Lung stereotactic radiation therapy: Intercomparison of irradiation devices in terms of outcome and predictive factors

PURPOSE

To compare three different radiotherapy devices able to perform pulmonary stereotactic radiotherapy: CyberKnife® (CK), Helical Tomotherapy® (HT), and volumetric modulated arc therapy (VMAT). This study aims to define the patients' outcome in terms of SBRT efficacy and toxicities depending of the device choice.

MATERIALS AND METHODS

We retrospectively analyzed the clinical, radiological, and dosimetric data of patients treated with lung SBRT between 2016 and 2020 at Lausanne University Hospital, using the Chi² test for proportions, the t-test for means comparisons, the Kaplan-Meier method for survival, and the Log-rank test and Cox-regression for intergroups comparisons.

RESULTS

We identified 111 patients treated by either CK (59.9%), VMAT (38.0%), or HT (2.1%). Compared to other techniques, CK treated comparable gross tumor volume (GTV; 2.1 vs. 1.4cm³, P=0.84) with smaller planning treatment volume (PTV; 12.3 vs. 21.9cm³, P=0.013) and lower V5 (13.5 vs. 19.9cm³, P=0.002). Local control rates at 2years were not different whatever the irradiation device, respectively of 96.2% (range, 90.8-100) and 98.1% (range, 94.4-100), P=0.68. Toxicity incidence significantly increased with V5 value>17.2% (56.0 vs. 77.4%, P=0.021).

CONCLUSION

Compared to other SBRT techniques, CK treatments permitted to treat comparable GTV with reduced PTV and V5. Toxicity incidence was less frequent when reducing the V5. CK is particularly attractive in case of multiple courses of lung SBRT or lung reirradiation.

Steroid resistance in severe asthma: current mechanisms and future treatment

The disproportionate cost of treating asthmatic patients who do not respond to conventional anti-inflammatory therapies makes delineation of the mechanism for glucocorticoid resistance an important field of asthma research. Unbiased cluster analysis indicates that asthma is a syndrome with a number of distinct phenotypes and 5-10% of asthmatics fall into this category of relative glucocorticoid insensitivity. This sub-population is itself divided into smaller subsets which have different underlying mechanisms for this relative glucocorticoid resistance ranging from an inherited genetic basis to specific kinase signalling pathways triggered by exposure to environmental stressors such as cigarette smoking or infection. Whilst the underlying mechanisms are becoming better understood there remains a lack of effective novel therapies. However it is clear that relative glucocorticoid insensitive patients who are smokers should be encouraged to quit, thereby reducing their oxidant load. Novel treatments will consist of either developing new anti-inflammatory treatments targeting pathways aberrantly activated in these patients or of suppressing signalling pathways that attenuate glucocorticoid receptor function and thereby restoring glucocorticoid sensitivity. It will be important to uncover non-invasive biomarkers for aberrant pathway activation and for discerning which components of glucocorticoid receptor activation are abnormal if future treatments are to be tailored to address these specific issues. Conventional combination therapies will continue to be used in the near future but additional add-on treatments using drugs directed against aberrantly expressed inflammatory pathways or mediators along with an inhaled glucocorticoid are likely to prove the most effective new therapies in the future.

Classification of canine malignant lymphomas according to the World Health Organization criteria

A study was carried out to test the accuracy and consistency of veterinary pathologists, not specialists in hematopathology, in applying the World Health Organization (WHO) system of classification of canine lymphomas. This study represents an initiative of the ACVP Oncology Committee, and the classification has been endorsed by the World Small Animal Veterinary Association (WASVA). Tissue biopsies from cases of canine lymphoma were received from veterinary oncologists, and a study by pathologists given only signalment was carried out on 300 cases. Twenty pathologists reviewed these 300 cases with each required to choose a diagnosis from a list of 43 B and T cell lymphomas. Three of the 20 were hematopathologists who determined the consensus diagnosis for each case. The 17 who formed the test group were experienced but not specialists in hematopathology, and most were diplomates of the American or European Colleges of Veterinary Pathology. The overall accuracy of the 17 pathologists on the 300 cases was 83%. When the analysis was limited to the 6 most common diagnoses, containing 80% of all cases, accuracy rose to 87%. In a test of reproducibility enabled by reintroducing 5% of cases entered under a different identity, the overall agreement between the first and second diagnosis ranged from 40 to 87%. The statistical review included 43,000 data points for each of the 20 pathologists.

Inflammatory biomarkers in airways of patients with severe asthma compared with non-severe asthma

BACKGROUND

About 5-10% of patients with asthma suffer from poorly-controlled disease despite corticosteroid (CS) therapy.

OBJECTIVE

We determined whether there were any differences in inflammatory biomarkers between severe and non-severe asthma patients.

METHODS

Nineteen severe and 20 non-severe asthma patients were recruited and underwent collection of induced sputum, bronchoalveolar lavage (BAL) fluid and bronchial biopsies.

RESULTS

Biopsy results showed no differences in eosinophils (major basic protein positive), neutrophils, macrophages, T cells and mast cells in the bronchial submucosa. However, subbasement membrane (SBM) thickness and smooth muscle area were increased in the biopsies. No significant differences were observed in the induced sputum inflammatory cells. In BAL fluid, there was a significant increase in neutrophils but a significant decrease in macrophages. Eosinophil counts were non-significantly increased threefold in both sputum and BAL in severe asthma. Levels of IL-8 and IL-13 in sputum supernatants were similar in both groups of asthma patients. There was a significant inverse correlation between post-bronchodilator forced expiratory volume in 1 s and provocative concentration of methacholine causing a 20% fall in FEV(1) with SBM thickness.

CONCLUSION

Differences in inflammatory cells were observed mainly in terms of increased neutrophils and reduction in macrophage numbers in BAL fluid with a trend towards increased eosinophils in severe asthma compared with non-severe asthma. However, the most notable features are the increase in features of airway wall remodelling of SBM thickness and smooth muscle area.

Functional specialization in rhesus monkey auditory cortex

Neurons in the lateral belt areas of rhesus monkey auditory cortex prefer complex sounds to pure tones, but functional specializations of these multiple maps in the superior temporal region have not been determined. We tested the specificity of neurons in the lateral belt with species-specific communication calls presented at different azimuth positions. We found that neurons in the anterior belt are more selective for the type of call, whereas neurons in the caudal belt consistently show the greatest spatial selectivity. These results suggest that cortical processing of auditory spatial and pattern information is performed in specialized streams rather than one homogeneously distributed system.