Outcomes of MR-Guided Stereotactic Body Radiotherapy (MRgSBRT) for Adrenal Metastases: A Multi-Institutional Pooled Analysis

PURPOSE/OBJECTIVE(S)

Stereotactic body radiotherapy (SBRT) is an effective treatment for adrenal metastases, but it is technically challenging and there are concerns about toxicity due to the proximity of organs at risk. We hypothesized that MR-guided SBRT (MRgSBRT) using a 0.35 T MR-Linac for adrenal metastases can achieve durable local control (LC) with a low probability of toxicity.

MATERIALS/METHODS

In an ethics-approved study, we analyzed clinical and dosimetric data of patients treated with MRgSBRT at 10 institutions between 2016-2022. LC, local progression-free survival (LPFS), distant progression-free survival (DPFS) and overall survival (OS) were estimated using Kaplan-Meier method and log-rank test. Responses were evaluated using RECIST criteria. Toxicity was graded according to CTCAE (v4.0). OS and DPFS were calculated on a per-patient basis, while LC and LPFS were calculated on a per-lesion basis.

RESULTS

A total of 249 patients (260 adrenal lesions) were included; median age was 65 years (range 28-91), 65.5% were male, 83.9% had ECOG PS 0-1. The most common primary tumor was lung cancer (69.1%). Adrenal metastases were synchronous, metachronous, oligoprogressive or oligopersistent in 20%, 41.5%, 35.8% and 2.7% of patients, respectively. Metastatic pattern was solitary in 26.9%, oligometastatic in 57.3% and polymetastatic in 15.8% of patients. Right-sided metastases comprised 40%, left-sided 51.5% and lesions were bilateral in 8.5%. Chemotherapy and immunotherapy were administered in 67.1% and 60.6% of patients, respectively. Median gross tumor volume was 21.8 cc (range 1.1-383.2) and median planning target volume was 36.9 cc (range 3.6-516.9). Median total dose was 45 Gy (range 16-60), median fraction number was 5 (range 1-8) and median fraction dose used was 10 Gy (range 5-24). Median BED10 was 100 Gy (range 37.5-132); 87.8% of fractions used adapted plans. At a median follow-up was 17.7 months (IQR 5.5-21.7), local responses were scored as complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD) in 36.9%, 28.2%, 25.7%, and 9.1%, respectively. Median OS was 30.4 months, with 1- and 2- year OS rates of 75.3% and 57.1%, respectively. On multivariate analysis, significantly higher OS rates were seen in patients achieving a CR (p = 0.007, HR 0.50) and with ECOG scores of 0-1 (p = 0.001, HR 0.43). One- and 2- year LPFS rates were 94.5% and 88.8%, respectively. No local recurrences were observed after treatment to a BED10>100 or with single fraction (range 16-24 Gy). Only 2 patients (0.8%) had ≥grade 3 chronic toxicity.

CONCLUSION

This multi-institutional study of MRgSBRT outcomes for adrenal metastases revealed a 2-year LPFS of 89%, with a <1% risk of ≥grade 3 toxicity. Daily adaptation was performed in 90% of plans, indicating a beneficial role for MR guidance.

Common genetic variants do not predict recurrent events in coronary heart disease patients

Background

It is unclear whether genetic variants identified from single nucleotide polymorphisms (SNPs) strongly associated with coronary heart disease (CHD) in genome-wide association studies (GWAS), or a genetic risk score (GRS) derived from them, can help stratify risk of recurrent events in patients with CHD.

Methods

Study subjects were enrolled at the close-out of the LIPID randomised controlled trial of pravastatin vs placebo. Entry to the trial had required a history of acute coronary syndrome 3–36 months previously, and patients were in the trial for a mean of 36 months. Patients who consented to a blood sample were genotyped with a custom designed array chip with SNPs chosen from known CHD-associated loci identified in previous GWAS. We evaluated outcomes in these patients over the following 10 years.

Results

Over the 10-year follow-up of the cohort of 4932 patients, 1558 deaths, 898 cardiovascular deaths, 727 CHD deaths and 375 cancer deaths occurred. There were no significant associations between individual SNPs and outcomes before or after adjustment for confounding variables and for multiple testing. A previously validated 27 SNP GRS derived from SNPs with the strongest associations with CHD also did not show any independent association with recurrent major cardiovascular events.

Conclusions

Genetic variants based on individual single nucleotide polymorphisms strongly associated with coronary heart disease in genome wide association studies or an abbreviated genetic risk score derived from them did not help risk profiling in this well-characterised cohort with 10-year follow-up. Other approaches will be needed to incorporate genetic profiling into clinically relevant stratification of long-term risk of recurrent events in CHD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02520-0.

