Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Radiosurgical techniques for the treatment of brain neoplasms: A short review

Radiotherapy has long been used as an adjunct to neurosurgery for the treatment of malignant and benign intracranial tumors and other intracranial lesions. Intracranial tumors can be irradiated in three different ways: I) fractional radiotherapy, II) stereotactic radiotherapy and III) stereotactic radiosurgery. The third is most often by means of a gamma knife or a specially designed linear accelerator. Additionally, radiosurgery is increasingly used in combination with systemic therapy to treat metastases.

Clinical Outcomes of Stereotactic Body Radiotherapy in Oligometastatic Gynecological Cancer

OBJECTIVE

The objective of this study was to assess the role of stereotactic body radiotherapy (SBRT) in the treatment of distantly recurrent, oligometastatic gynecological cancer.

METHODS

The hospital records of 45 patients with F-fluorodeoxyglucose (F-FDG) positron emission tomography positive, distantly recurrent, oligometastatic gynecological cancer were reviewed. All these patients had a number of target lesions less than 5, with largest diameter less than 6 cm. The treatment was delivered with a TrueBeam LINAC and RapidArc technique, using 10 or 6 MV FFF beams. A total of 70 lesions were treated, and lymph nodes represented the most common site of metastases, followed by lung, liver, and soft tissues. Twenty lesions were treated with one single fraction of 24 Gy and 5 lesions received 27 Gy delivered in 3 fractions, depending on the ability to fulfill adequate target coverage and safe dose/volume constraints for the organ at risk with either regimen.

RESULTS

Positron emission tomography scan 3 months after SBRT showed a complete response (CR) in 45 lesions (64.3%), a partial response in 14 (20.0%), a stable disease in 5 (7.1%), and a progressive disease in 6 (8.6%). No lesions in CR after SBRT subsequently progressed. Overall acute toxicity occurred in 13 (28.9%) patients. The most common grade 1 to 2 adverse event was pain (n = 9, 20.0%), followed by nausea and vomiting (n = 5, 11.1%). No grade 3 to 4 acute toxicities occurred, and no late toxicities were observed. Patients who failed to achieve a CR had a 2.37-fold higher risk of progression and a 3.60-fold higher risk of death compared with complete responders (P = 0.04 and P = 0.03, respectively).

CONCLUSIONS

Stereotactic body radiotherapy offers an effective and safe approach for selected cases of oligometastatic gynecological cancer.

The Basic Steps of Evolution of Brain Surgery

OBJECTIVE AND CONCLUSION

Neurosurgery is probably the most constantly developing specialty of all times. Its dimension is enormous and its history, Ancient. The evolution of neurosurgery from the Mayan and Egyptian periods to the Renaissance and the 21st century was the result of many physicians and patients whose experiences lead to the revolution of modernization. Today, the field of neurosurgery is continuously expanding, aiming to introduce knowledge and technologies that could provide a new futuristic wave of medicine.

METHODS

Given this background, our team selected relevant data from Medline published between 1936 and 2017.

RESULTS

We included 91 articles on this topic, all of them providing enough information about the revolution and progress of brain surgery through the centuries as well as its potential expansion in the future.

Treatment of orbital solitary fibrous tumour with gamma knife radiosurgery and systematic review of literature

Solitary fibrous tumours (SFTs) are relatively rare tumours that were originally thought to arise from the pleura but have thereafter been demonstrated as occurring anywhere in the body. These tumours are generally considered benign but have frequently been noted for recurrence and local invasion. Furthermore, their indolence is controversial due to increasing evidence implicating the existence of a spectrum that includes hemangiopericytoma (HPC). Stereotactic radiosurgery (SRS) has been well characterised in the treatment of benign, malignant and vascular conditions, and it appears to be a reasonable option as adjuvant or recurrent treatment for intracranial SFTs. We present in this case the first complete description of an SFT of the orbit treated by SRS as well as a systematic review of available English literature for intracranial SFTs treated by SRS. We report effective local tumour control in our case and conclude that SRS is a reasonable treatment option for recurrent SFT.

