Effects of a novel peptide Ac-SDKP in radiation-induced coronary endothelial damage and resting myocardial blood flow

BACKGROUND

Cancer survivors treated with thoracic ionizing radiation are at higher risk of premature death due to myocardial ischemia. No therapy is currently available to prevent or mitigate these effects. We tested the hypothesis that an endogenous tetrapeptide N-acetyl-Ser-Asp-Lys-Pro (Ac-SDKP) counteracts radiation-induced coronary vascular fibrosis and endothelial cell loss and preserves myocardial blood flow.

METHODS

We examined a rat model with external-beam-radiation exposure to the cardiac silhouette. We treated a subgroup of irradiated rats with subcutaneous Ac-SDKP for 18-weeks. We performed cardiac MRI with Gadolinium contrast to examine resting myocardial blood flow content. Upon sacrifice, we examined coronary endothelial-cell-density, fibrosis, apoptosis and endothelial tight-junction proteins (TJP). In vitro, we examined Ac-SDKP uptake by the endothelial cells and tested its effects on radiation-induced reactive oxygen species (ROS) generation. In vivo, we injected labeled Ac-SDKP intravenously and examined its endothelial localization after 4-h.

RESULTS

We found that radiation exposure led to reduced resting myocardial blood flow content. There was concomitant endothelial cell loss and coronary fibrosis. Smaller vessels and capillaries showed more severe changes than larger vessels. Real-time PCR and confocal microscopy showed radiation-induced loss of TJ proteins including-claudin-1 and junctional adhesion molecule-2 (JAM-2). Ac-SDKP normalized myocardial blood flow content, inhibited endothelial cell loss, reduced coronary fibrosis and restored TJ-assembly. In vitro, Ac-SDKP localized to endothelial cells and inhibited radiation-induced endothelial ROS generation. In vivo, labeled Ac-SDKP was visualized into the endothelium 4-h after the intravenous injection.

CONCLUSIONS

We concluded that Ac-SDKP has protective effects against radiation-induced reduction of myocardial blood flow. Such protective effects are likely mediated by neutralization of ROS-mediated injury, preservation of endothelial integrity and inhibition of fibrosis. This demonstrates a strong therapeutic potential of Ac-SDKP to counteract radiotherapy-induced coronary disease.

Preclinical Evaluation of Gilteritinib on NPM1-ALK-Driven Anaplastic Large Cell Lymphoma Cells

Anaplastic large cell lymphoma (ALCL) is an aggressive type of non-Hodgkin lymphoma. More than three-fourths of anaplastic lymphoma kinase (ALK)-positive ALCL cases express the nucleophosmin 1 (NPM1)-ALK fusion gene as a result of t(2;5) chromosomal translocation. The homodimerization of NPM1-ALK fusion protein mediates constitutive activation of the chimeric tyrosine kinase activity and downstream signaling pathways responsible for lymphoma cell proliferation and survival. Gilteritinib is a tyrosine kinase inhibitor recently approved by the FDA for the treatment of FMS-like tyrosine kinase mutation-positive acute myeloid leukemia. In this study, we demonstrate for the first time gilteritinib-mediated growth inhibitory effects on NPM1-ALK-driven ALCL cells. We utilized a total of five ALCL model cell lines, including both human and murine. Gilteritinib treatment inhibits NPM1-ALK fusion kinase phosphorylation and downstream signaling, resulting in induced apoptosis. Gilteritinib-mediated apoptosis was associated with caspase 3/9, PARP cleavage, the increased expression of proapoptotic protein BAD, and decreased expression of antiapoptotic proteins, survivin and MCL-1. We also found downregulation of fusion kinase activity resulted in decreased c-Myc protein levels. Furthermore, cell-cycle analysis indicated gilteritinib induced G0-G1-phase cell-cycle arrest and reduced CD30 expression. In summary, our preclinical studies explored the novel therapeutic potential of gilteritinib in the treatment of ALCL cells expressing NPM1-ALK and potentially in other ALK or ALK fusion-driven hematologic or solid malignancies. IMPLICATIONS: Our preclinical results explore the use of gilteritinib for the treatment of NPM1-ALK-driven ALCL cells and pave a path for developing future clinical trials. VISUAL OVERVIEW: http://mcr.aacrjournals.org/content/molcanres/19/5/913/F1.large.jpg.

