JS09.6.A Low incidence of radiation-induced brain lesions and stable QoL following proton irradiation for CNS and Skull Base tumors- results from the prospective MedAustron register REGI-MA-002015

Background

Irradiation of intracranial tumors may induce endothelial damage in the surrounding normal brain tissues, resulting in an increase of capillary permeability. These changes can be depicted on magnetic resonance imaging (MRI) as a new contrast medium uptake - not associated with tumor. Radiation-induced brain lesions (RIBL) occur after photon as well as proton irradiation. This study evaluated the incidence of RIBL after proton irradiation and their impact on Quality of Life (QoL).

Material and Methods

421 patients treated between 01/2017 and 06/2021 were included. All patients participated in a prospective registry study (ClinicalTrials.gov Identifier: NCT03049072). Follow-up evaluations including MRIs were at 3,6,12 months after treatment completion and annually thereafter. QoL parameters were assessed by EORTC-CTC30 and BN20 questionnaires.

Results

48.9% (n=206) patients received therapy for intracranial non-CNS tumors (meningioma, pituitary adenoma, and other), 26.8% (n=113) for head and neck cancer with skull base involvement, 14.5% (n=61) for primary CNS tumors and 9.7% (n=41) for skull base tumor. Median follow-up was 24 months (range 6-54 ), 352 (86%) patients had proton therapy as primary treatment, 59 (14%) had salvage treatment with proton re-irradiation (ReRT). Median prescribed dose was 58.5 Gy (RBE) (range 40-78 Gy (RBE)), median D1% of brain tissue was 54.3 Gy (RBE) (range 30-76 Gy RBE). Local control and overall survival were 91% and 95% at 2 years. The cumulative RIBL incidence was 15.0% (n=63), with significantly lower occurrence in the primary RT group vs. the ReRT group (12.9% vs. 27.1%; p<0.001). According to Grade, the distribution was 10.5% (n=44) Grade I (asymptomatic, MRT finding only), Grade II RIBL, 13 (3.1%) (moderate symptoms) (grade 2) and 1,4% (n=6) developed Grade 3 toxicity. Actuarial 2-year RIBL incidence was 18.2% (95%CI: 14.1-23.2) for the all Grades and the entire, 15.7% (95%CI: 11.6-21) following primary radiation and 34.2% (95%CI: 21.9-50.9) after ReRT. All RIBL developed outside the residual tumor, but inside the Planning Target Volume (PTV), median D1% was 60.3Gy (RBE) (range 46.1- 122.3 Gy(RBE)), median time to development was 11.8 months (range 2.7-37 months) in the total cohort, for primary RT 14.2mo (4.3mo -37.1mo) and 6.0mo (2.7mo -19.3mo) following ReRT. At the time of analysis 26 of the 63 RIBL had resolved (41.3%). General QoL was not compromised. In a matched-pair analysis of 54/50 patients with/without RIBL, only at the 12 month a significant difference in the global health score in favour of non-RIBL patients was observed. At 24 months the score for RIBL patients improved without difference between the groups.

Conclusion

Overall incidence of RIBL after proton radiotherapy is very low - even for skull base tumors requiring high total doses and it had no significant negative impact on long term QoL.

P03.06.B Proton irradiation (PT) for benign meningiomas, Grade I clinical experience of the first 100 patients from REGI-MA-002015

Background

Meningiomas are the most common CNS tumors and the majority is regarded as benign. However, a subset of patients presents with complex tumors involving several anatomic compartments of the skull base - eluding any concepts of gross total resection. Proton therapy (PT) is applied as definitive treatment for primary or recurrent disease or postoperatively following subtotal resection. We report on the first 100 adult patients treated with PT at MedAustron.

Material and Methods

All patients were enrolled in a prospective registry trial (ClinicalTrials.gov Identifier: NCT03049072). Target volume definition was based on CT, MR and DOTA-PET/CT. PT treatment plans were generated by applying a Simultaneous Integrated Boost (SIB) concept with the Single Field-optimisation method and utilizing 2-4 beams per plan with a beam spacing of >30°. Prescribed doses to PTV1 were 50.49Gy_RBE at 1.87Gy_RBE/fr and 54.0Gy_RBE at 2.0Gy_RBE/fr to PTV2 in overall 27 fractions. Follow up status was assessed by MRI at 6, 12 months and annually thereafter, side effects were assessed using CTCAE v4.0. and quality of life (QoL) using EORTC-CTC30 and BN20 questionnaires. The scores entered by the patients were added and normalized to 0-100 scale according to previously described protocols.