Stereotactic radiosurgery of glomus jugulare tumors: current concepts, recent advances and future perspectives

Stereotactic radiosurgery (SRS), a very highly focused form of therapeutic irradiation, has been widely recognized as a viable treatment option in the management of intracranial pathologies including benign tumors, malign tumors, vascular malformations and functional disorders. The applications of SRS are continuously expanding thanks to the ever-increasing advances and corresponding improvements in neuroimaging, radiation treatment techniques, equipment, treatment planning and delivery systems. In the context of glomus jugulare tumors (GJT), SRS is being more increasingly used both as the upfront management modality or as a complementary or salvage treatment option. As its safety and efficacy is being evident with compiling data from studies with longer follow-up durations, SRS appears to take the lead in the management of most patients with GJT. Herein, we address current concepts, recent advances and future perspectives in SRS of GJT in light of the literature.

Metastasis of an occult pulmonary carcinoma into meningioma: a case report

Tumour-to-tumour metastasis is an infrequent pathological phenomenon. Meningioma is the most common intracranial tumour where metastatic deposits may be found, the majority of which arise from breast and lung cancers. We describe an unusual case of occult pulmonary carcinoma metastasis into the intracranial meningioma. A 77-year old lady presented with acutely deteriorating hemiparesis. Her previous medical history was unremarkable. Radiological imaging revealed an expansive lesion, classified as meningioma, which was located parasagittally in the right premotor area. A well-capsulated tumour attached to the dura was removed surgically. The pathological examination demonstrated a mixture of angiomatous meningioma and pulmonary adenocarcinoma. Possible explanations for the development of a composite tumour and pathophysiology are described.

Stereotactic radiosurgery of brainstem cavernous malformations: a systematic review and meta-analysis

OBJECT

Over the last two decades, stereotactic radiosurgery (SRS) has arisen as a promising approach in the management of brainstem cavernous malformations (CMs). In the present study, the authors report a systematic review and meta-analysis of the available published data regarding the radiosurgical management of brainstem CMs.

METHODS

To identify eligible studies, systematic searches for brainstem CMs treated with SRS were conducted in major scientific publication databases. The search yielded 5 studies, which were included in the meta-analysis. Data from 178 patients with brainstem CMs were extracted. Hemorrhage rates before and after SRS were calculated, a meta-analysis was performed, and the risk ratio (RR) was determined.

RESULTS

Four studies showed a statically significant reduction in the annual hemorrhage rate after SRS. The overall RR was 0.161 (95% CI 0.052-0.493; p = 0.001), and 21 patients (11.8%) had transient or permanent neurological deficits.

CONCLUSIONS

The present meta-analysis for the radiosurgical management of brainstem CMs shows that SRS can decrease the rate of repeat hemorrhage and has a low rate of adverse effects compared with surgery. The authors suggest that SRS may be considered as an alternative treatment for brainstem CMs that are inoperable or have a high operative risk.

Stereotactic body radiotherapy in the treatment of pancreatic adenocarcinoma in elderly patients

Background

Treatment of pancreatic adenocarcinoma in the elderly is often complicated by comorbidities that preclude surgery, chemotherapy and/or conventional external beam radiation therapy (EBRT). Stereotactic body radiotherapy (SBRT) has thus garnered interest in this setting.

Methods

A retrospective review of 26 patients of age ≥ 80 with pancreatic adenocarcinoma treated with definitive SBRT+/-chemotherapy from 2007–2011 was performed. Twenty-seven percent of patients were stage I, 38% were stage II, 27% were stage III and 8% were stage IV. Patients most commonly received 24 Gy/1 fraction or 30-36 Gy/3 fractions. Kaplan-Meier was used to estimate overall survival (OS), local control (LC), cause specific survival (CSS) and freedom-from-metastatic disease (FFMD).

