Ultra-hypofractionated radiotherapy (UHF RT) is revolutionizing the treatment approach for low- and intermediate-risk prostate cancer patients. This study reports the planning process of UHF RT utilizing the cone beam computed tomography (CBCT)-based online adaptive radiotherapy (OART) treatment with the Ethos system, focusing on a comparative analysis between OART and image-guided radiotherapy (IGRT) plans. We also assessed the pre-planning capabilities of the Ethos system against the CyberKnife (CK) (Accuray, Sunnyvale, CA) system. A 66-year-old patient, diagnosed with prostatic acinar adenocarcinoma confirmed via biopsy and presenting with elevated prostate-specific antigen (PSA) levels, underwent UHF OART treatment using the Ethos system. The planning encompassed delineating the gross target volume (GTV) as the prostate, while the clinical target volume (CTV) comprised the prostate and proximal seminal vesicle. The planning target volume (PTV) was derived from the CTV with a 5 mm external margin except for a 3 mm posterior margin. A simultaneous integrated boost (SIB) technique was employed, delivering 40 Gy in five fractions (8 Gy per fraction) to the gross tumor volume (GTV) and 36.25 Gy in five fractions (7.25 Gy per fraction) to the remaining part of the planning target volume (PTV), with treatments scheduled biweekly. We compared OART and IGRT plans and conducted a comparative analysis between Ethos planning and the CK system for pre-planning assessment. When comparing Ethos planning and CK plans, Ethos demonstrated slightly better target coverage and organ-at-risk (OAR) sparing. However, CK plans showed superior containment of low-dose spillage, particularly at 50% and 25% iso-doses, due to non-coplanar beam arrangements. Our results demonstrated that OART plans yielded superior target coverage and improved OAR sparing compared to IGRT plans. Notably, the entire OART process, from planning to delivery, was accomplished within 27 minutes. The Ethos OART system\'s ability to adapt to daily anatomical changes, efficient workflow, and superior OAR-sparing capabilities make it a promising option for prostate cancer treatment using UHF RT.

Steroids are commonly used for medical purposes. While hiccups are a recognized side effect of steroid therapy, we have not found any reports of hiccups interfering with the progress of radiotherapy. A case of dexamethasone (DEX)-induced hiccups (DIH) during CyberKnife radiotherapy (CKR) is presented. A 42-year-old man with neurofibromatosis type I had a history of malignant peripheral schwannomas originating in the right femur. We started to perform CKR with oral DEX at an increased dose of 4 mg/day for the recurrence of cranial metastasis and primary lesions. Severe hiccups developed four days after the increased DEX dose. DEX was stopped six days after CKR initiation, and the hiccups subsided over the next four days. However, the CKR procedure was not possible due to the patient\'s worsening swelling of the head and thigh lesions, which prevented the proper fit of the mesh face mask and body fixation device. Intravenous (IV) DEX 6.6 mg/day was initiated, which allowed the resumption of CKR due to reduced swelling of the lesions. The CKR was completed due to the absence of hiccups following the transition to IV DEX. DIH could occur even at a dosage of 4 mg/day when taken orally. Our case suggests the significance of recognizing DIH during radiotherapy. Switching the administration from oral to IV DEX may be an option for dealing with DIH.

UNASSIGNED: Uveal melanoma is the most common primary intraocular malignancy in adults, affecting primarily the choroid of the eye. Plaque brachytherapy is the most common procedure for the treatment of small choroidal melanoma, especially in posteriorly located tumors. However, modern radiotherapy techniques, such as CyberKnife or Gamma knife stereotactic radiosurgery (SRS) and proton beam radiotherapy, have shown better results in tumor control and eye retention. Recent studies have indicated that SRS is a promising non-invasive, single-session treatment option, with most studies reporting the best outcomes when using ≥21-22 Gy. However, there is no consistent protocol for managing this pathology using CyberKnife, not only in terms of dose but also fractions.
UNASSIGNED: Here, we report the first case series of patients (n = 4, age range 38-64 years, median age 52.5 years) with choroidal UM in Central America who were treated with CyberKnife SRS (22 Gy in one session). During the follow-up (range 25-29 months, median 27.5 months), a 100% control rate with no systemic metastatic disease has been achieved. We found a statistically significant reduction in the largest basal diameter at 24 months for all tumors. However, visual acuity has progressively decreased in most patients. Notably, two of our patients developed radiation maculopathy, and the other two developed radiation retinopathy after SRS.
UNASSIGNED: Our findings suggest that future studies should evaluate the use of different prophylactic therapies to prevent the development of side effects. The clinical management of toxicities presented in our report can serve as a reference in the clinical practice of other centers. Our report supports the growing body of evidence showing that CyberKnife radiosurgery is a safe and effective therapeutic option for the treatment of UM.