Results

Between 08/2017 and 04/2021, 100 patients were treated, 22% (n=22) male and 78% (n=78) female patients. Median age at therapy was 54a (25a-82a). In 57% (n=57) PT was the definitive treatment (no resection or surgery >12 mo prior to PT). 43% (n=43) underwent postoperative PT with at least one surgery (range 1-3), and median time from last resection to start of PT of 6mo (3mo-11mo). 89% (n=89) meningiomas were located in the skull base with involvement of multiple anatomic compartments. The median GTV size was 24cc (1cc-226cc) and the median CTV 41cc (2cc-352cc), respectively. At median follow-up of 31.1 months (range 6.6-51.6), 2 local in-field failures were observed (both patients treated postoperatively) resulting in disease-specific survival of 100% and local control of 98% at 3 years, respectively. No > Grade 2 acute toxicity was observed. During follow-up two Grade 3 toxicities occurred: One patient developed symptomatic radiation induced brain lesion (RIBL) which resolved within 12 month; one patient was hospitalized for new onset of epilepsy without corresponding radiographic findings. 9% (n=9) developed G1/G2 RIBL, which resolved spontaneously. The general QoL including the global health status and all functioning domains remained stable and did not decrease significantly following PT.

Conclusion

First clinical data demonstrate that PT based on a SIB concept is a safe and efficient treatment of anatomically complex, low grade meningiomas. Acute and late toxicity incidences in our series were low with excellent, prospectively assessed preservation of QoL.

Complement activation induces excessive T cell cytotoxicity in severe COVID-19

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16+ T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16+ T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16+ T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16+ cytotoxic T cells. Proportions of activated CD16+ T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.

Severe COVID-19 Is Marked by a Dysregulated Myeloid Cell Compartment

Coronavirus disease 2019 (COVID-19) is a mild to moderate respiratory tract infection, however, a subset of patients progress to severe disease and respiratory failure. The mechanism of protective immunity in mild forms and the pathogenesis of severe COVID-19 associated with increased neutrophil counts and dysregulated immune responses remain unclear. In a dual-center, two-cohort study, we combined single-cell RNA-sequencing and single-cell proteomics of whole-blood and peripheral-blood mononuclear cells to determine changes in immune cell composition and activation in mild versus severe COVID-19 (242 samples from 109 individuals) over time. HLA-DRhiCD11chi inflammatory monocytes with an interferon-stimulated gene signature were elevated in mild COVID-19. Severe COVID-19 was marked by occurrence of neutrophil precursors, as evidence of emergency myelopoiesis, dysfunctional mature neutrophils, and HLA-DRlo monocytes. Our study provides detailed insights into the systemic immune response to SARS-CoV-2 infection and reveals profound alterations in the myeloid cell compartment associated with severe COVID-19.

SARS-CoV-2-reactive T cells in healthy donors and patients with COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the rapidly unfolding coronavirus disease 2019 (COVID-19) pandemic^1,2. Clinical manifestations of COVID-19 vary, ranging from asymptomatic infection to respiratory failure. The mechanisms that determine such variable outcomes remain unresolved. Here we investigated CD4⁺ T cells that are reactive against the spike glycoprotein of SARS-CoV-2 in the peripheral blood of patients with COVID-19 and SARS-CoV-2-unexposed healthy donors. We detected spike-reactive CD4⁺ T cells not only in 83% of patients with COVID-19 but also in 35% of healthy donors. Spike-reactive CD4⁺ T cells in healthy donors were primarily active against C-terminal epitopes in the spike protein, which show a higher homology to spike glycoproteins of human endemic coronaviruses, compared with N-terminal epitopes. Spike-protein-reactive T cell lines generated from SARS-CoV-2-naive healthy donors responded similarly to the C-terminal region of the spike proteins of the human endemic coronaviruses 229E and OC43, as well as that of SARS-CoV-2. This results indicate that spike-protein cross-reactive T cells are present, which were probably generated during previous encounters with endemic coronaviruses. The effect of pre-existing SARS-CoV-2 cross-reactive T cells on clinical outcomes remains to be determined in larger cohorts. However, the presence of spike-protein cross-reactive T cells in a considerable fraction of the general population may affect the dynamics of the current pandemic, and has important implications for the design and analysis of upcoming trials investigating COVID-19 vaccines.

