A prospective single-institution study of intraoperative radiotherapy (IORT) for early-stage breast cancer.

Intraoperative radiation therapy (IORT) is an option for breast-conserving therapy in early-stage breast cancer. IORT is given in one fraction at the time of surgery and eliminates the need for adjuvant external beam radiation therapy. However, previous trials indicate increased local failure rates compared with whole-breast irradiation, which engenders controversy around the appropriate use of IORT. We conducted a prospective study of patients diagnosed with early-stage breast cancer (T1-T2, N0-N1) at the University of Oklahoma Health Sciences Center (OUHSC) between 2013 and 2017 and treated with lumpectomy followed by intraoperative radiation therapy (IORT). Data collected included stage of disease, tumor location, histology, tumor markers, lymph node status, surgical margin size, recurrence, cosmetic outcomes, and length of follow-up. In-breast tumor recurrence rate (IBTR) in the 77 evaluable patients was 3.9% (3 patients). Margins were close (1 mm or less) in all three recurrent patients, and two were initially diagnosed with DCIS. Recurrence rates in our patients were comparable to prior reports. All recurrences were in patients with close margins indicating that this may represent a predictive feature for exclusion from IORT; additional studies are essential to determine the recurrence rates among patients treated with IORT and to identify potential predictors of IORT eligibility.

Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling.

The purpose of this study is to evaluate patient setup accuracy and quantify indi-vidual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head-and-neck masks, simu-lated with Brainlab localizer and planned with iPlan treatment planning system. Stereoscopic X-ray images (XC) are acquired and registered to corresponding digitally reconstructed radiographs using bony-anatomy matching to calculate 6D translational and rotational shifts. When the shifts are within tolerance (0.7 mm and 1°), treatment is initiated. Otherwise corrections are applied and additional X-rays (XV) are acquired to verify that patient position is within tolerance. The uncertain-ties from the mask, localizer, IR -frame, X-ray imaging, MV, and kV isocentricity are quantified individually. Mask uncertainty (translational: lateral, longitudinal, vertical; rotational: pitch, roll, yaw) is the largest and varies with patients in the range (-2.07-3.71 mm, -5.82-5.62 mm, -5.84-3.61 mm; -2.10-2.40°, -2.23-2.60°, and -2.7-3.00°) obtained from mean of XC shifts for each patient. Setup uncer-tainty in IR positioning (0.88, 2.12, 1.40 mm, and 0.64°, 0.83°, 0.96°) is extracted from standard deviation of XC. Systematic uncertainties of the frame (0.18, 0.25, -1.27mm, -0.32°, 0.18°, and 0.47°) and localizer (-0.03, -0.01, 0.03mm, and -0.03°, 0.00°, -0.01°) are extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the MV radiotherapy machine are (0.27, 0.24, 0.34 mm) and kV imager (0.15, -0.4, 0.21 mm). A statisti-cal model is developed to evaluate the individual and cumulative systematic and random positioning uncertainties induced by the different hardware and software components of the 6D ExacTrac system. The uncertainties from the mask, local-izer, IR frame, X-ray imaging, couch, MV linac, and kV imager isocentricity are quantified using statistical modeling.

Central nervous system metastasis in gynecologic cancer: symptom management, prognosis and palliative management strategies.

INTRODUCTION: CNS metastasis (CNSmet) with gynecologic malignancy (GM) is associated with poor prognosis and symptom burden. Two prognostic indices, the recursive partitioning analysis (RPA) and graded prognostic assessment (GPA), used in other solid tumors to guide intervention options were evaluated among GM patients. METHODS: Retrospective chart review was performed to identify patients with primary GM diagnosed with CNSmet from 2005-2014. RPA and GPA were applied and evaluated for goodness of fit. Long-term survivors (LTS) were those with survival time from CNSmet ≥9 months. RESULTS: 35 patients were identified with median age of 62 years (range, 41-78). The majority had ovarian cancer (54%). Median survival was 4.5 months (0.1-25.9), and median time from initial diagnosis was 2.6 years (0-19.6). Presenting symptoms varied but headache (57%) and altered mental status (23%) were most common. 37% had a solitary CNS lesion, 31% had 2-8, and 31% >8. 57% were treated with WBRT, 14% with stereotactic radiosurgery (SRS), and 20% with combinations of treatments, and 2 elected for hospice. 27% (9/33) of the patients were LTS. The GPA was not significantly associated with patient outcome (p=0.46). The RPA predicted time to death (p=.0010). CONCLUSION: Prognostic indices used to guide therapeutic interventions perform poorly in GM. Detection and aggressive symptom management are critical in maintaining QOL. Multidisciplinary consultation is critical to optimize outcomes and symptom control.