Association of Adjuvant Chemotherapy With Overall Survival in Patients With Early-Stage Breast Cancer and 21-Gene Recurrence Scores of 26 or Higher

This cohort study investigates the association of overall survival with receiving chemotherapy among patients with early-stage breast cancer and recurrence scores of 26 to 30 vs those with recurrence scores of 31 or greater.

Routine surveillance scanning in HNSCC: Lung screening CT scans have value but head and neck scans do not

OBJECTIVES

To examine the utility of computed tomography (CT) imaging during routine surveillance for the detection of recurrent head and neck squamous cell carcinoma (HNSCC).

MATERIALS/METHODS

Clinical characteristics of HNSCC patients treated between 2008 and 2017 with radiation therapy or concurrent chemoradiation were abstracted from medical records. In patients who achieved a complete response to treatment by positron emission tomography scan, surveillance CT scans were conducted to the maxillofacial area, neck, and chest every 3 months in year 1, every 6 months in year 2, and every 12 months in years 3 and beyond.

RESULTS

Within the entire cohort (n = 534), complete response was achieved in 446 patients (83.5%); of these, 84 (15.7%) patients had a recurrence. Among the 84 patients with disease recurrence, 25 (30%) patients remained alive, of which 15 (18%) underwent successful salvage treatment and became free of disease. Lung screening CT scans detected failure in 8 of these successfully salvaged patients. Among the 8 patients successfully salvaged for locoregional recurrence, 3 failures were asymptomatic at onset and detected by laryngoscope or dental exam. The remaining 5 failures were symptomatic and detected upon work up prompted by symptoms. Maxillofacial and neck surveillance CT imaging failed to detect any successfully salvaged patients.

CONCLUSIONS

Routine surveillance for HNSCC patients with lung CT imaging had value but routine head and neck CT scans failed to identify any successfully salvaged patients. Given this finding, routine CT imaging surveillance in HNSCC patients should be restricted to annual lung screening with low-dose chest CT.

A Retrospective Cohort Study of Myosteatosis and Quality of Life in Head and Neck Cancer Patients

Head and neck cancer (HNC) treatment-related morbidity can be detrimental to quality of life (QOL). Myosteatosis is associated with poor QOL in multiple cancers. If predictive of poor QOL trajectories, myosteatosis would be a tool for clinicians to determine which patients may require additional support during treatment. The purpose of this study was to determine if pretreatment myosteatosis is associated with a poor QOL trajectory following treatment completion.

METHODS

In a retrospective cohort design, myosteatosis was determined from pretreatment CT scans. Both physical and global QOL score was assessed through patient interview on follow-up appointment. Demographic, cancer-specific, and social covariates were collected, reported, and considered as potential confounders.

RESULTS

The population of 163 patients was mostly male (82.2%) and white (91.4%) with oropharyngeal cancer (55.8%). Males with myosteatosis had a physical QOL score 46.84 points lower at one-year following treatment completion (p = 0.01) than those with normal muscle density (p = 0.01). Males with myosteatosis averaged 57.57 points lower at one-year post-treatment (p = 0.01) in global QOL scores.

CONCLUSIONS

Over one year following completion of treatment, patients with myosteatosis reported worse physical and global QOL scores than patients with normal muscle density.

Excretable, ultrasmall hexagonal NaGdF4:Yb50% nanoparticles for bimodal imaging and radiosensitization

BACKGROUND

In this study, we report on the synthesis, imaging, and radiosensitizing properties of ultrasmall β-NaGdF4:Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided that the nanoparticles are taken up intracellularly.

