Radiotherapy for the treatment of cancer in companion animals is currently administered by using megavoltage X-ray machines. Because these machines are expensive, most animal hospitals do not perform radiotherapy. This study evaluated the ability of relatively inexpensive kilovoltage X-ray machines to treat companion animals. A simulation study based on a commercial treatment-planning system was performed for tumors of the brain (non-infectious meningoencephalitis), nasal cavity (malignant nasal tumors), forefoot (malignant muscular tumors), and abdomen (malignant intestinal tumors). The results of kilovoltage (300 kV and 450 kV) and megavoltage (6 MV) X-ray beams were compared. Whereas the 300 kV and 6 MV X-ray beams provided optimal radiation dose homogeneity and conformity, respectively, for brain tumors, the 6 MV X-rays provided optimal homogeneity and radiation conformity for nasal cavity, forefoot, and abdominal tumors. Although megavoltage X-ray beams provided better radiation dose distribution in most treated animals, the differences between megavoltage and kilovoltage X-ray beams were relatively small. The similar therapeutic effects of the kilovoltage and 6 MV X-ray beams suggest that kilovoltage X-ray beams may be effective alternatives to megavoltage X-ray beams in treating cancers in companion animals.
Abdomen ; Animals ; Brain ; Brain Neoplasms ; Friends ; Hospitals, Animal ; Humans ; Nasal Cavity ; Pets ; Radiotherapy ; Therapeutic Uses

Purpose: We evaluated the safety, feasibility, and early treatment outcomes of intraoperative radiotherapy (IORT) using a lowenergy X-ray source. Materials and Methods: Patients with resectable pancreatic cancer were enrolled in this single-institution, prospective, singlearm, phase II trial. Patients underwent surgery and IORT with 10 Gy prescribed at a 5-mm depth from the tumor bed using a 50 kV X-ray source (Intrabeam, Carl Zeiss). Six cycles of adjuvant gemcitabine-based chemotherapy were administered 8–12 weeks after surgery. Results: A total of 41 patients were included. Thirty-one patients (75.6%) underwent wide R0 resection, while 5 (12.2%) underwent R1 resection and 5 (12.2%) underwent narrow R0 resection (retroperitoneal margin <1 mm). Grade 3 postoperative complications were reported in only one patient (4.9%) who needed additional surgery due to ulcer perforation. At a median follow-up of 9 months, four patients showed local-only recurrence, nine had distant metastases, and two showed both local and distant recurrence. The 1-year local control rate was 76.4%. Conclusion Our preliminary report suggests that IORT is well-tolerated and feasible in patients with resectable pancreatic cancer. Further follow-up is needed to confirm the clinical benefits of IORT in terms of local control and overall survival.Trial Registration: Clinical trial registration No. (NCT03273374).

PURPOSE: To evaluate the clinical outcomes of patients who underwent radiation therapy with or without targeted molecular therapy for the treatment of spinal metastasis from renal cell carcinoma (RCC). MATERIALS AND METHODS: A total of 28 spinal metastatic lesions from RCC patients treated with radiotherapy between June 2009 and June 2015 were retrospectively reviewed. Thirteen lesions were treated concurrently with targeted molecular therapy (concurrent group) and 15 lesions were not (nonconcurrent group). Local control was defined as lack of radiographically evident local progression and neurological deterioration. RESULTS: At a median follow-up of 11 months (range, 2 to 58 months), the 1-year local progression-free rate (LPFR) was 67.0%. The patients with concurrent targeted molecular therapy showed significantly higher LPFR than those without (p = 0.019). After multivariate analysis, use of concurrent targeted molecular therapy showed a tendency towards improved LPFR (hazard ratio, 0.13; 95% confidence interval, 0.01 to 1.16). There was no difference in the incidence of systemic progression between concurrent and nonconcurrent groups. No grade ≥2 toxicities were observed during or after radiotherapy. CONCLUSION: Our study suggests the possibility that concurrent use of targeted molecular therapy during radiotherapy may improve LPFR. Further study with a large population is required to confirm these results.
Carcinoma, Renal Cell* ; Follow-Up Studies ; Humans ; Incidence ; Molecular Targeted Therapy* ; Multivariate Analysis ; Neoplasm Metastasis* ; Radiotherapy ; Retrospective Studies ; Treatment Outcome*