Dependency of planned dose perturbation (PDP) on the spatial resolution of MapCHECK 2 detectors.

The purpose of this study is to determine the dependency of the planned dose perturbation (PDP) algorithm (used in Sun Nuclear 3DVH software) on spatial resolution of the MapCHECK 2 detectors. In this study, ten brain (small target), ten brain (large target), ten prostate, and ten head-and-neck (H&N) cases were retrospectively selected for QA measurement. IMRT validation plans were delivered using the field-by-field technique with the MapCHECK 2 device. The measurements were performed using standard detector density (standard resolution; SR) and a doubled detector density (high resolution; HR) by merging regular with shifted measurements. SR and HR measurements were fed into the 3DVH software and ROI (region of interest), planning target volume (PTV), and organ at risk (OAR)) dose statistics (D95, Dmean, and Dmax) were determined for each. Differences of the dose statistics normalized to prescription dose for ROIs between original planning and PDP-perturbed planning were calculated for SR (ΔDSR) and HR (ΔDHR), and difference between ΔDSR and ΔDHR (ΔDSR-HR = ΔDSR - ΔDHR) was also calculated. In addition, 2D and 3D γ passing rates (GPRs) were determined for both resolutions, and a correlation between GPRs and ΔDSR or ΔDHR for PTV dose metrics was determined. No considerably high mean differences between ΔDSR and ΔDHR were found for almost all ROIs and plans (< 2%); however, |ΔDSR|, |ΔDHR|, and |ΔDSR-HR| for PTV were found to significantly increase as the PTV size decreased (e.g., PTV size < 5 cc). And statistically significant differences between SR and HR were observed for OARs proximal to targets in large brain target and H&N cases. As plan modulation represented by fractional MU/prescription dose (MU/cGy) became more complex, the 2D/3D GPRs tended to decrease; however, the modulation complexity did not make any noticeable distinctions in the DVH statistics of PTV between SR and HR, excluding the small brain cases whose PTVs were extremely small (PTV = 11.0 ± 10.1 cc). Moderate to strong negative correlations (-1 < r < -0.3) between GPRs and PTV dose metrics indicated that small clinical errors for PTV occur at the higher GPRs. In conclusion, doubling the detector density of the MapCHECK 2 device is recommended for small targets (i.e., PTV < 5 cc) and multiple targets with complex geometry with minimum setup error in the DVH-based plan evaluation.

Quantitative assessment by measurement and modeling of mobile target elongation in cone-beam computed tomographic imaging.

The purpose of this study was to assess quantitatively elongation of mobile targets in cone-beam CT (CBCT) imaging by measurement and modeling. A mathematical model was derived that predicts the measured lengths of mobile targets and its dependence on target size and motion patterns in CBCT imaging. Three tissue-equivalent targets of differing sizes were inserted in an artificial thorax phantom to simulate lung lesions. Respiratory motion was mimicked with a mobile phantom that moves in one-dimension along the superior-inferior direction at a respiration frequency of 0.24 Hz for eight different amplitudes in the range 0-40 mm. A mathematical model was derived to quantify the variations in target lengths and its dependence on phantom motion parameters in CBCT. Predictions of the model were verified by measurement of the lengths of mobile targets in CBCT images. The model predicts that target lengths increased linearly with increase in speed and amplitude of phantom motion in CBCT. The measured lengths of mobile targets imaged with CBCT agreed with the calculated lengths within half-slice thickness spatial resolution. The maximal length of a mobile target was independent of the frequency and phase of motion. Elongation of mobile targets was similar in half-fan and full-fan CBCT for similar motion patterns, as long as the targets remained within the imaging view. Mobile targets elongated linearly with phantom speed and motion amplitude in CBCT imaging. The model introduced in this work assessed quantitatively the variation in target lengths induced by motion, which may be a useful tool to consider elongations of mobile targets in CBCT applications in diagnostic imaging and radiotherapy.

