surgery as primary treatment, and 17 patients were irradiated for recurrent tumor or progressive growth after initial surgery. Median target dose was 52.2 Gy (range: 50.0-57.6 Gy) with conventional fractionation. Follow-up included MRI and neurologic, ophthalmologic, and endocrinologic examinations.

RESULTS

The median follow-up was 43 months (range: 7-143 months). The actuarial local control rate and actuarial overall survival rates were 100% and 100%, respectively, at 5 years and 100% and 83%, respectively, at 10 years. Four patients showed complete response, 14 patients showed partial response, and 8 patients remained stable. In 5 patients, vision improved after radiation therapy. Acute toxicity was mild. One patient required cyst drainage 3 months after radiotherapy. Late toxicity after radiotherapy included impairment of hormone function in 3 out of 18 patients at risk. We did not observe any vision impairment, radionecrosis, or secondary malignancies.

CONCLUSIONS

FSRT is effective and safe in the treatment of cystic craniopharyngiomas. Toxicity is extremely low using this conformal technique.

Brain stem gliomas

Brainstem gliomas are now regarded as a heterogeneous group of tumors that can be distinguished by age of onset, clinical and radiological presentation and biological behavior. This paper will focus on each subtype of tumor, in children and in adults, and on recent advances in diagnostic criteria and therapeutic options.

Postoperative radiotherapy of astrocytomas

Astrocytomas account for the majority of primary brain tumors. Low-grade tumors are slowly growing tumors with relatively long overall survival. However, a high percentage of these tumors transform to more malignant, high-grade tumors. High-grade gliomas (anaplastic astrocytomas and glioblastoma multiforme) have a poor prognosis. Treatment options are capable of prolonging the natural history of the disease, but the long-term survival is poor. This review discusses the different postoperative treatment options and the prognostic factors in low- and high-grade astrocytomas.