Recent advances of PET imaging in clinical radiation oncology

Radiotherapy and radiation oncology play a key role in the clinical management of patients suffering from oncological diseases. In clinical routine, anatomic imaging such as contrast-enhanced CT and MRI are widely available and are usually used to improve the target volume delineation for subsequent radiotherapy. Moreover, these modalities are also used for treatment monitoring after radiotherapy. However, some diagnostic questions cannot be sufficiently addressed by the mere use standard morphological imaging. Therefore, positron emission tomography (PET) imaging gains increasing clinical significance in the management of oncological patients undergoing radiotherapy, as PET allows the visualization and quantification of tumoral features on a molecular level beyond the mere morphological extent shown by conventional imaging, such as tumor metabolism or receptor expression. The tumor metabolism or receptor expression information derived from PET can be used as tool for visualization of tumor extent, for assessing response during and after therapy, for prediction of patterns of failure and for definition of the volume in need of dose-escalation. This review focuses on recent and current advances of PET imaging within the field of clinical radiotherapy / radiation oncology in several oncological entities (neuro-oncology, head & neck cancer, lung cancer, gastrointestinal tumors and prostate cancer) with particular emphasis on radiotherapy planning, response assessment after radiotherapy and prognostication.

Enlargement of the WHO international repository for platelet transfusion-relevant bacteria reference strains

BACKGROUND AND OBJECTIVES

Interventions to prevent and detect bacterial contamination of platelet concentrates (PCs) have reduced, but not eliminated the sepsis risk. Standardized bacterial strains are needed to validate detection and pathogen reduction technologies in PCs. Following the establishment of the First International Reference Repository of Platelet Transfusion-Relevant Bacterial Reference Strains (the 'repository'), the World Health Organization (WHO) Expert Committee on Biological Standardisation (ECBS) endorsed further repository expansion.

MATERIALS AND METHODS

Sixteen bacterial strains, including the four repository strains, were distributed from the Paul-Ehrlich-Institut (PEI) to 14 laboratories in 10 countries for enumeration, identification and growth measurement on days 2, 4 and 7 after low spiking levels [10-25 colony-forming units (CFU)/PC bag]. Spore-forming (Bacillus cereusPEI-B-P-07-S, Bacillus thuringiensisPEI-B-P-57-S), Gram-negative (Enterobacter cloacaePEI-B-P-43, Morganella morganiiPEI-B-P-74, PEI-B-P-91, Proteus mirabilisPEI-B-P-55, Pseudomonas fluorescensPEI-B-P-77, Salmonella choleraesuisPEI-B-P-78, Serratia marcescensPEI-B-P-56) and Gram-positive (Staphylococcus aureusPEI-B-P-63, Streptococcus dysgalactiaePEI-B-P-71, Streptococcus bovisPEI-B-P-61) strains were evaluated.

RESULTS

Bacterial viability was conserved after transport to the participating laboratories with one exception (M. morganiiPEI-B-P-74). All other strains showed moderate-to-excellent growth. Bacillus cereus, B. thuringiensis, E. coli, K. pneumoniae, P. fluorescens, S. marcescens, S. aureus and S. dysgalactiae grew to >10⁶ CFU/ml by day 2. Enterobacter cloacae, P. mirabilis, S. epidermidis, S. bovis and S. pyogenes achieved >10⁶ CFU/ml at day 4. Growth of S. choleraesuis was lower and highly variable.

CONCLUSION

The WHO ECBS approved all bacterial strains (except M. morganiiPEI-B-P-74 and S. choleraesuisPEI-B-P-78) for repository enlargement. The strains were stable, suitable for spiking with low CFU numbers, and proliferation was independent of the PC donor.

Development of a mitochondrial DNA real-time polymerase chain reaction assay for quality control of pathogen reduction with riboflavin and ultraviolet light

BACKGROUND AND OBJECTIVES

Transfusion is associated with a risk of infection and alloimmunization. Pathogen reduction using riboflavin and UV light (Mirasol treatment) inactivates pathogens and leucocytes. With increasing adoption of the technology in clinical use, regulatory agencies have recommended the introduction of quality control measures to monitor pathogen reduction efficacy. We sought to develop a real-time PCR-based assay to document the impact of pathogen reduction on the mitochondrial genome in blood components.

MATERIALS AND METHODS

DNA was extracted from platelet and plasma components before and after treatment with riboflavin and UV light. Inhibition of PCR amplification of mitochondrial DNA (mtDNA) in short- and long-amplicon target regions, ranging from under 200 base pairs (bp) to over 1800 bp, was measured in treated relative to untreated components.

RESULTS

Pathogen reduction of platelets using riboflavin and UV light resulted in inhibition of PCR amplification of long-amplicon mtDNA targets, demonstrating approximately 1 log reduction of amplification relative to untreated products. Amplification of short-amplicon mtDNA targets was not affected by treatment. Evaluation of 110 blinded platelet samples from the PREPAReS clinical trial resulted in prediction of treatment status with 100% accuracy. Pathogen reduction of plasma components resulted in similar levels of PCR inhibition, while testing of 30 blinded plasma samples resulted in prediction of treatment status with 93% accuracy.