NRG Oncology/RTOG1205: A Randomized Phase II Trial of Concurrent Bevacizumab and Reirradiation Versus Bevacizumab Alone as Treatment for Recurrent Glioblastoma.

PURPOSE: To assess whether reirradiation (re-RT) and concurrent bevacizumab (BEV) improve overall survival (OS) and/or progression-free survival (PFS), compared with BEV alone in recurrent glioblastoma (GBM). The primary objective was OS, and secondary objectives included PFS, response rate, and treatment adverse events (AEs) including delayed CNS toxicities. METHODS: NRG Oncology/RTOG1205 is a prospective, phase II, randomized trial of re-RT and BEV versus BEV alone. Stratification factors included age, resection, and Karnofsky performance status (KPS). Patients with recurrent GBM with imaging evidence of tumor progression ≥ 6 months from completion of prior chemo-RT were eligible. Patients were randomly assigned 1:1 to re-RT, 35 Gy in 10 fractions, with concurrent BEV IV 10 mg/kg once in every 2 weeks or BEV alone until progression. RESULTS: From December 2012 to April 2016, 182 patients were randomly assigned, of whom 170 were eligible. Patient characteristics were well balanced between arms. The median follow-up for censored patients was 12.8 months. There was no improvement in OS for BEV + RT, hazard ratio, 0.98; 80% CI, 0.79 to 1.23; P = .46; the median survival time was 10.1 versus 9.7 months for BEV + RT versus BEV alone. The median PFS for BEV + RT was 7.1 versus 3.8 months for BEV, hazard ratio, 0.73; 95% CI, 0.53 to 1.0; P = .05. The 6-month PFS rate improved from 29.1% (95% CI, 19.1 to 39.1) for BEV to 54.3% (95% CI, 43.5 to 65.1) for BEV + RT, P = .001. Treatment was well tolerated. There were a 5% rate of acute grade 3+ treatment-related AEs and no delayed high-grade AEs. Most patients died of recurrent GBM. CONCLUSION: To our knowledge, NRG Oncology/RTOG1205 is the first prospective, randomized multi-institutional study to evaluate the safety and efficacy of re-RT in recurrent GBM using modern RT techniques. Overall, re-RT was shown to be safe and well tolerated. BEV + RT demonstrated a clinically meaningful improvement in PFS, specifically the 6-month PFS rate but no difference in OS.

Long-Term Update of NRG/RTOG 0522: A Randomized Phase 3 Trial of Concurrent Radiation and Cisplatin With or Without Cetuximab in Locoregionally Advanced Head and Neck Cancer.

