Stereotactic Body Radiotherapy - Current Indications.

BACKGROUND: Stereotactic body radiotherapy (SBRT) is used to treat localized tumor lesions and consists of applying high doses of radiation to a small number of fractions using specially equipped linear accelerators, modern immobilization devices, and imaging methods, which are considered special, advanced techniques in modern day radiotherapy. SBRT is a very well tolerated, non-invasive, short-term treatment that does not require hospitalization or any complicated preparation. Compared to standard radiotherapy techniques, SBRT allows, due to its precision, significantly higher doses to be applied to the target with less damage to surrounding healthy tissues. If dose constraints are not exceeded, the risk of damage to tissues and organs around the irradiated volume is reduced to minimum. The principle of SBRT is the application of ablative doses of radiation that cause necrosis of the irradiated tissue. PURPOSE: The aim of this review is to provide a basic overview of SBRT indications, radiation doses used, and potential side effects. It is not intended to be a detailed description of treatment itself (such as discussion of patient fixation systems, management of respiratory movements, or image guided strategies of treatment). This review also discusses rarer indications for SBRT, such as pancreatic carcinoma or hepatocellular carcinoma. CONCLUSION: Advances in image navigation, radiation planning, and dose application have enabled successful introduction of SBRT as a treatment regimen for many primary tumors and oligometastatic disease. If surgery is not possible or the patient refuses surgery, it is always reasonable to consider SBRT. SBRT has curative potential for the treatment of primary lung or prostate tumors. High-dose irradiation of oligometastases of various primary tumors can lead to long-term survival without disease symptoms, delay administration of toxic systemic therapies, and improve the quality of life of oncological patients. Key words radiotherapy - stereotactic body radiotherapy - review - ablative radiotherapy - lung cancer - prostate cancer - oligometastatic disease This work was supported in part by the Ministry of Health, Czech Republic - Conceptual Development of Research Organization (MMCI 00209805). The results of this research have been acquired within CEITEC 2020 (LQ1601) project with the financial contribution made by the Minis-try of Education, Youths and Sports of the Czech Republic within special support paid from the National Programme for Sustainability II funds. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 30. 10. 2018 Accepted: 4. 11. 2018.

Ablative dose stereotactic body radiation therapy for oligometastatic disease: a prospective single institution study.

Localized, metastasis-directed stereotactic body radiation therapy (SBRT) of oligometastatic disease (OD) is currently rapidly evolving standard of care in many institutions. Further reports of outcomes are required to strengthen the level of evidence in the absence of comparative trials evaluating different practical procedures. The aim of this prospective single institutional study is to analyse, in unselected cohort of patients from real-world clinical practice, the long-term survival, tumor control outcomes and safety of SBRT in OD (radical ablative radiotherapy with biological equivalent dose BED10>100 Gy). In addition to standard toxicity and survival parameters, we report unique outcomes as FFWD - Freedom from widespread dissemination, FFNT - Freedom from the need of subsequent treatment and functional survival with Karnofsky performance status higher than 70%. A total of 110 patients were prospectively evaluated, 60% and 40% were treated for lung and liver oligometastatic disease, respectively. No grade 3 or 4 acute toxicities (CTCAE) were reported. With median follow up of 22.2 months and 2-year overall survival of 88.3%, four patients (6.1%) experienced local progression in the lung SBRT cohort. In the liver SBRT cohort, median follow up was 33 months, 2-year overall survival was 68.5% and 11 patients (25%) experienced local and 36 (81.8%) distal progression. Higher BED10 of 150-170 Gy compared to 100-150 Gy was an independent positive prognostic factor for local progression-free survival for all patients with hazard ratio 0.25. This confirms SBRT ablative radiobiology effects to be independent of OD primary histology and location. The best outcomes in terms of FFNT were observed in the multivariable analysis of patients with 1-2 lung OD compared to both the liver OD cohort and patients with more than 2 lung metastases. Better FFNT in the liver SBRT cohort was observed in patients with 1-2 liver metastases and in patients whose liver OD was irradiated by higher BED10. In conclusion, SBRT is a suitable option for patients who are not surgical candidates; with approximately 30% of patients not requiring subsequent treatment 2 years after SBRT. We believe that this treatment represents a safe and effective option for oligometastatic involvement in patients with various primary tumors.

Utilization of Prognostic Indexes for Patients with Brain Metastases in Daily Radiotherapy Routine -  is the Complexity and Intricacy Still an Issue?

