Placement of cesium-131 permanent brachytherapy seeds using the endoscopic endonasal approach for recurrent anaplastic skull base meningioma: case report and technical note.

There are few therapeutic options available for the treatment of recurrent meningiomas that have failed treatment with surgery and external-beam radiation therapy (EBRT). As additional EBRT is clinically risky, brachytherapy offers an important alternative for optimizing local control. In skull base meningiomas, the endoscopic endonasal approach (EEA) has demonstrated an excellent extent of resection. However, in the case of recurrent, atypical, or residual meningiomas, the EEA alone may not be adequate to address microscopic, residual, highly proliferative disease. In this situation, local radioactive seed brachytherapy has been shown to improve control, but few reports of this technique exist. A 48-year-old right-handed man presented on multiple occasions with recurrence of an anaplastic skull base meningioma, after multiple prior gross-total resections and multiple rounds of radiotherapy had failed. The authors performed a maximally safe neurosurgical tumor resection via EEA supplemented by the intraoperative implantation of 131Cs low-dose permanent brachytherapy seeds. They describe a technique for permanent implantation of brachytherapy seeds and provide operative video of this technique. The authors submit that utilizing this technique in combination with EEA tumor resection renders a minimally invasive approach to improving local control in a patient with a recurrent anaplastic or atypical meningioma of the skull base.

Accelerated Hypofractionated Radiotherapy in the Era of Concurrent Temozolomide Chemotherapy in Elderly Patients with Glioblastoma Multiforme.

Introduction Patients with glioblastoma multiforme (GBM) over age 65 represent nearly half of those diagnosed per annum. They have a different tumor markers profile, physiologic reserve, and a median survival as low as three to four months. An optimal treatment strategy in older GBM patients remains undefined, with many patients receiving radiation in 30 treatments over six weeks, a regimen based on trials originally excluding patients over age 70. Recent studies have suggested reducing the number of treatments to 10-15 over two to three weeks with similar efficacy. We present an elderly population of patients treated with six radiation treatments. Methods After IRB approval, we reviewed the electronic medical records of 20 consecutive patients over the age 60 at diagnosis with GBM, treated with maximally safe neurosurgical resection, and adjuvant hypofractionated radiation (HFRT) and temozolomide (TMZ) between 2012 and 2015. HFRT was given every other weekday for two weeks, in a total of six fractions (6 × 6 Gy to contrast-enhancing tumor +5 mm and 6 × 4 Gy to fluid-attenuated inversion recovery (FLAIR) +2 cm) with concurrent TMZ (75 mg/m2 daily), followed by adjuvant TMZ (150-200 mg/m2 in 5/28 days). The response was assessed using the Macdonald and Revised Assessment in Neuro-Oncology (RANO) criteria, radiology reports, physician notes, and tumor board consensus notes. Descriptive statistics, overall survival (OS), progression-free survival (PFS), toxicity, and steroid use were calculated and compared to the historical controls of patients treated with a six-week radiation regimen of 60 Gy in 30 fractions with TMZ.   Results The median age at diagnosis was 70.5 years (range: 61 - 82 years). Median pre-radiation Karnofsky performance scale (KPS) was 60 (range: 40 - 90). The median preoperative maximum gross tumor diameter on MRI was 3.6 cm (range: 1.8 - 6 cm). Six patients (30%) had a gross total resection (GTR), eight (40%) had a subtotal resection (STR), and six (30%) had biopsy only. The median progression-free survival was five months (95% (confidence interval) CI: 2.8, 16.4) and median OS of 14 months (95% CI: 5.0, upper limit not estimable). Of the 19 patients tested for isocitrate dehydrogenase-1 (IDH), 100% were negative. Of the eight patients who had MGMT methylation status results, four (50%) were positive for O6-methylguanine-DNA methyltransferase (MGMT) methylation. In the 18 patients who completed radiation, the HFRT treatment was well tolerated without any Grade 3/4 acute toxicities. Conclusions The accelerated adjuvant course of HFRT with TMZ used for the elderly with GBM decreases radiation treatment days to six. It was well tolerated in patients over 60 years of age and provided similar OS, PFS, minimal toxicity, and decreased steroid usage compared to historical controls treated with six or even two to three weeks of radiotherapy.

Clinical Outcomes of Large Brain Metastases Treated With Neurosurgical Resection and Intraoperative Cesium-131 Brachytherapy: Results of a Prospective Trial.

