Tests of Light-Lepton Universality in Angular Asymmetries of B^{0}→D^{*-}ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189  fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

Precise Measurement of the D_{s}^{+} Lifetime at Belle II

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207  fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9)  fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189  fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3  GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

Circulating cell-free methylated DNA reveals tissue-specific, cellular damage from radiation treatment

Radiation therapy is an effective cancer treatment, although damage to healthy tissues is common. Here we analyzed cell-free, methylated DNA released from dying cells into the circulation to evaluate radiation-induced cellular damage in different tissues. To map the circulating DNA fragments to human and mouse tissues, we established sequencing-based, cell-type-specific reference DNA methylation atlases. We found that cell-type-specific DNA blocks were mostly hypomethylated and located within signature genes of cellular identity. Cell-free DNA fragments were captured from serum samples by hybridization to CpG-rich DNA panels and mapped to the DNA methylation atlases. In a mouse model, thoracic radiation-induced tissue damage was reflected by dose-dependent increases in lung endothelial and cardiomyocyte methylated DNA in serum. The analysis of serum samples from patients with breast cancer undergoing radiation treatment revealed distinct dose-dependent and tissue-specific epithelial and endothelial responses to radiation across multiple organs. Strikingly, patients treated for right-sided breast cancers also showed increased hepatocyte and liver endothelial DNA in the circulation, indicating the impact on liver tissues. Thus, changes in cell-free methylated DNA can uncover cell-type-specific effects of radiation and provide a readout of the biologically effective radiation dose received by healthy tissues.

Search for an Invisible Z^{'} in a Final State with Two Muons and Missing Energy at Belle II

The L_{μ}-L_{τ} extension of the standard model predicts the existence of a lepton-flavor-universality-violating Z^{'} boson that couples only to the heavier lepton families. We search for such a Z^{'} through its invisible decay in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7  fb^{-1}. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×10^{-3} at low Z^{'} masses to 1 at Z^{'} masses of 8  GeV/c^{2}.

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II

We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8  fb^{-1}, produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} and τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. We report 95% confidence-level upper limits on the branching-fraction ratio B(τ^{-}→e^{-}α)/B(τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ}) in the range (1.1-9.7)×10^{-3} and on B(τ^{-}→μ^{-}α)/B(τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}) in the range (0.7-12.2)×10^{-3} for α masses between 0 and 1.6  GeV/c^{2}. These results provide the most stringent bounds on invisible boson production from τ decays.

Observation of e^{+}e^{-}→ωχ_{bJ}(1P) and Search for X_{b}→ωϒ(1S) at sqrt[s] near 10.75 GeV

We study the processes e^{+}e^{-}→ωχ_{bJ}(1P) (J=0, 1, or 2) using samples at center-of-mass energies sqrt[s]=10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7  fb^{-1} of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the ϒ(4S) resonance. We report the first observation of ωχ_{bJ}(1P) signals at sqrt[s]=10.745  GeV. By combining Belle II data with Belle results at sqrt[s]=10.867  GeV, we find energy dependencies of the Born cross sections for e^{+}e^{-}→ωχ_{b1,b2}(1P) to be consistent with the shape of the ϒ(10753) state. These data indicate that the internal structures of the ϒ(10753) and ϒ(10860) states may differ. Including data at sqrt[s]=10.653  GeV, we also search for the bottomonium equivalent of the X(3872) state decaying into ωϒ(1S). No significant signal is observed for masses between 10.45 and 10.65  GeV/c^{2}.

Measurement of the Λ_{c}^{+} Lifetime

An absolute measurement of the Λ_{c}^{+} lifetime is reported using Λ_{c}^{+}→pK^{-}π^{+} decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2  fb^{-1}. The result, τ(Λ_{c}^{+})=203.20±0.89±0.77  fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.