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin tumor. Herein, we present a case of MCC which was successfully treated with radiotherapy alone using CyberKnife® (CK) (Accuray Incorporated, Sunnyvale, California, United States). An 86-year-old female patient presented with multiple painless pink rash skin tumors on the left cheek. The patient was diagnosed with MCC based on a lesion biopsy (T2cN2M0, stage IIIB). The patient was referred for CK radiotherapy (CKR) at our institution because of her advanced age and inoperative lesions. The patient underwent CKR alone, with a planning target volume (PTV) of 14.9 ml, a prescribed dose of 30 Gy, a maximum dose of 46.2 Gy, and an isodose line (the minimum dose of 95% of the PTV) of 65% in 10 fractions for 13 days. The lesions had completely regressed on the last day of CKR. Left cervical lymph node metastasis (CLNM) appeared 10 months after CKR. The patient underwent a second CKR for CLNM, the PTV was 4.6 ml, and the prescribed dose was 27 Gy in three fractions for three days. The CLNM had completely regressed one month later after the second CKR. Primary lesions did not recur for 33 months after the initial CKR, and CLNM did not reappear for 23 months after the second CKR with good cosmetic results. No CKR-related adverse event occurred in our follow-up period. Our present case indicates that CKR is an effective treatment option for patients with MCC, particularly elderly patients who may not be suitable candidates for extensive surgical resection.

Trigeminal neuralgia (TN) is a paroxysmal, unilateral, brief, shock-like pain in ≥1 divisions of the trigeminal nerve. It can result from multiple causes; however, TN secondary to stroke is very rare.
We present the case of TN secondary to pontine infarction treated with incremental doses of neuropathic pain medication for >5 years before conservative management failed. He was then treated with stereotactic radiosurgery (SRS). Additionally, we conducted a systematic review using standard PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines for all the cases of TN with brainstem stroke from 1976 to 2022.
Our patient was an 82-year-old man. Magnetic resonance imaging demonstrated a pontine lesion consistent with stroke. The Barrow Neurological Institute (BNI) score at presentation was 5. He received a marginal dose of 60 Gy to the 80% isodose line in a single fraction to a volume of 0.05 cm3. The immediate post-treatment BNI score was 0 and remained at 0 for 3 months, when he experienced recurrence. The recurrence was treated with oxcarbazepine. His pain remained well controlled with a lower dose of oxcarbazepine, and he had no adverse effects at 1 year of follow-up with a BNI score of 3. The systemic review identified 21 case reports with a combined cohort of 25 patients with TN secondary to stroke. Only 3 patients were treated with SRS, 2 of whom reported symptom improvement at 6 months and 8 months of follow-up with no adverse events.
Our case and literature review demonstrate durable and effective treatment with SRS, which can be considered a safe and effective treatment option for patients with stroke-associated TN.

Esthesioneuroblastoma (ENB), also known as olfactory neuroblastoma, is a rare malignant tumor of neuroectodermal origin that arises from the olfactory epithelium. We present a case of ENB metastasizing through the leptomeningeal route to the spinal dura, which was treated with CyberKnife (CK) stereotactic radiosurgery (SRS), and aim to assess the safety and effectiveness of SRS in such cases. To the best of our knowledge, this is the first case report in the literature that discusses ENB spinal leptomeningeal metastases treated with CK radiosurgery. We retrospectively review the clinical and radiological outcomes in a 70-year-old female with ENB metastasis to the spine. Progression-free survival (PFS), overall survival (OS), and local tumor control (LTC) are investigated. In our patient, ENB had been diagnosed at the age of 58 years and spinal metastases had been first noted at the age of 65 years. A total of six spinal lesions received CK SRS. Lesions were present at the level of C1, C2, C3, C6-C7, T5, and T10-11. The median target volume was 0.72 cc (range: 0.32-2.54). A median marginal dose of 24 Gy was delivered to the tumors with a median of three fractions to a median isodose line of 80% (range: 78-81). LTC at the 24-month follow-up was 100%. PFS and OS were 27 months and 40 months, respectively. No adverse radiation effects were reported. Even though the treated spinal lesions remained stable, the number of new metastatic lesions had increased with progressive osseous and dural metastatic lesions within the cervical, thoracic, and lumbar spine at the last follow-up. SRS provides relatively good LTC for patients with ENB metastasizing to the spine, with no radiation-induced adverse events.