PURPOSE: The combination of cisplatin and radiation or cetuximab and radiation improves overall survival of patients with locoregionally advanced head and neck carcinoma. NRG Oncology conducted a phase 3 trial to test the hypothesis that adding cetuximab to radiation and cisplatin would improve progression-free survival (PFS). METHODS AND MATERIALS: Eligible patients with American Joint Committee on Cancer sixth edition stage T2 N2a-3 M0 or T3-4 N0-3 M0 were accrued from November 2005 to March 2009 and randomized to receive radiation and cisplatin without (arm A) or with (arm B) cetuximab. Outcomes were correlated with patient and tumor features. Late reactions were scored using Common Terminology Criteria for Adverse Events (version 3). RESULTS: Of 891 analyzed patients, 452 with a median follow-up of 10.1 years were alive at analysis. The addition of cetuximab did not improve PFS (hazard ratio [HR], 1.06; 95% confidence interval [CI], 0.89-1.26; P = .74), with 10-year estimates of 43.6% (95% CI, 38.8- 48.4) for arm A and 40.2% (95% CI, 35.4-45.0) for arm B. Cetuximab did not reduce locoregional failure (HR, 1.21; 95% CI, 0.95-1.53; P = .94) or distant metastasis (HR, 0.79; 95% CI, 0.54-1.14; P = .10) or improve overall survival (HR, 0.97; 95% CI, 0.80-1.16; P = .36). Cetuximab did not appear to improve PFS in either p16-positive oropharynx (HR, 1.30; 95% CI, 0.87-1.93) or p16-negative oropharynx or nonoropharyngeal primary (HR, 0.94; 95% CI, 0.73-1.21). Grade 3 to 4 late toxicity rates were 57.4% in arm A and 61.3% in arm B (P = .26). CONCLUSIONS: With a median follow-up of more than 10 years, this updated report confirms the addition of cetuximab to radiation therapy and cisplatin did not improve any measured outcome in the entire cohort or when stratifying by p16 status.

Surgical perspectives from a prospective, nonrandomized, multicenter study of breast conserving surgery and adjuvant electronic brachytherapy for the treatment of breast cancer.

BACKGROUND: Accelerated partial breast irradiation (APBI) may be used to deliver radiation to the tumor bed post-lumpectomy in eligible patients with breast cancer. Patient and tumor characteristics as well as the lumpectomy technique can influence patient eligibility for APBI. This report describes a lumpectomy procedure and examines patient, tumor, and surgical characteristics from a prospective, multicenter study of electronic brachytherapy. METHODS: The study enrolled 65 patients of age 45-84 years with ductal carcinoma or ductal carcinoma in situ, and 44 patients, who met the inclusion and exclusion criteria, were treated with APBI using the Axxent® electronic brachytherapy system following lumpectomy. The prescription dose was 34 Gy in 10 fractions over 5 days. RESULTS: The lumpectomy technique as described herein varied by site and patient characteristics. The balloon applicator was implanted by the surgeon (91%) or a radiation oncologist (9%) during or up to 61 days post-lumpectomy (mean 22 days). A lateral approach was most commonly used (59%) for insertion of the applicator followed by an incision site approach in 27% of cases, a medial approach in 5%, and an inferior approach in 7%. A trocar was used during applicator insertion in 27% of cases. Local anesthetic, sedation, both or neither were administered in 45%, 2%, 41% and 11% of cases, respectively, during applicator placement. The prescription dose was delivered in 42 of 44 treated patients. CONCLUSIONS: Early stage breast cancer can be treated with breast conserving surgery and APBI using electronic brachytherapy. Treatment was well tolerated, and these early outcomes were similar to the early outcomes with iridium-based balloon brachytherapy.

Linear accelerator based intracranial and extracranial stereotactic radiation therapy at the University of Oklahoma.

PURPOSE: Review our institutional outcomes with linear accelerator based stereotactic radiation therapy at the University of Oklahoma. METHODS: We retrospectively reviewed all patients treated in our department with linear accelerator based stereotactic radiation therapy since we implemented this modality in 2008. Thirty-seven patients have been treated with a mean follow-up of 8.3 months. Seventeen patients had tumors near critical structures; ten had treatment sites not suited for gamma knife therapy. Outcomes are reviewed for efficacy and toxicity. RESULTS: Acute and long term complications reported are minimal. Stabilization of treatment sites was achieved in 96% of patients on follow-up imaging. Thirteen patients (35%) have died, of which eleven died to systemic disease progression outside of the treatment site. No treatment related deaths occurred. CONCLUSIONS: Stereotactic radiation therapy is a successful treatment modality to achieve local disease control with minimal toxicity. We plan to expand its use and applications in the future.

Treatment of Recurrent Optic Nerve Sheath Meningioma With a Secondary Course of Radiotherapy.

