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A survey of stereotactic radiation therapy in veterinary medicine.

ABSTRACT: Radiotherapy plays an important role in curative and palliative cancer treatment. As a novel radiation delivery technique, stereotactic radiotherapy utilizes three-dimensional-conformal treatment planning, high-precision beam delivery technology, and patient specific position verification to target tumors, often in one to five high-dose fractions. Currently, there is no consensus about best stereotactic radiotherapy practices in veterinary radiotherapy. The objective of this study was to document the breadth of perspectives, techniques, and applications of stereotactic radiotherapy in veterinary medicine. We conducted an online survey of American College of Veterinary Radiology members specializing in radiation oncology to assess how, when, and why stereotactic radiotherapy is being used. Both stereotactic radiotherapy users and nonusers completed the survey. The overall response and survey completion rates were 54% (67/123) and 87% (58/67), respectively. Overall, 55% of respondents reported providing stereotactic radiotherapy at their facility, with a median of 4.5 canine cases and one feline case per month. Delivery methods included C-arm linear accelerator with multi-leaf collimator, helical tomotherapy, and CyberKnife. Nonpituitary intracranial tumors, pituitary tumors, and sinonasal tumors were the most common cancers treated using stereotactic radiotherapy in both species. The most common fractionation scheme was three fractions of 10 Gy/fraction. The results of this survey suggest common availability of stereotactic radiotherapy in veterinary radiation facilities. These results provide valuable information regarding current stereotactic radiotherapy practices in veterinary medicine, and may provide an initial step toward standardizing methods and establishing consensus guidelines.

SUBMITTER: Dunfield EM

PROVIDER: S-EPMC6218303 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature

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A survey of stereotactic radiation therapy in veterinary medicine.

Dunfield Elizabeth M EM Turek Michelle M MM Buhr Kevin A KA Christensen Neil I NI

Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association 20180730 6

Radiotherapy plays an important role in curative and palliative cancer treatment. As a novel radiation delivery technique, stereotactic radiotherapy utilizes three-dimensional-conformal treatment planning, high-precision beam delivery technology, and patient specific position verification to target tumors, often in one to five high-dose fractions. Currently, there is no consensus about best stereotactic radiotherapy practices in veterinary radiotherapy. The objective of this study was to documen ...[more]

PMID: 30062728

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Project description:OBJECTIVE Although postoperative stereotactic body radiation therapy (SBRT) for spinal metastases is increasingly performed, few guidelines exist for this application. The purpose of this study is to develop consensus guidelines to promote safe and effective treatment for patients with spinal metastases. METHODS Fifteen radiation oncologists and 5 neurosurgeons, representing 19 centers in 4 countries and having a collective experience of more than 1300 postoperative spine SBRT cases, completed a 19-question survey about postoperative spine SBRT practice. Responses were defined as follows: 1) consensus: selected by ≥ 75% of respondents; 2) predominant: selected by 50% of respondents or more; and 3) controversial: no single response selected by a majority of respondents. RESULTS Consensus treatment indications included: radioresistant primary, 1-2 levels of adjacent disease, and previous radiation therapy. Contraindications included: involvement of more than 3 contiguous vertebral bodies, ASIA Grade A status (complete spinal cord injury without preservation of motor or sensory function), and postoperative Bilsky Grade 3 residual (cord compression without any CSF around the cord). For treatment planning, co-registration of the preoperative MRI and postoperative T1-weighted MRI (with or without gadolinium) and delineation of the cord on the T2-weighted MRI (and/or CT myelogram in cases of significant hardware artifact) were predominant. Consensus GTV (gross tumor volume) was the postoperative residual tumor based on MRI. Predominant CTV (clinical tumor volume) practice was to include the postoperative bed defined as the entire extent of preoperative tumor, the relevant anatomical compartment and any residual disease. Consensus was achieved with respect to not including the surgical hardware and incision in the CTV. PTV (planning tumor volume) expansion was controversial, ranging from 0 to 2 mm. The spinal cord avoidance structure was predominantly the true cord. Circumferential treatment of the epidural space and margin for paraspinal extension was controversial. Prescription doses and spinal cord tolerances based on clinical scenario, neurological compromise, and prior overlapping treatments were controversial, but reasonable ranges are presented. Fifty percent of those surveyed practiced an integrated boost to areas of residual tumor and density override for hardware within the beam path. Acceptable PTV coverage was controversial, but consensus was achieved with respect to compromising coverage to meet cord constraint and fractionation to improve coverage while meeting cord constraint. CONCLUSIONS The consensus by spinal radiosurgery experts suggests that postoperative SBRT is indicated for radioresistant primary lesions, disease confined to 1-2 vertebral levels, and/or prior overlapping radiotherapy. The GTV is the postoperative residual tumor, and the CTV is the postoperative bed defined as the entire extent of preoperative tumor and anatomical compartment plus residual disease. Hardware and scar do not need to be included in CTV. While predominant agreement was reached about treatment planning and definition of organs at risk, future investigation will be critical in better understanding areas of controversy, including whether circumferential treatment of the epidural space is necessary, management of paraspinal extension, and the optimal dose fractionation schedules.

