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.

Leptomeningeal carcinomatosis (LMC) from renal cell carcinoma (RCC) is rare. There is no established treatment strategy for LMC, and the prognosis is extremely poor. We describe a case of LMC from RCC treated with local CyberKnife radiotherapy (CKR) and systemic therapy with pazopanib. The patient was a 63-year-old man with brain metastases from right RCC. Surgery and CKR were performed for the brain metastases, and the lesions were subsequently controlled. The patient developed isolated lesions in the pituitary stalk, right internal auditory canal, left ventricular choroid plexus (CP), left facial nerve, and medulla oblongata after the surgery and CKR for brain metastases. We diagnosed LMC and treated the patient with systemic therapy with pazopanib. We performed local therapy with CKR for lesions of the pituitary stalk, right internal auditory canal, left facial nerve, and medulla oblongata. The CP lesion was not treated with CKR because the lesion tended to shrink after systemic therapy with pazopanib. There were no symptoms due to LMC until the end of life and no adverse events due to CKR. Ten years and five months after the nephrectomy for RCC, one year and four months after the initial CKR for brain metastases, and nine months after the diagnosis of LMC, the patient died due to pleural effusion from lung metastases. Our case suggests that CKR combined with pazopanib may be effective as a palliative treatment for LMC from RCC.

Diffuse large B-cell lymphoma (DLBCL) of the skull is rare, and there are no reports of treatment using CyberKnife (CK). Here, we report the case of a patient with skull DLBCL treated with low-dose CK radiotherapy (CKR), resulting in effective local control. The patient was a 75-year-old man who was initially diagnosed with multiple skull metastases (frontal, occipital, right orbital bones) from renal pelvic cancer. We initially created a CKR treatment plan for the frontal bone lesion with a marginal dose of 35 Gy and a maximum of 64.8 Gy in five fractions every other day. Because the frontal bone lesion shrank rapidly from the start of the treatment, we completed CKR with a marginal dose of 21 Gy and a maximum of 38.9 Gy in three fractions over five days. At six weeks after CKR, the MRI showed complete resolution of not only the frontal bone lesion but also the occipital and orbital bone lesions that we did not directly target for irradiation. The maximum doses irradiated to the occipital and orbital bone lesions were 0.31 Gy and 0.34 Gy. Because of the marked shrinkage of the skull lesions, we suspected that the patient had a radiosensitive neoplastic disease. FDG-PET/CT revealed multiple lymph nodes and bone metastases. The patient underwent a scrotal biopsy, and the histologic diagnosis was DLBCL. The patient subsequently received chemotherapy for DLBCL. Ten months after CKR and six months after the start of chemotherapy for DLBCL, the patient died due to gastrointestinal bleeding. The skull lesions were well-controlled locally without adverse events due to CKR until the end of the life. Our present case suggests the importance of diagnosis and the effectiveness of low-dose CKR in the skull DLBCL.

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.

OBJECTIVE: The purpose of this study was to evaluate the safety and feasibility of transarterial fiducial marker implantation for CyberKnife radiotherapy to treat locally advanced pancreatic cancer.
METHODS: Fifteen pancreatic cancer patients were enrolled for transarterial marker implantation. Embolization platinum coils were implanted as a fiducial marker within 20 mm of the cancer edge, and preferably within 3 mm. The technical success of the implantation was defined as implantation of at least one fiducial marker within 20 mm of the target tumor. Irradiation was performed using the CyberKnife system.
RESULTS: For 14 of 15 patients, transarterial implantation was successfully performed, and for 13 of 14 patients, the tracking marker was implanted within 3 mm of the cancer. Tracking instability was observed in two patients, but irradiation was accomplished in all 14 patients. No major complications caused by the implantation procedure were observed. The median overall survival after irradiation was 13.8 months, and the 1- and 2-years survival rates were 62.9% and 32.3%, respectively.
CONCLUSIONS: Transarterial fiducial marker implantation for pancreatic cancer can be safely performed for tracking, and it will be a valuable alternative approach to percutaneous fiducial marker implantation.

OBJECTIVE: To assess the safety and efficacy of CyberKnife® radiotherapy (CKRT) for the treatment of olfactory groove meningiomas (OGMs).
METHODS: A retrospective review was performed of 13 patients with OGM treated with CKRT from September 2005 to May 2018 at our institution. Nine patients were treated primarily with CKRT, 3 for residual disease following resection, and 1 for disease recurrence.
RESULTS: Five patients were treated with stereotactic radiosurgery (SRS), 6 with hypofractionated stereotactic radiotherapy (HSRT), and 2 with fractionated stereotactic radiotherapy (FSRT). The median tumor volume was 8.12 cm3. The median prescribed dose was 14.8 Gy for SRS, 27.3 Gy for HSRT, and 50.2 Gy for FSRT. The median maximal dose delivered was 32.27 Gy. Median post treatment follow-up was 48 months. Twelve of 13 patients yielded a 100% regional control rate with a median tumor volume reduction of 31.7%. Six of the 12 patients had reduced tumor volumes while the other 6 had no changes. The thirteenth patient had significant radiation-induced edema requiring surgical decompression. Twelve patients were alive and neurologically stable at the time of the review. One patient died from pneumonia unrelated to his CKRT treatment.
CONCLUSIONS: CKRT appears to be safe and effective for the treatment of OGMs.