PURPOSE: Studies on adjuvant stereotactic radiosurgery to the cavity of resected brain metastases have suggested that larger tumors (>2.0 cm) have greater rates of recurrence and radionecrosis (RN). The present study assessed the effect of permanent low-dose 131Cs brachytherapy on local control and RN in patients treated for large brain metastases. METHODS AND MATERIALS: After institutional review board approval, 42 patients with 46 metastases ≥2.0 cm in preoperative diameter were accrued to a prospective trial from 2010 to 2015. Patients underwent surgical resection with intraoperative placement of stranded 131Cs seeds as permanent volume implants in the resection cavity. The primary endpoint was local freedom from progression (FFP). Secondary endpoints included regional and distant FFP, overall survival (OS), and RN rate. Failures 5 to 20 mm from the cavity and dural-based failures were considered regional. A separate analysis was performed for metastases >3.0 cm. RESULTS: Of the 46 metastases, 18 were >3.0 cm in diameter. The median follow-up period was 11.9 months (range 0.6-51.9). The metastases had a median preoperative diameter of 3.0 cm (range 2.0-6.8). The local FFP rate was 100% for all tumor sizes. Regional recurrence developed in 3 of 46 lesions (7%), for a 1-year regional FFP rate of 89% (for tumors >3.0 cm, the FFP rate was 80%, 95% confidence interval 54%-100%). Distant recurrences were found in 19 of 46 lesions (41%), for a 1-year distant FFP rate of 52%. The median OS was 15.1 months, with a 1-year OS rate of 58%. Lesion size was not significantly associated with any endpoint on univariate or multivariate analysis. Radioresistant histologic features resulted in worse survival (P=.036). No cases of RN developed. CONCLUSIONS: Intraoperative 131Cs brachytherapy is a promising and effective therapy for large brain metastases requiring neurosurgical intervention, which can offer improved local control and lower rates of RN compared with stereotactic radiosurgery to the resection cavity.

Radiation Exposure and Safety Precautions Following 131Cs Brachytherapy in Patients with Brain Tumors.

Cesium-131 (Cs) brachytherapy is a safe and convenient treatment option for patients with resected brain tumors. This study prospectively analyzes radiation exposure in the patient population who were treated with a maximally safe neurosurgical resection and Cs brachytherapy. Following implantation, radiation dose rate measurements were taken at the surface, 35 cm, and 100 cm distances. Using the half-life of Cs (9.69 d), the dose rates were extrapolated at these distances over a period of time (t = 30 d). Data from dosimetry badges and rings worn by surgeons and radiation oncologists were collected and analyzed. Postoperatively, median dose rate was 0.2475 mSv h, 0.01 mSv h, and 0.001 mSv h and at 30 d post-implant, 0.0298 mSv h, 0.0012 mSv h, and 0.0001 mSv h at the surface, 35 cm, and 100 cm, respectively. All but one badge and ring measured a dose equivalent corresponding to ~0 mSv h, while 1 badge measured 0.02/0.02/0.02 mSv h. There was a significant correlation between the number of seeds implanted and dose rate at the surface (p = 0.0169). When stratified by the number of seeds: 4-15 seeds (n = 14) and 20-50 seeds (n = 4) had median dose rates of 0.1475 mSv h and 0.5565 mSv h, respectively (p = 0.0015). Using National Council on Radiation Protection guidelines, this study shows that dose equivalent from permanent Cs brachytherapy for the treatment of brain tumors is limited, and it maintains safe levels of exposure to family and medical personnel. Such information is critical knowledge for the neurosurgeons, radiation oncologists, nurses, hospital staff, and family as this method is gaining nationwide popularity.

Cesium-131 brachytherapy for recurrent brain metastases: durable salvage treatment for previously irradiated metastatic disease.

OBJECTIVE Managing patients whose intraparenchymal brain metastases recur after radiotherapy remains a challenge. Intraoperative cesium-131 (Cs-131) brachytherapy performed at the time of neurosurgical resection may represent an excellent salvage treatment option. The authors evaluated the outcomes of this novel treatment with permanent intraoperative Cs-131 brachytherapy. METHODS Thirteen patients with 15 metastases to the brain that recurred after stereotactic radiosurgery and/or whole brain radiotherapy were treated between 2010 and 2015. Stranded Cs-131 seeds were placed as a permanent volume implant. Prescription dose was 80 Gy at 5-mm depth from the resection cavity surface. The primary end point was resection cavity freedom from progression (FFP). Resection cavity freedom from progression (FFP), regional FFP, distant FFP, median survival, overall survival (OS), and toxicity were assessed. RESULTS The median duration of follow-up after salvage treatment was 5 months (range 0.5-18 months). The patients' median age was 64 years (range 51-74 years). The median resected tumor diameter was 2.9 cm (range 1.0-5.6 cm). The median number of seeds implanted was 19 (range 10-40), with a median activity per seed of 2.25 U (range 1.98-3.01 U) and median total activity of 39.6 U (range 20.0-95.2 U). The 1-year actuarial local FFP was 83.3%. The median OS was 7 months, and 1-year OS was 24.7%. Complications included infection (3), pseudomeningocele (1), seizure (1), and asymptomatic radionecrosis (RN) (1). CONCLUSIONS After failure of prior irradiation of brain metastases, re-irradiation with intraoperative Cs-131 brachytherapy implants provides durable local control and limits the risk of RN. The authors' initial experience demonstrates that this treatment approach is well tolerated and safe for patients with previously irradiated tumors after failure of more than 1 radiotherapy regimen and that it results in excellent response rates and minimal toxicity.