OBJECTIVE: To investigate the treatment outcome, visual outcome, and adverse effects of five-fraction stereotactic radiosurgery (SRS) to medium- and large-sized uveal melanoma with a non-invasive eye immobilization device.
METHODS: Medical records of 14 patients with uveal melanoma receiving SRS with a total dose of 50 Gy in five fractions from 2008 to 2017 were retrospectively reviewed. A non-invasive eye fixation device was used to achieve and monitor eye immobilization.
RESULTS: Local tumor control rates were 85.7% and 75.0% at 2 and 5 years, respectively. The average tumor diameter decreased significantly from 10.0 ± 3.21 mm to 8.36 ± 3.71 mm (p = 0.038) 15 months after SRS, while the average tumor thickness decreased significantly from 5.45 ± 2.21 mm to 4.34 ± 2.29 (p = 0.036) 21 months after SRS. The 5-year metastasis-free survival was 87.5%. The mean best-corrected visual acuity (BCVA) deteriorated from logMAR 0.296 at baseline to logMAR 1.112 at the last individual follow-up visits (p < 0.001). Adverse effects of SRS were comparable to those reported with proton-beam radiotherapy or Gamma knife therapy.
CONCLUSIONS: SRS combined with a non-invasive eye immobilization device is an effective and safe alternative eye-preserving treatment for medium- to large-sized uveal melanoma. BCVA at 3 months may be a predictor for BCVA at 1 year.

Synovial sarcoma (SS) is a rare and aggressive type of soft tissue sarcoma that commonly affects young adults. Metastasis in the spine is a rare complication, and the management of these lesions is challenging. Radiosurgery is an increasingly popular treatment option for spinal metastasis due to its ability to deliver high doses of radiation to the target volume with minimal exposure to surrounding healthy tissues. In this paper, we present two cases of SS with spinal metastasis that were treated with CyberKnife radiosurgery (CKRS). The first case was a 52-year-old female with a history of multiple thoracotomies and lobectomies for lung metastases, who was diagnosed with T6-T8 and T4 spinal metastasis. The second case was a 53-year-old female with Down syndrome, who was diagnosed with T12-L1 spinal metastasis. Both patients experienced an improvement in their symptoms following CKRS treatment and showed stable or decreasing lesion sizes on follow-up imaging. The progression-free survival (PFS) in the first case was 37 months and overall survival (OS) was 79 months. In the second case, the PFS was 12 months and OS was 18 months. These cases highlight the potential benefits of CKRS as a treatment option for SS with spinal metastasis and support its use in the management of this challenging condition.

Treatment options for renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVC-TT) are limited and carry substantial risks. Currently, there are no standard treatment options in the setting of recurrent or unresectable RCC with IVC-TT.
We report our experience of treating an IVC-TT RCC patient with stereotactic body radiation therapy (SBRT).
This 62-year-old gentleman presented renal cell carcinoma with IVC-TT and liver metastases. Initial treatment consisted of radical nephrectomy and thrombectomy followed by continuous sunitinib. At 3 months, he developed an unresectable IVC-TT recurrence. A fiducial marker was implanted into the IVC-TT by catheterization. New biopsies were performed at the same time, demonstrating a recurrence of the RCC. SBRT consisted of 5 fractions of 7 Gy to the IVC-TT with excellent initial tolerance. He subsequently received anti-PD1 therapy (nivolumab). At 4 years follow-up, he is doing well with no IVC-TT recurrence and no late toxicity.
SBRT appears to be a feasible and safe treatment for IVC-TT secondary to RCC in patients who are not candidates for surgery.

Self-shielding gyroscopic radiosurgery (GRS) represents a technical innovation in the field of stereotactic radiosurgery. GRS does not require a radiation vault and is optimized for radiosurgical treatments. Reports on its usage are limited. We describe the first clinical experience of GRS at our institution to assess the application of GRS in the treatment of cranial tumors. Moreover, we perform a dosimetric comparison to robotic radiosurgery (RRS) with vestibular schwannoma (VS) GRS patients.
Patients who were treated with GRS between July and November 2021 were included. Patient, tumor, and dosimetric characteristics were retrospectively summarized and analyzed.
Forty-one patients with 48 intracranial tumors were included. Tumor entities mostly comprised VS, brain metastases, and meningiomas. The median prescription dose and isodose line were 13.5 Gy and 50.0% for benign neoplasia versus 20 Gy and 60.0% for malignant tumors, respectively. The mean planning target volume was 1.5 cubic centimeters. All patients received a single-fraction treatment without encountering any technical setup difficulties. Treatment plan comparisons with RRS revealed comparable plan characteristics, dose gradients, and organs at risk doses. Significant differences were detected concerning the new conformity index and number of monitor units per treatment (both P < 0.01).
This case series provides more evidence on the usage of self-shielding GRS in the management of cranial tumors. Dosimetric comparisons for VS cases revealed mostly equivalent dosimetric characteristics to RRS. Further clinical and physical analyses for GRS are underway.