RESULTS

Our ultrasmall β-NaGdF4:Yb50% nanoparticles demonstrate improvement in T1-weighted contrast over the standard clinical MR imaging agent Gd-DTPA and similar CT signal enhancement capabilities as commercial agent iohexol. A 2 Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF4:Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF4:Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd3+ ions via ICP-MS.

CONCLUSION

These biocompatible and in vivo clearable ultrasmall NaGdF4:Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.

Hope for progress after 40 years of futility? Novel approaches in the treatment of advanced stage III and IV non-small-cell-lung cancer: Stereotactic body radiation therapy, mediastinal lymphadenectomy, and novel systemic therapy

Non-small-cell lung cancer (NSCLC) remains a leading cause of cancer mortality. The majority of patients present with advanced (stage III-IV) disease. Such patients are treated with a variety of therapies including surgery, radiation, and chemotherapy. Despite decades of work, however, overall survival in this group has been resistant to any substantial improvement. This review briefly details the evolution to the current standard of care for advanced NSCLC, advances in systemic therapy, and novel techniques (stereotactic body radiation therapy [SBRT], and transcervical extended mediastinal lymphadenectomy [TEMLA] or video-assisted mediastinal lymphadenectomy [VAMLA]) that have been used in localized NSCLC. The utility of these techniques in advanced stage therapy and potential methods of combining these novel techniques with systemic therapy to improve survival are discussed.

Brachial Plexopathy After Single-Fraction Stereotactic Body Radiation Therapy in Apical Lung Tumors

PURPOSE

The objective of this study was to evaluate the incidence of brachial plexus injury (BPI) after single-fraction stereotactic body radiation therapy (SBRT) to apical lung tumors.

METHODS AND MATERIALS

A retrospective cohort analysis was performed of all patients treated with single-fraction lung SBRT at our institution from 2007 to 2022. Apical tumors were identified as those with an epicenter located above the arch of the aorta. Dosimetric analysis of dose to the brachial plexus (BP) was done using both the subclavian vessel (SCV) surrogate structure and anatomic BP. BPI was assessed per Common Terminology Criteria for Adverse Events, version 4.0, as regional paresthesia, marked discomfort and muscle weakness, and limited movement of the arm or hand.

RESULTS

A total of 45 patients met inclusion criteria with median follow-up of 21 months. There were 9 patients who exceeded the BP dose constraint using the SCV or anatomic BP volume. Only 1 patient (2.2%) developed grade 2 BPI, occurring 7 months after SBRT. Dose to the anatomic BP for the affected patient was 26.39 Gy. For the entire cohort, the median SCV and anatomic maximum BP doses were 8.44 and 7.14 Gy, respectively.

CONCLUSIONS

There is considerable variability in dose delivered to the BP after SBRT to apical lung tumors. BPI after single-fraction SBRT to apical tumors is rare and rates are comparable with those reported with multifraction regimens.

Right Atrial Dose Is Associated with Worse Outcome in Patients Undergoing Definitive Stereotactic Body Radiation Therapy for Central Lung Tumors