Innate sensors that regulate vaccine responses

Pattern recognition receptors (PRRs) control elemental functions of antigen presenting cells (APCs) and critically shape adaptive immune responses. Wielding a natural adjuvanticity, live attenuated vaccines elicit exceptionally efficient and durable immunity. Commonly used vaccine adjuvants target individual PRRs or bolster the immunogenicity of vaccines via indirect mechanisms of inflammation. Here, we review the impact of innate sensors on immune responses to live attenuated vaccines and commonly used vaccine adjuvants, with a focus on human vaccine responses. We discuss the unique potential of microbial nucleic acids and their corresponding sensing receptors to mimic live attenuated vaccines and promote protective immunity.

[Treatment planning with functional MRI]

CLINICAL/METHODICAL ISSUE

The aim of magnetic resonance imaging (MRI) guided radiotherapy is high precision in treatment delivery. With new developments it is possible to focus the high dose irradiation on the tumor while sparing the surrounding tissue. The achievements in precision of the treatment planning and delivery warrant equally precise tumor definition.

STANDARD RADIOLOGICAL METHODS

In conventional radiation therapy it is necessary to carry out a planning computed tomography (CT). For many tumors there is also need for an additional morphological MRI because of more accurate tumor definition. In standard radiotherapy the tumor volume is irradiated with a homogeneous dose.

METHODICAL INNOVATIONS

The aim of functional multiparametric MRI is to visualize and quantify biological, physiological and pathological processes at the cellular and molecular levels. Based on this information it is possible to elucidate tumor biology and identify subvolumes of more aggressive behavior. They are often radiotherapy-resistant, leading to tumor recurrence thus requiring further dose escalation. The concept of inhomogeneous tumor irradiation according to its biological behavior is called dose painting.

PERFORMANCE

Dose painting is technically feasible. The expected clinical benefit is motivated by selective treatment adaptations based on biological tumor characteristics. Tumors show variable response to therapy underlining the need for individual treatment plans. This approach may lead not only to higher local control but also to better sparing of normal surrounding tissue.

ACHIEVEMENTS

With the clinical implementation of dose painting, improvements in the therapeutic outcome can be expected.

PRACTICAL RECOMMENDATIONS

Due to the existing technical challenges, extensive collaboration between radiation oncologists, radiologists, medical physicists and radiation biologists is needed.

Residual tumour volumes and grey zones after external beam radiotherapy (with or without chemotherapy) in cervical cancer patients. A low-field MRI study

BACKGROUND

Grey zones, which are defined as tissue with intermediate signal intensity in the area of primary hyperintense tumour extension, can be seen during radiation with or without chemotherapy on the T2-weighted MRI in patients with cervical cancer. The purpose of this study was to systematically measure the tumour volume at the time of diagnosis and the residual tumour volume at the time of brachytherapy without and with consideration of the grey zones and to estimate tumour regression during external beam radiotherapy (EBRT).

MATERIAL AND METHODS

T2-weighted MRI datasets of 175 patients with locally advanced cervical cancer (FIGO stage IB-IVA), who underwent combined external beam radiotherapy and brachytherapy with or without concomitant chemotherapy were available for this study. The gross tumour volume at the time of diagnosis (GTV(init)) and at the time of first brachytherapy without (GTV(res)) and with (GTV(res)+ GZ) consideration of grey zones were measured for each patient. A descriptive statistical analysis was performed and tumour regression rates without (R) and with consideration of grey zones (R(GZ)) were calculated. Further, the role of prognostic factors on GTV(init), GTV(res), GTV(res)+ GZ and tumour regression rates was investigated.