Optic nerve sheath meningiomas (ONSM) are benign neoplasms found surrounding the optic nerve that can affect vision, and potentially lead to blindness. The use of radiotherapy has been advocated to improve visual outcomes and minimize the risk of complications. We present a case of a 58-year-old woman who was treated with a second course of radiotherapy 27-years after initial radiotherapy for recurrent ONSM. The patient responded well to the second course of radiotherapy with good clinical and visual outcomes. This case report supports evidence that treatment with radiotherapy can improve visual outcomes in patients with recurrent ONSM with mild to moderate re-irradiation-related side effects.

Resection and radiotherapy for intracranial ependymoma: a multiinstitutional 50-year experience.

OBJECTIVE: Maximal safe resection is the standard-of-care treatment for adults with intracranial ependymoma. The value of adjuvant radiotherapy remains unclear as these tumors are rare and current data are limited to a few retrospective cohort studies. In this study, the authors assembled a cohort of patients across multiple international institutions to assess the utility of adjuvant radiotherapy in this patient population. METHODS: Adults with intracranial ependymoma managed surgically at the University Health Network in Toronto, Canada, the University of Oklahoma Health Sciences Center in Oklahoma City, Oklahoma, and The Ottawa Hospital in Ottawa, Canada, were included in this study. The primary end points were progression-free survival (PFS) and overall survival (OS). Clinicopathological variables were assessed in univariate and multivariate Cox proportional hazard models for prognostic significance of PFS and OS. RESULTS: A total of 122 patients diagnosed between 1968 and 2019 were identified for inclusion. The majority of patients had grade II ependymomas on histopathology (78%) that were infratentorially located (71%), underwent gross-total (GTR) or near-total resection (NTR; 55%), and were treated with adjuvant radiotherapy (67%). A volumetric analysis of the extent of resection in 49 patients with available tumor volume data supported the accuracy of the categorical GTR, NTR, and subtotal resection (STR) groups utilized. Independent statistically significant predictors of poorer PFS in the multivariate analysis included STR or biopsy (vs GTR/NTR; HR 5.4, 95% confidence interval [CI] 2.4-11.0, p < 0.0001) and not receiving adjuvant radiotherapy; cranial (HR 0.5, 95% CI 0.2-1.1) and craniospinal (HR 0.2, 95% CI 0.04-0.5) adjuvant radiotherapy regimens improved PFS (p = 0.0147). Predictors of poorer OS in the multivariate analysis were grade III histopathology (vs grade II: HR 5.7, 95% CI 1.6-20.2, p = 0.0064) and undergoing a biopsy/STR (vs GTR/NTR: HR 9.8, 95% CI 3.2-30.1, p = 0.0001). CONCLUSIONS: The results of this 50-year experience in treating adult intracranial ependymomas confirm an important role for maximal safe resection (ideally GTR or NTR) and demonstrate that adjuvant radiotherapy improves PFS. This work will guide future studies as testing for molecular ependymoma alterations become incorporated into routine clinical practice.

Evaluation of the setup accuracy of a stereotactic radiotherapy head immobilization mask system using kV on-board imaging.

The purpose of this study was to evaluate setup accuracy and quantify random and systematic errors of the BrainLAB stereotactic immobilization mask and localization system using kV on-board imaging. Nine patients were simulated and set up with the BrainLAB stereotactic head immobilization mask and localizer to be treated for brain lesions using single and hypofractions. Orthogonal pairs of projections were acquired using a kV on-board imager mounted on a Varian Trilogy machine. The kV projections were then registered with digitally-reconstructed radiographs (DRR) obtained from treatment planning. Shifts between the kV images and reference DRRs were calculated in the different directions: anterior-posterior (A-P), medial-lateral (R-L) and superior-inferior (S-I). If the shifts were larger than 2mm in any direction, the patient was reset within the immobilization mask until satisfying setup accuracy based on image guidance has been achieved. Shifts as large as 4.5 mm, 5.0 mm, 8.0 mm in the A-P, R-L and S-I directions, respectively, were measured from image registration of kV projections and DRRs. These shifts represent offsets between the treatment and simulation setup using immobilization mask. The mean offsets of 0.1 mm, 0.7 mm, and -1.6 mm represent systematic errors of the BrainLAB localizer in the A-P, R-L and S-I directions, respectively. The mean of the radial shifts is about 1.7 mm. The standard deviations of the shifts were 2.2 mm, 2.0 mm, and 2.6 mm in A-P, R-L and S-I directions, respectively, which represent random patient setup errors with the BrainLAB mask. The Brain-LAB mask provides a noninvasive, practical and flexible immobilization system that keeps the patients in place during treatment. Relying on this system for patient setup might be associated with significant setup errors. Image guidance with the kV on-board imager provides an independent verification technique to ensure accuracy of patient setup. Since the patient may relax or move during treatment, uncontrolled and undetected setup errors may be produced with patients that are not well-immobilized. Therefore, the combination of stereotactic immobilization and image guidance achieves more controlled and accurate patient setup within 2mm in A-P, R-L and S-I directions.