CONCLUSION

A differential sized amplicon real-time PCR assay of mitochondrial DNA effectively documents nucleic acid damage induced by Mirasol treatment of platelets. The use of the assay for plasma product pathogen reduction requires further investigation.

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria

BACKGROUND

Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods.

MATERIAL AND METHODS

Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation.

RESULTS

Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19-1·32 × 10(7) CFU/ml, S. pyogenes: 0·58-0·69 × 10(7) CFU/ml, K. pneumoniae: 18·71-20·26 × 10(7) CFU/ml and E. coli: 1·78-2·10 × 10(7) CFU/ml.

CONCLUSION

The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low-titre spiking of blood components, (ii) the property of donor-independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion-Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository.

Mirasol Pathogen Reduction Technology treatment does not affect acute lung injury in a two-event in vivo model caused by stored blood components

INTRODUCTION

Mirasol Pathogen Reduction Technology (PRT) treatment uses riboflavin and UV light to inactivate pathogens in blood components. Neutrophil [polymorphonuclear cells (PMN)] priming activity accumulates during routine storage of cellular blood components, and this activity has been implicated in transfusion-related acute lung injury (TRALI). We hypothesize that PRT-treatment of blood components affects the priming activity generated during storage of packed RBCs (PRBCs) or platelet concentrates (PCs), which can elicit ALI in vivo.

METHODS

Plasma, PRBCs and PCs were isolated from healthy donor's whole blood or by apheresis. Half of a collected unit was treated with PRT treatment and the remainder was left as an unmodified control. Supernatant was collected during storage of PCs and PRBCs and assayed for PMN priming activity and used as the second event in a two-event in vivo model of TRALI.

RESULTS

PRT treatment did not induce priming activity in plasma or affect the priming activity generated during storage of PCs or PRBCs as compared with the unmodified controls. The supernatants from stored, but not fresh, PCs and PRBCs did cause ALI as the second event in a two-event animal model of TRALI, which was unaffected by PRT treatment. We conclude that the PRT treatment does not induce priming activity in plasma nor does it affect the priming activity generated during storage of PCs or PRBCs or their ability to cause ALI as the second event in a two-event in vivo model of TRALI. Moreover, the amount of priming activity in TRIMA-isolated PCs was significantly less than SPECTRA-isolated PCs.

FcgammaRIIB-mediated inhibition of T-cell receptor signal transduction involves the phosphorylation of SH2-containing inositol 5-phosphatase (SHIP), dephosphorylation of the linker of activated T-cells (LAT) and inhibition of calcium mobilization

The low-affinity receptor for immunoglobulin G, FcgammaRIIB, is expressed on most B-cells and on immature and activated mature T-cells. Co-aggregation of FcgammaRIIB with the B-cell antigen receptor (BCR) leads to attenuation of BCR-induced blastogenesis and cell proliferation via inhibition of p21(ras), phosphatidylinositol 3-kinase (PI3-K) and phospholipase Cgamma (PLCgamma) activation. These effects are mediated, at least in part, by the recruitment of SH2-containing protein tyrosine phosphatase-1 (SHP-1) and -2 (SHP-2) and SH2-containing inositol 5-phosphatase (SHIP). In this report, we demonstrate that FcgammaRIIB co-aggregation with the T-cell antigen receptor (TCR), which may occur when T-cells recognize antibody-coated target cells, leads to inhibition of TCR-induced phosphorylation of the linker of activated T-cells (LAT). When phosphorylated, LAT functions as an adapter molecule and recruits PI3-K. Additionally, we demonstrate that PI3-K is required for TCR-induced Ca(2+) mobilization. Together, these data suggest that FcgammaRIIB may inhibit TCR-mediated Ca(2+) mobilization, in part via inhibition of LAT phosphorylation and subsequent inhibition of PI3-K activation. A similar mechanism has been described in B-cells, where FcgammaRIIB co-aggregation with the BCR leads to inhibition of PI3-K activity via dephosphorylation of CD19. It is likely that, in both cell types, levels of PtdIns(3,4,5)P(3) are additionally modulated via the enzymic activity of SHIP.