RESULTS

The median GTV(init), GTV(res), GTV(res)+ GZ in all patients were 44.4 cm(3), 8.2 cm(3), 20.3 cm(3), respectively. The median R was 78.5% and the median R(GZ) was 50.1%. The histology and FIGO staging showed a significant impact on GTV(init), GTV(res) and GTV(res)+ GZ.

CONCLUSION

Grey zones represent a substantial proportion of the residual tumour volume at the time of brachytherapy. Differentiation of high signal intensity mass and surrounding intermediate signal intensity grey zones may be reasonable.

Pathogen-triggered activation of plasmacytoid dendritic cells induces IL-10-producing B cells in response to Staphylococcus aureus

Induction of polyclonal B cell activation is a phenomenon observed in many types of infection, but its immunological relevance is unclear. In this study we show that staphylococcal protein A induces T cell-independent human B cell proliferation by enabling uptake of TLR-stimulating nucleic acids via the V(H)3(+) BCR. We further demonstrate that Staphylococcus aureus strains with high surface protein A expression concomitantly trigger activation of human plasmacytoid dendritic cells (pDC). Sensitivity to chloroquine, cathepsin B inhibition, and a G-rich inhibitory oligodeoxynucleotide supports the involvement of TLR9 in this context. We then identify pDC as essential cellular mediators of B cell proliferation and Ig production in response to surface protein A-bearing S. aureus. The in vivo relevancy of these findings is confirmed in a human PBMC Nod/scid(Prkdc)/γc(-/-) mouse model. Finally, we demonstrate that co-operation of pDC and B cells enhances B cell-derived IL-10 production, a cytokine associated with immunosuppression and induction of IgG4, an isotype frequently dominating the IgG response to S. aureus. IL-10 release is partially dependent on TLR2-active lipoproteins, a hallmark of the Staphylococcus species. Collectively, our data suggest that S. aureus exploits pDC and TLR to establish B cell-mediated immune tolerance.

HFE genotyping demonstrates a significant incidence of hemochromatosis in undifferentiated arthritis

OBJECTIVE

Hereditary hemochromatosis is a common autosomal recessive disorder of iron metabolism. Among Northern Europeans the carrier frequency is estimated to be 1 in 10, while up to 1 in 200 is affected by the disease. Arthropathy is one early clinical manifestation of this disease, but the articular features are often misdiagnosed. In this study the two frequent mutations of the HLA-linked hemochromatosis gene (HFE) were investigated in a rheumatology clinic population.

METHODS

Two hundred and six consecutive patients (mean age 57.7 years; 38 male/168 female) attending a rheumatology clinic over a period of 14 months were screened for HFE mutations (C282Y and H63D). All standard diagnostic procedures were used to identify the aetiology of the arthropathy. Mutations were evaluated by separation on PAGE of digested PCR amplificates of DNA (by SnapI and Bcl-I, for C282Y and H63D, respectively) obtained from PBMCs.

RESULTS

The C282Y and H63D allele frequencies were 4.5 and 12.8 in patients with rheumatic diseases. Five patients were homozygote for H63D (2.4%), and one for C282Y (0.5%). Five patients were compound heterozygous (2.4%). The observed C282Y allele frequency in rheumatic patients with undifferentiated arthritis was 12.9 and exceeded that of healthy subjects (p = 0.01).

CONCLUSIONS

Determination of the HFE genotype is clinically useful in patients with arthritis of unknown origin, to allow early diagnosis of hemochromatosis.

Metabolic changes in the ageing man

The incidence of the metabolic syndrome, which is associated with visceral fat accumulation, hyperlipidaemia, hypertension, and type 2 diabetes mellitus, is raising with age. Insulin resistance and hyperinsulinaemia have been proposed as the causal link between the elements of the metabolic cluster mentioned above. The decrease in insulin action and insulin secretion can be explained by increased fat mass, decreased muscle mass, and by general endocrine changes related to ageing. Due to the increased incidence of cardiovascular diseases with the metabolic syndrome, lifestyle modifications including weight loss achieved by a low-calorie diet and physical activity should be promoted to increase insulin sensitivity and to prevent glucose intolerance and type 2 diabetes mellitus in ageing subjects.