Project description:Purpose:Patients with oligometastatic colorectal cancer have demonstrated excellent clinical outcomes with surgical resection of hepatic and pulmonary metastases. Stereotactic ablative radiation therapy (SABR) has emerged as an alternative local therapy for nonsurgical candidates. Herein, we report the oncologic and patient-reported quality-of-life (PR-QoL) outcomes for a subset of patients with oligometastatic colorectal cancer who were treated in a prospective phase 2 multicenter clinical trial. Methods and materials:Patients with a pathologically proven diagnosis of oligometastatic colorectal cancer were enrolled as part of a prospective study. SABR dose and fractionation schedules were dependent on the lesion location and size. Patient follow-up occurred 6 weeks after completion of SABR and at 3-month intervals for the following 3 years. Patients received the Functional Assessment of Cancer Therapy-General questionnaire at baseline and at each follow-up visit to assess PR-QoL. The total Functional Assessment of Cancer Therapy-General questionnaire scores were compared with those from baseline using the Wilcoxon signed rank test. Overall survival, local progression-free survival (PFS), and distant PFS were calculated using the Kaplan-Meier estimation to the date of the last follow-up visit/death or local/distant failure. Results:A total of 31 patients with oligometastatic colorectal cancer with 1 (71.0%), 2 (16.1%), 3 (3.2%), 4 (3.2%), or 5 (6.5%) metastatic lesions were identified. After a median follow-up time of 50.1 months, the median OS from the time of completion of the SABR was 53.9 months (95% confidence interval, 23.2-84.6), and the 5-year OS, local PFS, and distant PFS were 45%, 83%, and 27%, respectively. Acute grade 2+ toxicity was 9.7% (pain, nausea, fatigue) and late grade 3+ toxicity (small bowel obstruction) was 3.2% with no significant change in PR-QoL in the year after SABR. Conclusions:This subset analysis of a prospective phase 2 study demonstrates that SABR is a safe and effective treatment option for patients with unresectable oligometastic colorectal cancer. In addition, SABR of oligometastatic disease preserves PR-QoL.

Project description:Aim:Radiation therapy has been proven “safe and effective” in the management of colorectal cancer liver metastases, especially for oligometastases. However, to date, there is no consensus on optimal prescribed doses or dose fraction schemes. The current study was conducted to investigate the effectiveness and safety of 2 different radiation therapy methods, conventional conformal radiation therapy and stereotactic body radiation therapy, in the treatment of limited colorectal cancer liver metastases.Methods:From December 2011 to December 2016, twenty-six patients with colorectal cancer having postoperative liver metastases (?3) who were being treated with radiation therapy, either conventional conformal radiation therapy (50 Gy in 25 fractions) or stereotactic body radiation therapy (50 Gy in 10 fractions), were selected for this study. Overall survival and local control survival were analyzed by log-rank and Cox regression methods.Results:Radiation therapy delivered to each of the 26 patients with a total of 50 liver lesions. Conformal radiation therapy was delivered to 32 lesions in a total of 15 patients. Stereotactic body radiation therapy was delivered to 18 lesions in a total of 11 patients. Median follow-up was 13 months. Three-year overall survival and local control survival were 0% and 38.5%, 20.5%, and 53.0%, respectively, for the conformal radiation therapy and stereotactic body radiation therapy groups. The slightly better overall survival and local control survival in the stereotactic body radiation therapy group in comparison to the conformal radiation therapy group (P = .323 and .297) is insignificant. There were no differences in grade 3 hepatic toxicity between the 2 groups. Eastern Cooperative Oncology Group performance status and the number of liver lesions were significant prognostic factors in both univariate and multivariate analyses.Conclusions:Noninvasive radiation therapy provides satisfactory survival benefit for limited colorectal cancer liver metastases without intolerable toxicity and is therefore especially suitable for those elderly patients with poor performance status. Furthermore, stereotactic body radiation therapy with a higher biological equivalent dose and an abbreviated course of treatment has been shown to provide a better outcome than conventional conformal radiation therapy.

Project description:PurposeStereotactic body radiation therapy (SBRT) is a promising treatment modality for locally advanced pancreatic cancer (LAPC). We evaluated the clinical outcomes of SBRT in patients with LAPC.Patients and methodsWe retrospectively analyzed the medical records of patients with LAPC who underwent SBRT at our institution between April 2011 and July 2016. Fiducial markers were implanted using endoscopic ultrasound guidance one week prior to 4-dimensional computed tomography (CT) simulation and daily cone beam CT was used for image guidance. Patients received volumetric modulated arc therapy or intensity modulated radiotherapy using respiratory gating technique. A median dose of 28 Gy (range, 24-36 Gy) was given over four consecutive fractions delivered within one week. Survival outcomes including freedom from local disease progression (FFLP), progression-free survival (PFS), and overall survival (OS) were analyzed. Acute and late toxicities related to SBRT were assessed.ResultsA total of 95 patients with LAPC were analyzed, 52 of which (54.7%) had pancreatic head cancers. Most (94.7%) had received gemcitabine-based chemotherapy. The 1-year FFLP rate was 80.1%. Median OS and PFS were 16.7 months and 10.2 months, respectively; the 1-year OS and PFS rates were 67.4% and 42.9%, respectively. Among 79 patients who experienced failure, the sites of first failures were isolated local progressions in 12 patients (15.2%), distant metastasis in 55 patients (69.6%), and both in 12 patients (15.2%). Seven patients (7.4%) were able to undergo surgical resection after SBRT and four had margin-negative resections. Three patients (3.2%) had grade 3 nausea/vomiting during SBRT, and late grade 3 toxicity was observed in another three patients.ConclusionsLAPC patients who received chemotherapy and SBRT had favorable FFLP and OS with minimal treatment-related toxicity. The most common pattern of failure was distant metastasis, which warrants further studies on the optimal scheme of chemotherapy and SBRT.

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A survey of stereotactic radiation therapy in veterinary medicine.

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A survey of stereotactic radiation therapy in veterinary medicine.

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