The consequence of cardiac substructure irradiation in patients receiving stereotactic body radiation therapy (SBRT) is not well characterized. We reviewed the charts of patients with central lung tumors managed by definitive SBRT from June 2010-April 2019. All patients were treated with five fractions, typically either 5000 cGy (44.6%) or 5500 cGy (42.2%). Via a multi-patient atlas, fourteen cardiac substructures were autosegmented, manually reviewed and analyzed using dosimetric parameters. A total of 83 patients were included with a median follow up of 33.4 months. Univariate Cox regression analysis identified a D45% dose to the right atria and ventricle for further study. Sequential log-rank testing evaluating an association between non-cancer associated survival and D45% dose to the right atria or ventricle and association was employed, identifying candidate cutoff values of 890.3 cGy and 564.4 cGy, respectively. Kaplan-Meier analysis using the reported cutoff values found the D45% right atria constraint to be significantly associated with non-cancer associated (p ≤ 0.001) and overall survival (p ≤ 0.001) but not the right ventricle constraint. Within a multivariate model, the proposed right atria D45% cutoff remained significantly correlated with non-cancer associated survival (Hazard's Ratio (HR) ≤ 8.5, 95% confidence interval (CI) 1.1-64.5, p ≤ 0.04) and OS (HR ≤ 6.1, 95% CI 1.0-36.8, p ≤ 0.04). In conclusion, a dose to D45% of the right atria significantly correlated with outcome and the candidate constraint of 890 cGy stratified non-cancer associated and OS. The inclusion of these findings with previously characterized relationships between proximal airway constraints and survival enhances our understanding of why centrally located tumors are high risk and potentially identifies key constraints in organ at risk prioritization.

Outcomes with HLA-matched unrelated donor versus haploidentical hematopoietic cell transplantation

We investigated the outcomes after adult haploidentical (haplo) and matched unrelated donor (MUD) hematopoietic cell transplantation (HCT) in a single-center study (n = 452) including 276 MUD and 176 haplo transplants. Myeloablative (37%) and reduced-intensity conditioning (63%) were performed. Graft sources included peripheral blood (50%) and bone marrow (50%). GVHD prophylaxis included tacrolimus/methotrexate (53%) and post-transplant cyclophosphamide-based (47%). In MUD versus haplo HCT recipients, a similar incidence of neutrophil engraftment (18 vs 17 days, p = 0.895), grade II-IV acute GVHD (51% vs 50%, p = 0.773), relapse (26% vs 23%, p = 0.578), non-relapse mortality (22% vs 23%, p = 0.817), 1-year disease-free survival (62% vs 63%. p = 0.921), and 1-year overall survival (73% vs 74%, p = 0.744) were observed. Earlier platelet engraftment (22 vs 27 days, p < 0.001) and higher chronic GVHD (45% vs 35%, p = 0.040) were noted in MUD as compared to haplo HCT. Allogeneic transplantation should be done promptly whenever indicated, utilizing either matched unrelated or haploidentical donors.

Evaluation of risk stratification using gene expression assays in patients with breast cancer receiving neoadjuvant chemotherapy

PURPOSE

To evaluate the association of various gene expression assays with pathologic complete response (pCR) in the setting of neoadjuvant chemotherapy among patients with breast cancer METHODS: The National Cancer Database (NCDB) was queried for women diagnosed between 2010 and 2017 with stage I-III breast cancer who underwent neoadjuvant chemotherapy and either 21-gene recurrence score (RS) or 70-gene signature (GS). Logistic multivariable analysis (MVA) was performed to identify variables associated with pCR.

RESULTS

A total of 3009 patients met our inclusion criteria. The median follow up was 48.0 months (interquartile range 32.2-66.7 months). On logistic MVA for all patients, those with a high risk from GS (adjusted odds ratio [aOR] 3.23, 95% confidence interval [CI] 1.49-8.13, p = 0.006) or with RS ≥ 31 (aOR 1.99, 95% CI 1.41-2.82, p < 0.001) were more likely to have pCR. When compared to RS ≥ 31, a high risk from GS was not associated with pCR (aOR 1.01, 95% CI 0.75-1.37, p = 0.94). However, among those with favorable hormone receptor status, similar findings were noted, except that those with a high risk group from GS were less likely to have pCR compared to those with RS ≥ 31 (aOR 0.65, 95% CI 0.43-0.96, p = 0.03). When analyses were repeated using a high risk group from RS defined as RS ≥ 26 among those with favorable hormone receptor status, RS ≥ 26 was not associated with pCR when compared to the high risk from GS (aOR 0.74, 0.50-1.07, p = 0.12).