Phase I/II study of resection and intraoperative cesium-131 radioisotope brachytherapy in patients with newly diagnosed brain metastases.

OBJECT: Resected brain metastases have a high rate of local recurrence without adjuvant therapy. Adjuvant whole-brain radiotherapy (WBRT) remains the standard of care with a local control rate > 90%. However, WBRT is delivered over 10-15 days, which can delay other therapy and is associated with acute and long-term toxicities. Permanent cesium-131 ((131)Cs) implants can be used at the time of metastatic resection, thereby avoiding the need for any additional therapy. The authors evaluated the safety, feasibility, and efficacy of a novel therapeutic approach with permanent (131)Cs brachytherapy at the resection for brain metastases. METHODS: After institutional review board approval was obtained, 24 patients with a newly diagnosed metastasis to the brain were accrued to a prospective protocol between 2010 and 2012. There were 10 frontal, 7 parietal, 4 cerebellar, 2 occipital, and 1 temporal metastases. Histology included lung cancer (16), breast cancer (2), kidney cancer (2), melanoma (2), colon cancer (1), and cervical cancer (1). Stranded (131)Cs seeds were placed as permanent volume implants. The prescription dose was 80 Gy at a 5-mm depth from the resection cavity surface. Distant metastases were treated with stereotactic radiosurgery (SRS) or WBRT, depending on the number of lesions. The primary end point was local (resection cavity) freedom from progression (FFP). Secondary end points included regional FFP, distant FFP, median survival, overall survival (OS), and toxicity. RESULTS: The median follow-up was 19.3 months (range 12.89-29.57 months). The median age was 65 years (range 45-84 years). The median size of resected tumor was 2.7 cm (range 1.5-5.5 cm), and the median volume of resected tumor was 10.31 cm(3) (range 1.77-87.11 cm(3)). The median number of seeds used was 12 (range 4-35), with a median activity of 3.82 mCi per seed (range 3.31-4.83 mCi) and total activity of 46.91 mCi (range 15.31-130.70 mCi). Local FFP was 100%. There was 1 adjacent leptomeningeal recurrence, resulting in a 1-year regional FFP of 93.8% (95% CI 63.2%-99.1%). One-year distant FFP was 48.4% (95% CI 26.3%-67.4%). Median OS was 9.9 months (95% CI 4.8 months, upper limit not estimated) and 1-year OS was 50.0% (95% CI 29.1%-67.8%). Complications included CSF leak (1), seizure (1), and infection (1). There was no radiation necrosis. CONCLUSIONS: The use of postresection permanent (131)Cs brachytherapy implants resulted in no local recurrences and no radiation necrosis. This treatment was safe, well tolerated, and convenient for patients, resulting in a short radiation treatment course, high response rate, and minimal toxicity. These findings merit further study with a multicenter trial.

Comparison of the epson expression 1680 flatbed and the vidar VXR-16 dosimetry PRO film scanners for use in IMRT dosimetry using gafchromic and radiographic film.

Intensity-modulated radiotherapy (IMRT) treatment plan verification is often done using Kodak EDR2 film and a Vidar Dosimetry PRO film digitizer. However, since many hospitals are moving towards a filmless environment, access to a film processor may not be available. Therefore, we have investigated a newly available Gafchromic EBT film for IMRT dosimetry. Planar IMRT dose distributions are delivered to both EBT and EDR2 film and scanned with the Vidar VXR-16 as well as an Epson Expression 1680 flatbed scanner. The measured dose distributions are then compared to those calculated with a Pinnacle treatment planning system. The IMRT treatments consisted of 7-9 6 MV beams for treatment of prostate, head and neck, and a few other sites. The films were analyzed using FilmQATM (3cognition LLC) software. Comparisons between measured and calculated dose distributions are reported as dose difference (DD) (pixels within +/-5%), distance to agreement (DTA) (3 mm), as well as gamma values (y) (dose= +/-3%, dist. =2 mm). Using EDR2 with the Vidar scanner is an established technique and agreement between calculated and measured dose distributions was better than 90% in all indices (DD, DTA, and gamma). However, agreement with calculations deteriorated reaching the lower 80% for EBT film scans with the Vidar scanner in logarithmic mode. The EBT Vidar scans obtained in linear mode showed an improved agreement to the upper 80% range, but artifacts were still observed across the scan. These artifacts were very distinct in all EBT scans and can be attributed to the way the film is transported through the scanner. In the Epson scanner both films are rigidly immobilized and the light source scans over the film. It was found that the Epson scanner performed equally well with both types of film giving agreement to better than 90% in all indices.