Quantitative evaluation of increase in surface dose by immobilization thermoplastic masks and superficial dosimetry using Gafchromic EBT film and Monte Carlo calculations.

PURPOSE: To investigate the increase in surface dose under immobilization thermoplastic masks by measurements and calculation in the build-up region using Gafchromic films and Monte Carlo simulation. MATERIALS AND METHODS: Surface doses were measured underneath three thermoplastic masks in open fields using 6 and 18 MV photon beams. These masks are used to immobilize patients for head and neck (H&N), pelvis and thoracic treatment. Gafchromic EBT films were placed on the top of the flat surface of a phantom partially underneath the mask and exposed in open 10 x 10 cm2 photon fields. The depth doses were calculated using BEAMnrc Monte Carlo code for water-equivalent film detectors with different layers of thickness ranging from 50 microm to 2.5 mm and compared with film measurements. RESULTS: Surface dose increased by a factor of 3 to 4 underneath the mask relative to the open areas and 6 MV beam delivers more skin dose than 18 MV. H&N mask increased surface dose by a factor of 3 using 18 MV and a factor of 4 using 6 MV. In addition, increase in surface dose depended on the type of the mask, the size of openings, and the amount of stretching performed during the mask preparation. The measured depth doses were compared with BEAMnrc Monte Carlo calculation for water-equivalent detectors using different sizes. The calculated depth dose depended significantly on the thickness of film detector and varies by more than 15% using layer thickness of 2.5 mm compared to 50 microm. Surface doses measured by Gafchromic EBT films agreed within 3% with the Monte Carlo calculations using a small detector layer of 50 microm. CONCLUSION: Thermoplastic masks used for patient immobilization can significantly increase skin doses by up to a factor of 4 more than that without the mask using 6 MV beams. The skin reactions resulting from thermoplastic masks should be monitored and corrective measures should be taken during treatment such as partially removing the mask over skin areas with complications and optimizing the skin dose in IMRT planning. Gafchromic EBT films provide accurate skin dosimetry which agrees within 3% with Monte Carlo calculations. Gafchromic EBT film makes an excellent tool for measuring depth doses in the buildup region and these data can be applied for treatment planning calculations and IMRT optimization.

Laser Interstitial Thermal Therapy for Metastatic Melanoma After Failed Radiation Therapy: A Case Series.

BACKGROUND: Laser interstitial thermal therapy (LITT) is a growing technology to treat a variety of brain lesions. It offers an alternative to treatment options, such as open craniotomy and stereotactic radiosurgery. OBJECTIVE: To analyze our experience using LITT for metastatic melanoma. METHODS: This is a retrospective chart review of the patients from our institution. Our case series involves 5 patients who had previously failed radiation treatment. RESULTS: Our patients have low complication rates and short hospital stays. Both are considerably lower when compared to the literature for metastatic melanoma. CONCLUSION: LITT is a safe therapy, with few complications and short hospital stays.

A comparative study of seed localization and dose calculation on pre- and post-implantation ultrasound and CT images for low-dose-rate prostate brachytherapy.