Results

The median age was 86 (range 80–91), and median follow-up was 11.6 months (3.5-24.6). The median planning target volume was 21.48 cm³ (6.1-85.09). Median OS was 7.6 months with 6/12 month OS rates of 65.4%/34.6%, respectively. Median LC was 11.5 months, 6-month and 12-month actuarial LC rates were 60.1% and 41.2%, respectively. There were no independent predictors for LC, but there was a trend for improved LC with prescription dose greater than 20 Gy (p = 0.063). Median CSS was 6.3 months, and 6-month and 12-month actuarial CSS were 53.8% and 23.1%, respectively. Median FFMD was 8.4 months, and 6-month and 12-month actuarial rates were 62.0% and 41.4%, respectively. Nine patients (47%) had local failures, 11 (58%) had distant metastasis, and 7 (37%) had both. There were no acute or late grade 3+ toxicities.

Conclusions

Definitive SBRT is feasible, safe and effective in elderly patients who have unresectable disease, have comorbidities precluding surgery or decline surgery.

American College of Radiology (ACR) and American Society for Radiation Oncology (ASTRO) Practice Guideline for the Performance of Stereotactic Radiosurgery (SRS)

American College of Radiology and American Society for Radiation Oncology Practice Guideline for the Performance of Stereotactic Radiosurgery (SRS). SRS is a safe and efficacious treatment option of a variety of benign and malignant disorders involving intracranial structures and selected extracranial lesions. SRS involves a high dose of ionizing radiation with a high degree of precision and spatial accuracy. A quality SRS program requires a multidisciplinary team involved in the patient management. Organization, appropriate staffing, and careful adherence to detail and to established SRS standards is important to ensure operational efficiency and to improve the likelihood of procedural success. A collaborative effort of the American College of Radiology and American Society for Therapeutic Radiation Oncology has produced a practice guideline for SRS. The guideline defines the qualifications and responsibilities of all the involved personnel, including the radiation oncologist, neurosurgeon, and qualified medical physicist. Quality assurance is essential for safe and accurate delivery of treatment with SRS. Quality assurance issues for the treatment unit, stereotactic accessories, medical imaging, and treatment-planning system are presented and discussed. Adherence to these practice guidelines can be part of ensuring quality and patient safety in a successful SRS program.

Dosimetric characteristics of the small diameter BrainLab™ cones used for stereotactic radiosurgery

The purpose was to study the dosimetric characteristics of the small diameter (≤10.0 mm) BrainLAB cones used for stereotactic radiosurgery (SRS) treatments in conjunction with a Varian Trilogy accelerator. Required accuracy and precision in dose delivery during SRS can be achieved only when the geometric and dosimetric characteristics of the small radiation fields is completely understood. Although a number of investigators have published the dosimetric characteristics of SRS cones, to our knowledge, there is no generally accepted value for the relative output factor (ROF) for the 5.0 mm diameter cone. Therefore, we have investigated the dosimetric properties of the small (≤10.0 mm) diameter BrainLAB SRS cones used in conjunction with the iPlan TPS and a Trilogy linear accelerator with a SRS beam mode. Percentage depth dose (PDD), off‐axis ratios (OAR), and ROF were measured using a SRS diode and verified with Monte Carlo (MC) simulations. The dependence of ROF on detector material response was studied. The dependence of PDD, OAR, and ROF on the alignment of the beam CAX with the detector motion line was also investigated using MC simulations. An agreement of 1% and 1 mm was observed between measurements and MC for PDD and OAR. The calculated ROF for the 5.0 mm diameter cone was 0.692±0.008 — in good agreement with the measured value of 0.683±0.007 after the diode response was corrected. Simulations of the misalignment between the beam axis and detector motion axis for angles between 0.5°–1.0° have shown a deviation > 2% in PDD beyond a certain depth. We have also provided a full set of dosimetric data for BrainLAB SRS cones. Monte Carlo calculated ROF values for cones with diameters less than 10.0 mm agrees with measured values to within 1.8%. Care should be exercised when measuring PDD and OAR for small cones. We recommend the use of MC to confirm the measurement under these conditions.