CONCLUSIONS

To our knowledge, this is the largest study using a nationwide oncology database suggesting that high recurrence risk groups in both assays were associated with pCR. Among those with favorable hormone receptor status, RS ≥ 31 may be a more selective prognostic marker for pCR.

Improved dose homogeneity using electronic compensation technique for total body irradiation

In total body irradiation (TBI) utilizing large parallel-opposed fields, the manual placement of lead compensators has conventionally been used to compensate for the varying thickness throughout the body. The goal of this study is to pursue utilizing the modern electronic compensation (E-comp) technique to more accurately deliver dose to TBI patients. Bilateral parallel-opposed TBI treatment plans were created using E-comp for 15 patients for whom CT data had been previously acquired. A desirable fluence pattern was manually painted within each field to yield a uniform dose distribution. The conventional compensation technique was simulated within the treatment planning system (TPS) using a field-in-field (FIF) method. This allows for a meaningful evaluation of the E-comp technique in comparison to the conventional method. Dose-volume histograms (DVH) were computed for all treatment plans. The mean total body dose using E-comp deviates from the prescribed dose (4 Gy) by an average of 2.4%. The mean total body dose using the conventional compensation deviates from the prescribed dose by an average of 4.5%. In all cases, the mean body dose calculated using E-comp technique deviates less than 10% from that of conventional compensation. The average reduction in maximum dose using E-comp compared to that of the conventional method was 30.3% ± 6.6% (standard deviation). In all cases, the s-index for the E-comp technique was lower (10.5% ± 0.7%) than that of the conventional method (15.8% ± 4.4%), indicating a more homogenous dose distribution. In conclusion, a large reduction in maximum body dose can be seen using the proposed E-comp technique while still producing a mean body dose that accurately complies with the prescription dose. Dose homogeneity was quantified using s-index which demonstrated a reduction in hotspots with E-comp technique. Electronic compensation technique is capable of more accurately delivering a total body dose compared to conventional methods.

The dose penumbra of a custom-made shield used in hemibody skin electron irradiation

We report our technique for hemibody skin electron irradiation with a custom-made plywood shield. The technique is similar to our clinical total skin electron irradiation (TSEI), performed with a six-pair dual field (Stanford technique) at an extended source-to-skin distance (SSD) of 377 cm, with the addition of a plywood shield placed at 50 cm from the patient. The shield is made of three layers of stan-dard 5/8'' thick plywood (total thickness of 4.75 cm) that are clamped securely on an adjustable-height stand. Gafchromic EBT3 films were used in assessing the shield's transmission factor and the extent of the dose penumbra region for two different shield-phantom gaps. The shield transmission factor was found to be about 10%. The width of the penumbra (80%-to-20% dose falloff) was measured to be 12 cm for a 50 cm shield-phantom gap, and reduced slightly to 10 cm for a 35 cm shield-phantom gap. In vivo dosimetry of a real case confirmed the expected shielded area dose.

Deep learning tools for the cancer clinic: an open-source framework with head and neck contour validation

BACKGROUND

With the rapid growth of deep learning research for medical applications comes the need for clinical personnel to be comfortable and familiar with these techniques. Taking a proven approach, we developed a straightforward open-source framework for producing automatic contours for head and neck planning computed tomography studies using a convolutional neural network (CNN).

METHODS

Anonymized studies of 229 patients treated at our clinic for head and neck cancer from 2014 to 2018 were used to train and validate the network. We trained a separate CNN iteration for each of 11 common organs at risk, and then used data from 19 patients previously set aside as test cases for evaluation. We used a commercial atlas-based automatic contouring tool as a comparative benchmark on these test cases to ensure acceptable CNN performance. For the CNN contours and the atlas-based contours, performance was measured using three quantitative metrics and physician reviews using survey and quantifiable correction time for each contour.

RESULTS

The CNN achieved statistically better scores than the atlas-based workflow on the quantitative metrics for 7 of the 11 organs at risk. In the physician review, the CNN contours were more likely to need minor corrections but less likely to need substantial corrections, and the cumulative correction time required was less than for the atlas-based contours for all but two test cases.