This work investigates variation in the volume of the prostate measured at different stages through the prostate brachytherapy procedure for 30 patients treated with I-125 radioactive seeds. The implanted seeds were localized on post-implantation ultrasound (US) images and the effect of prostate enlargement due to edema on dose coverage for 15 patients was studied. The volume of the prostate was measured at four stages as follows: (a) 2-3 weeks prior to implantation using US imaging, (b) then at the start of the intra-operative prostate brachytherapy procedure on the day of the implant, (c) immediately post-implantation using US imaging in the operating room and (d) finally by CT imaging at nearly 4 weeks post-implantation. Comparative prostate volume studies were performed using US imaging stepper and twister modes. For the purpose of this study, the implanted seeds were localized successfully on post-implant ultrasound twister images, retrospectively. The plans using post-implant US imaging were compared with intra-operative plans on US and plans created on CT images. The prostate volume increases about 10 cm(3) on average due to edema induced by needle insertion and seed loading during implantation. The visibility of the implanted seeds on US twister images acquired post-implantation is as good as those on CT images and can be localized and used for dose calculation. The dose coverage represented by parameters such as D90 (dose covering 90% of the volume) and V100 (volume covered by 100% dose) is poorer on plans performed on post-implantation twister US studies than on the intra-operative live plan or the CT scan performed 4 weeks post-operatively. For example, the mean D90 difference on post-implantation US is lower by more than 15% than that on pre-implantation US. The volume enlargement of the prostate due to edema induced by needle insertion and seed placement has a significant effect on the quality of dosimetric coverage in brachytherapy prostate seed implants. Here, we introduced a new approach based on the use of post-implant US twister images to correct for prostate enlargement intra-operatively. Besides the ability to localize the seeds and superior soft tissue visibility, the twister US images include effects of the enlargement of the prostate gland and seed migration during the implantation procedure.

Bilateral Carotid-cavernous Fistulas Treated with Partial Embolization and Radiosurgery.

Bilateral carotid-cavernous fistulas (CCFs) are rare. In this paper, we report the case of an 88-year-old woman who presented with a two-month history of worsening visual symptoms and was subsequently found to have bilateral Barrow grade D CCFs. Cannulation and complete embolization of the offending vessels during angiography proved unsuccessful, and so the patient underwent adjuvant radiosurgery as salvage therapy with a good clinical outcome. This case adds to the limited but growing literature on the multi-modal management of CCFs.

Factors Associated with Treatment Failure and Radiosurgery-Related Edema in WHO Grade 1 and 2 Meningioma Patients Receiving Gamma Knife Radiosurgery.

BACKGROUND: Before the advent of radiosurgery, neurosurgical treatment of meningiomas typically involved gross total resection of the mass whenever surgery was deemed possible. Over the past 4 decades, though, Gamma Knife radiosurgery (GKRS) has proved to be an effective, minimally invasive means to control the growth of these tumors. However, the variables associated with treatment failure (regrowth or clinical progression) after GKRS and GKRS-related complications, such as cerebral edema, are less well understood. METHODS: We retrospectively collected data between 2009 and 2018 for patients who underwent GKRS for meningiomas. After data collection, we performed univariate and multivariable modeling of the factors that predict treatment failure and cerebral edema after GKRS. Hazard ratios (HR) and P values were determined for these variables. RESULTS: Fifty-two patients were included our analysis. The majority of patients were female (38/52,73%), and nearly all patients presented with a suspected or confirmed World Health Organization grade 1 meningioma (48/52, 92%). The median tumor volume was 3.49 cc (range, 0.22-20.11 cc). Evidence of meningioma progression after treatment developed in 5 patients (10%), with a median time to continued tumor growth of 5.9 months (range, 2.7-18.3 months). In multivariable analysis, patients in whom treatment failed were more likely to be male (HR = 8.42, P = 0.045) and to present with larger tumor volumes (HR = 1.27, P = 0.011). In addition, 5 patients (10%) experienced treatment-related cerebral edema. On univariate analysis, patients who experienced cerebral edema were more likely present with larger tumors (HR = 1.16, P = 0.028). CONCLUSIONS: Increasing meningioma size and male gender predispose to meningioma progression after treatment with GKRS. Increasing tumor size also predicts the development of postradiosurgery cerebral edema.