Partially distinct molecular mechanisms mediate inhibitory FcgammaRIIB signaling in resting and activated B cells

FcgammaRIIB functions as an inhibitory receptor to dampen B cell Ag receptor signals and immune responses. Accumulating evidence indicates that ex vivo B cells require the inositol 5-phosphatase, Src homology domain 2-containing inositol 5-phosphatase (SHIP), for FcgammaRIIB-mediated inhibitory signaling. However, we report here that LPS-activated primary B cells do not require SHIP and thus differ from resting B cells. SHIP-deficient B cell blasts display efficient FcgammaRIIB-dependent inhibition of calcium mobilization as well as Akt and extracellular signal-related protein kinase phosphorylation. Surprisingly, FcgammaRIIB-dependent degradation of phosphatidylinositol 3,4,5-trisphosphate and conversion into phosphatidylinositol 3,4-bisphosphate occur in SHIP-deficient B cell blasts, demonstrating the function of an additional inositol 5-phosphatase. Further analysis reveals that while resting cells express only SHIP, B cell blasts also express the recently described inositol 5-phosphatase, SHIP-2. Finally, data suggest that both SHIP-2 and SHIP can mediate downstream biologic consequences of FcgammaRIIB signaling, including inhibition of the proliferative response.

Ligation of the CD4 receptor induces activation-independent down-regulation of L-selectin

Lymphocyte circulation plays an important role in the generation of a specific immune response. Mature lymphocytes continuously circulate between blood and lymph, entering the lymphoid tissue via high endothelial venules. Trafficking across high endothelial venules of peripheral lymph nodes (PLN) depends on the expression of L-selectin. It has been shown that L-selectin is rapidly cleaved from the surface by a metalloproteinase after in vitro activation. Here, we show that ligation of CD4, without ligation of the T cell receptor for antigen, causes down-regulation of L-selectin on T helper cells. This down-regulation is caused by proteolytic cleavage by a metalloproteinase and is reversible by the addition of hydroxamic acid-based metalloproteinase inhibitors. We show that in vivo down-regulation of L-selectin in huCD4tg mice by mAb reduces the homing of lymphocytes to PLN in adoptive transfer experiments. Because CD4 is a coreceptor for HIV-1, the down-regulation of L-selectin induced by CD4 ligation could play a role in the pathogenesis of AIDS. We provide evidence that CD4 ligation by HIV-1 induces metalloproteinase-dependent L-selectin down-regulation. Reduced levels of L-selectin expression might contribute to immune deficiency in individuals infected with HIV by inhibiting T cell redistribution and decreasing the probability of an encounter between specific lymphocytes and viral antigens in PLN.

Apoptosis of CD4+ and CD8+ T cells isolated immediately ex vivo correlates with disease severity in human immunodeficiency virus type 1 infection

Apoptosis of CD4+ and CD8+ T cells has been shown in peripheral blood mononuclear cells (PBMCs) from HIV-infected adults analyzed after overnight culture. Because cell death may be an artifact of in vitro culture, and because there is little information on apoptosis in pediatric HIV disease, we undertook a cross-sectional analysis of apoptosis in PBMCs analyzed immediately ex vivo in HIV-infected children and adults. PBMCs from 22 children, four adolescents, and nine adults and seronegative age-matched control subjects were stained for CD4 and CD8 surface markers. Apoptotic cells were detected in a newly characterized flow cytometric assay by diminished forward and increased side scatter. Children with the most advanced disease had 9.9% (SEM 1.8) apoptotic CD4+ T cells above control, significantly higher than in asymptomatic patients [0.4% (SEM 2.3)], those with mild disease [2.2% (SEM 1.83)], and those with moderate disease [2.5 (SEM 3.6)] (p = 0.015). The percentages of both CD4+ and CD8+ T cell apoptosis were directly related to CD4+ T cell depletion (R2 = 0.23; p = 0.006; n = 32 and R2 = 0.2; p = 0.012; n = 30, respectively). Patients who responded to antiretroviral therapy with the greatest increase in CD4+ T cell percentage had the least CD4+ T cell apoptosis (R2 = 0.15; p = 0.1; n = 19). These findings show that the rate or extent of T cell death by apoptosis percentage of T cell apoptosis is significantly increased in HIV-infected children. The observed correlation of both CD4+ and CD8+ T cell apoptosis with CD4+ T cell depletion suggests that apoptosis plays a role in HIV pathogenesis and may be a useful marker of disease activity.

Apoptosis in HIV-1 Infection

We have studied apoptosis in lymph node and peripheral blood mononuclear cells (PBMCs) from HIV-infected children and adults and SIV-infected rhesus macaques. In lymph nodes, we found that apoptosis and productive infection occurred only rarely in the same cell. There was, however, a direct correlation between the numbers of apoptotic and productively-infected cells. In HIV-infected children, we found a direct correlation between disease severity and percentage CD4+ T cell apoptosis (p = 0.001). Both CD4+ and CD8+ T cell apoptosis were directly related to CD4+ T cell depletion (p = 0.006 and p = 0.01, respectively). In addition, we found a trend towards diminished CD4+ T cell apoptosis on anti-retroviral agents. These findings suggest that apoptosis of uninfected cells may be important in HIV pathogenesis and that measurement of apoptosis may be a useful marker of disease activity.