BACKGROUND: Many prognostic indexes are available for patients with brain metastases in order to estimate remaining lifetime before selection of appropriate treatment including palliative radiotherapy. Their routine utilization is often deprecated for their complexity. We developed a practical tool based on widely available spreadsheet editors for facilitation of daily clinical use of selected indexes (RPA, GPA and WBRT 30) and evaluated its usage for retrospective single institutional survival analysis of patients irradiated for brain metastases. PATIENTS AND METHODS: Spreadsheet platform was prepared and adjusted for automatic calculation of selected prognostic indexes after input of the relevant parameters. The consecutive series of newly diagnosed patients referred during 2011 to the palliative brain radiotherapy were analyzed, and real calculated survival parameters of individual subgroups of RPA, GPA and WBRT 30 were compared with estimated ones. Correlation of radiotherapy technique and estimated survival at the time of treatment indication was evaluated. RESULTS: Total of 121 patients (61% with multiple metastases) were irradiated with the majority undergoing whole brain radiotherapy. Median overall survival from the time of radiotherapy indication was 3.13 months. Non balanced distribution into individual scoring systems subgroups was observed with 8 (7%), 89 (73%) and 24 (20%) patients assigned to RPA 1, 2 and 3 subgroup, 3 (3%), 9 (7%), 57 (47%) and 52 (43%) patients assigned to GPA 3.5- 4, GPA 3.0, GPA 1.5- 2.5 and GPA 0- 1.0 subgroup and 10 (8%), 88 (73%) and 23 (19%) patients assigned to WBRT 30 subgroup D, B and A. Entire differences in overall survival between subgroups are significant among all three scoring systems. CONCLUSION: Routine calculation of available prognostic indexes is useful in decision making regarding the best radiotherapy of brain metastases, and their calculation is greatly facilitated by properly prepared widely available spreadsheet tools.

Volumetric modulated arc therapy for hippocampal-sparing radiotherapy in transformed low-grade glioma: A treatment planning case report.

Timing of radiotherapy for low-grade gliomas is still controversial due to concerns of possible adverse late effects. Prevention of possible late cognitive sequelae by hippocampal avoidance has shown promise in phase II trials. A patient with progressive low-grade glioma with gradual dedifferentiation into anaplastic astrocytoma is presented along with description of radiotherapy planning process attempting to spare the hippocampus. To our knowledge, this is the first described case using volumetric modulated arc technique to spare hippocampus during transformed low-grade glioma radiotherapy. Using modern intensity-modulated radiotherapy systems it is possible to selectively spare hippocampus together with other standard organs at risk. For selected patients, an attempt to spare hippocampus can be considered as long as other dose characteristics are not significantly compromised compared to standard treatment plan created without any effort to avoid hippocampus.

Cytotype distribution at a diploid-hexaploid contact zone in Aster amellus (Asteraceae).

BACKGROUND AND AIMS: The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. METHODS: Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4',6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. KEY RESULTS: The diploid-hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. CONCLUSIONS: The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to the current distributional patterns of the cytotypes of A. amellus.

Stereotactic body radiation therapy for colorectal cancer liver metastases; early results.

BACKGROUND: Stereotactic body radiation therapy (SBRT) is well feasible and effective method for treatment of colorectal cancer liver metastases. MATERIALS AND METHODS: From September 2009 to December 2011, 11 patients with 15 inoperable liver metastases of colorectal cancer were treated by SBRT using Varian Clinac iX linear accelerator. We treated 6 men and 5 women of age from 51 to 81 years (median 68). SBRT doses ranged from 40 to 56 Gy (median 54 Gy) and were administered in 3 to 8 fractions. RESULTS: Local control rates at 2, 4, 6, 9 and 12 months after completion of SBRT were 100%, 91%, 91%, 67% and 50%, respectively. Disease progression-free survival rates at 2, 4, 6, 9 and 12 months were 82%, 82%, 64%, 50% and 50%, respectively. Median follow-up was 15 months. No severe side effects were attributed to the therapy. CONCLUSION: Our study assessed the feasibility of SBRT in selected group of patients with 1 to 3 colorectal cancer liver metastases with no other treatment option. We achieved excellent local control and very moderate acute and late side effects. Distant metastases were the most common recurrence form after SBRT. SBRT demonstrated excellent local control and resulted in occasional long-term survivors without any serious side effects of therapy.

Saudi Arabic speech audiometry for children.

Phonetically balanced mono and disyllabic Classical Arabic word lists were chosen to construct a Saudi Arabic speech test for children. These words were taken from children's stories. They were first evaluated by primary and pre-school children in the urban and rural areas of the Province and then divided in eight subgroups of 10 words each. The articulation curves obtained from the children with this test material are similar in course and value to that of the German language using similar speech-test material under the same conditions.

Saudi Arabic speech audiometry.

Phonetically balanced monosyllabic classical Arabic word lists were chosen to construct a Saudi Arabic speech test. These words were taken from primary school books, daily newspapers and children's stories. They were first evaluated by our students for their familiarity and homogeneity and then divided into six sub-groups of 20 words each. The normal speech-audiometric curves obtained from our students (normally hearing subjects) with this material are similar to normal curves obtained with most European and American monosyllabic word lists. The threshold of intelligibility for our test material was also found to be similar to that of most foreign languages using monosyllabic word lists under the same conditions.