Dosimetric comparison of sector-blocked and non-sector-blocked Gamma Knife Perfexion treatment plans for trigeminal neuralgia.

The purpose of this study is to compare the quality of trigeminal neuralgia (TN) treatment plans with and without utilizing sector blocking. Twelve patients with 13 cases of TN were evaluated in this retrospective study. Identical magnetic resonance imaging (MRI) contour sets and prescription doses used in treatments were reused for all plans. Treatment plans were compared on the basis of the amount of dose received by critical structures (i.e., brainstem, ipsilateral temporal lobe, optic chiasm, optic nerves, cochlea) and the estimated total treatment time. The use of sector blocking resulted in a statistically significant decrease in the radiation dose to the brainstem but increased doses to the cerebellum and temporal lobe regions. The magnitude of these differences was small and individual patient anatomy specific. The use of sector blocking also resulted in a statistically significant increase in the treatment time. The magnitude of the change in treatment time was dependent on the number of sectors blocked. Our study suggests some potential benefits, as well as disadvantages, to the use of sector blocking in the treatment of TN. Treatment decision needs to be individualized based on the patient's anatomy and overall condition.

Comparison of Volumetric Modulated Arc Therapy and Intensity Modulated Radiation Therapy for Whole Brain Hippocampal Sparing Treatment Plans Based on Radiobiological Modeling.

INTRODUCTION: In this article, we report the results of our investigation on comparison of radiobiological aspects of treatment plans with linear accelerator-based intensity-modulated radiation therapy and volumetric-modulated arc therapy for patients having hippocampal avoidance whole-brain radiation therapy. MATERIALS AND METHODS: In this retrospective study using the dose-volume histogram, we calculated and compared biophysical indices of equivalent uniform dose, tumor control probability, and normal tissue complication probability (NTCP) for 15 whole-brain radiotherapy patients. RESULTS AND DISCUSSIONS: Dose-response models for tumors and critical structures were separated into two groups: mechanistic and empirical. Mechanistic models formulate mathematically with describable relationships while empirical models fit data through empirical observations to appropriately determine parameters giving results agreeable to those given by mechanistic models. CONCLUSIONS: Techniques applied in this manuscript could be applied to any other organs or types of cancer to evaluate treatment plans based on radiobiological modeling.

Clinicopathologic Features and Radiation Therapy Utilization in Patients with Male Breast Cancer: A National Cancer Database Study.

Male breast cancer (MBC) accounts for approximately 1% of all breast cancers, limiting the data characterizing clinicopathologic features and treatment outcomes in patients with MBC. This paucity of data has led to most of our treatment guidance being extrapolated from patients with female breast cancer (FBC). From 1998 to 2012, data were captured using the National Cancer Database to identify patients with nonmetastatic MBC (n = 23 305) and FBC (n = 2 678 061). Tumor and clinicopathologic features were obtained and compared. Patients with MBC were more likely to have invasive disease, T2-4 tumors, centrally located tumors, positive lymph nodes, estrogen receptor-positive or progesterone receptor-positive tumors, lymphovascular space invasion, and were less likely to have Her2/neu-positive or triple-negative tumors. All of these differences were statistically significant (P < .001). Treatment comparisons showed that patients with MBC were more likely to undergo mastectomy and less likely to undergo breast-conserving surgery with postoperative radiation utilization found to be less in patients with MBC, both as part of breast-conserving therapy (BCT) and for postmastectomy radiation treatment (PMRT) (P < .001). Stage-by-stage comparisons showed that median survival, 5-year, and 10-year overall survival (OS) rates are lower in patients with MBC vs patients with FBC (P < .001). The utilization of adjuvant radiation, both BCT and PMRT, was shown to improve 5- and 10-year OS (P < .001). Male breast cancer clinicopathologic features appear to be unfavorable in relation to FBC and adjuvant radiation is shown beneficial in survival outcomes. Further investigation is needed to help guide future utilization and treatment with radiation, systemic, and endocrine manipulation in this small population of patients with MBC.