PACS numbers: 87.53.Ly, 87.55.‐x, 87.53.Bn, 87.55.K‐

Combining brain diagnosis and therapy in a single strategy: the safety, reliability, and cost implications using same-day versus separate-day stereotactic procedures

BACKGROUND

A therapeutic radiosurgery procedure usually follows a separate diagnostic stereotactic procedure after days or weeks.

OBJECTIVES

To define the clinical reliability, safety, and cost implications of same-day diagnostic stereotactic biopsy and therapeutic radiosurgery.

METHODS

During an 8-year interval, 26 patients underwent stereotactic brain biopsy followed by immediate therapeutic stereotactic radiosurgery in a single-day combined procedure. The intraoperative diagnosis was determined using standard histopathological techniques. Diagnostic accuracy, hospital costs, and contribution margins associated with this treatment strategy were compared to those of 26 case-matched patients (controls) who underwent a stereotactic diagnostic procedure followed by a separate-day outpatient SRS procedure within 6 weeks during the same time interval.

RESULTS

The intraoperative diagnosis correlated with the final histopathological diagnosis in 96% of the patients. Biopsy-related morbidity did not occur in this series. The mean total costs of same-day patients was significantly lower than the costs of patients who had two-stage procedures (USD 9,077 ± 2,366 vs. 11,284 ± 3,025; p = 0.008). The net contribution to the hospital margin of USD 13,736 was not significantly different between the two management strategies.

CONCLUSIONS

The advantages of the same-day approach included a single stereotactic head frame application, reduced total admission time, consecutive histopathological diagnosis and therapy in a single hospital admission, and reduced total hospital costs. For patients who are highly suspected to have a brain tumor for which SRS is likely to be an effective therapeutic strategy, same-day diagnostic stereotactic biopsy followed by therapeutic SRS proved to be a safe, reliable, and cost-effective management strategy.

Stereotactic body radiotherapy in the treatment of advanced adenocarcinoma of the pancreas

OBJECTIVES

The aim of the study was to assess the feasibility and safety of stereotactic body radiotherapy (SBRT) in patients with advanced pancreatic adenocarcinoma.

METHODS

We reviewed outcomes of 71 patients treated with SBRT for pancreatic cancer between July 2004 and January 2009. Forty patients (56%) had locally unresectable disease, 11 patients (16%) had local recurrence following surgical resection, 8 patients (11%) had metastatic disease, and 12 patients (17%) received adjuvant SBRT for positive margins. The median dose was 24 Gy (18-25 Gy), given in a single-fraction SBRT (n = 67) or fractionated SBRT (n = 4). Kaplan-Meyer survival analyses were used to estimate freedom from local progression (FFLP) and overall survival (OS) rates.

RESULTS

The median follow-up among surviving patients was 12.7 months (4-26 months). The median tumor volume was 17 mL (5.1-249 mL). The overall FFLP rates at 6 months/1 year were 71.7%/48.5%, respectively. Among those with macroscopic disease, FFLP was achieved in 77.3% of patients with tumor size <15 mL (n = 22), and 59.5% for ≥15 mL (n = 37) (P = 0.02). FFLP was achieved in 73% following 24 to 25 Gy, and 45% with 18 to 22 Gy (P = 0.004). The median OS was 10.3 months, with 6 month/1 year OS rates of 65.3%/41%, respectively. Grade 1-2 acute and late GI toxicity were seen in 39.5% of patients. Three patients experienced acute grade 3 toxicities.

CONCLUSIONS

SBRT is feasible, with minimal grade ≥3 toxicity. The overall FFLP rate for all patients was 64.8%, comparable to rates with external beam radiotherapy. This shorter treatment course can be delivered without delay in adjuvant systemic therapy.

Pontomedullary hemorrhage due to vascular malformation of basilar artery after treatment for acute lymphoblastic leukemia

In this letter the authors describe an acute lymphoblastic leukemia survivor with pontomedulary hemorrhage due to basilar artery malformation. Pathogenesis and management are discussed.