CONCLUSIONS

With this validation, we packaged the code framework and trained CNN parameters and a no-code, browser-based interface to facilitate reproducibility and expansion of the work. All scripts and files are available in a public GitHub repository and are ready for immediate use under the MIT license. Our work introduces a deep learning tool for automatic contouring that is easy for novice personnel to use.

Evaluation of cytomegalovirus reactivation and tolerability in seropositive umbilical cord transplant patients after implementation of an intensive prevention strategy

OBJECTIVE/BACKGROUND

Cytomegalovirus (CMV) causes significant morbidity and mortality in CMV seropositive patients undergoing umbilical cord blood transplants (UCBT). Our study aimed to describe the incidence of CMV reactivation and burden of disease, as well as the tolerability of an intensive prevention strategy as compared to historical prevention.

METHODS

This was a retrospective chart review of 33 CMV seropositive patients that underwent UCBT. The intensive prevention strategy in UCBT consisted of ganciclovir 5mg/kg/d intravenously or valganciclovir 900mg by mouth daily initiated at the beginning of the conditioning regimen until Day -2. Then from Day -1 to Day +100, patients received valacyclovir 2g by mouth three times daily, and from Day +101 to Day +365, acyclovir 800mg by mouth twice daily. Historical standard prevention was acyclovir 800mg by mouth twice daily initiated at the beginning of the conditioning regimen until Day +365.

RESULTS

Thirty-three patients were included from 2008 to 2014. There were no differences in the adverse effects experienced between the two regimens (p=.4). CMV reactivation occurred significantly later with intensive prevention (p=.003). The median CMV viral titer at reactivation was lower in the intensive versus the historic prevention (1,800copies/mL and 2,700copies/mL, respectively), but was not significantly different. CMV disease occurred significantly less often in the intensive group (p=.039).

CONCLUSION

The results from this study indicate that the intensive prevention strategy was well tolerated, significantly delayed CMV reactivation, and patients had less CMV disease.

Survival outcome of adjuvant chemotherapy and high 21-gene recurrence score in early-stage breast cancer

Among patients with early-stage breast cancer and a high 21-gene recurrence score (RS) ≥ 26, it remains unclear on whether those with RS 26-30 would benefit from chemotherapy with a comparable magnitude as those with RS > 30. In addition, RS > 30 as an independent prognostic factor for breast cancer-specific survival (BCSS) and overall survival (OS) compared to RS 26-30 also remains unclear. The Surveillance, Epidemiology, and End Results (SEER) database was queried for patients diagnosed between 2010 and 2013 with hormone receptor-positive, HER2-negative, and T1-2N0 breast cancer with a RS ≥ 26. Primary end points were OS and BCSS, evaluated by using Kaplan-Meier method, log-rank test, and Cox multivariable analysis. Subgroups of RS 26-30 and RS > 30 were examined using propensity score matching to address selection bias. Among 5054 patients who met the inclusion criteria, adjuvant chemotherapy was associated with improved OS (HR 0.66, 95% CI 0.53-0.83, P < .001) and BCSS (HR 0.61, 95% CI 0.45-0.83, P = .001). In the subgroup of 943 matched pairs of patients with RS 26-30, the addition of chemotherapy remained statistically significant (OS: HR 0.52, 95% CI 0.34-0.79, P = .003; BCSS: HR 0.42, 95% CI 0.22-0.81, P = .009). Among 1194 matched pairs who underwent adjuvant chemotherapy, those with RS > 30 had worse outcomes than others with RS 26-30 (OS: HR 1.68, 95% CI 1.17-2.42, P = .005; BCSS: HR 1.92, 95% CI 1.17-3.15, P = .01). Our study builds on prior literature using a population-based database to suggest the association of adjuvant chemotherapy with improved survival among those with RS 26-30 and worse mortality associated with RS > 30 compared to RS 26-30.