Search for a Dark Photon and an Invisible Dark Higgs Boson in μ^{+}μ^{-} and Missing Energy Final States with the Belle II Experiment

The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A^{'} and h^{'} in the dark Higgsstrahlung process e^{+}e^{-}→A^{'}h^{'} with A^{'}→μ^{+}μ^{-} and h^{'} invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34  fb^{-1}, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7-5.0 fb on the cross section and in the range of 1.7×10^{-8}-200×10^{-8} on the effective coupling ϵ^{2}×α_{D} for the A^{'} mass in the range of 4.0  GeV/c^{2}<M_{A^{'}}<9.7  GeV/c^{2} and for the h^{'} mass M_{h^{'}}<M_{A^{'}}, where ϵ is the mixing strength between the standard model and the dark photon and α_{D} is the coupling of the dark photon to the dark Higgs boson. Our limits are the first in this mass range.

Impact of Clinician Linkage on Unequal Access to High-Volume Hospitals for Colorectal Cancer Surgery

BACKGROUND

Understanding drivers of persistent surgical disparities remains an important area of cancer care delivery and policy. The degree to which clinician linkages contribute to disparities in access to quality colorectal cancer surgery is unknown. Using hospital surgical volume as a proxy for quality, the study team evaluated how clinician linkages impact access to colorectal cancer surgery at high-volume hospitals (HVHs).

STUDY DESIGN

Maryland's Health Services Cost Review Commission was used to evaluate 6,909 patients who underwent colon or rectal cancer operations from 2013 to 2018. Two linkages based on patient sharing were examined separately for colon and rectal cancer surgery: (1) from primary care clinicians to specialists (gastroenterologist or medical oncologist) and (2) from specialists to surgeons (general or colorectal). A referral link was defined as 9 or more shared patients between 2 clinicians. Adjusted regression models examined associations between referral links and odds of receiving colon or rectal cancer operations at HVHs.

RESULTS

The cohort included 5,645 colon and 1,264 rectal cancer patients across 52 hospitals. Every additional referral link between a primary care clinician and a specialist connected to a HVH was associated with a 12% and 14% increased likelihood of receiving colon (odds ratio [OR] 1.12, CI 1.07 to 1.17) and rectal (OR 1.14, CI 1.08 to 1.20]) cancer operations at a HVH, respectively. Every additional referral link between a specialist and a surgeon at a HVH was associated with at least a 25% increased likelihood of receiving colon (OR 1.28, CI 1.20 to 1.36) and rectal (OR 1.25, CI 1.15 to 1.36) cancer operation at a HVH.

CONCLUSIONS

Patients of clinicians with linkages to HVHs are more likely to have their colorectal cancer operations at these hospitals. These findings suggest that policy interventions targeting clinician relationships are an important step in providing equitable surgical care.

An optimized method for the isolation of urinary extracellular vesicles for molecular phenotyping: detection of biomarkers for radiation exposure

Background

Urinary extracellular vesicles (EVs) are a source of biomarkers with broad potential applications across clinical research, including monitoring radiation exposure. A key limitation to their implementation is minimal standardization in EV isolation and analytical methods. Further, most urinary EV isolation protocols necessitate large volumes of sample. This study aimed to compare and optimize isolation and analytical methods for EVs from small volumes of urine.

Methods

3 EV isolation methods were compared: ultracentrifugation, magnetic bead-based, and size-exclusion chromatography from 0.5 mL or 1 mL of rat and human urine. EV yield and mass spectrometry signals (Q-ToF and Triple Quad) were evaluated from each method. Metabolomic profiling was performed on EVs isolated from the urine of rats exposed to ionizing radiation 1-, 14-, 30- or 90-days post-exposure, and human urine from patients receiving thoracic radiotherapy for the treatment of lung cancer pre- and post-treatment.

Results

Size-exclusion chromatography is the preferred method for EV isolation from 0.5 mL of urine. Mass spectrometry-based metabolomic analyses of EV cargo identified biochemical changes induced by radiation, including altered nucleotide, folate, and lipid metabolism. We have provided standard operating procedures for implementation of these methods in other laboratories.

Conclusions

We demonstrate that EVs can be isolated from small volumes of urine and analytically investigated for their biochemical contents to detect radiation induced metabolomic changes. These findings lay a groundwork for future development of methods to monitor response to radiotherapy and can be extended to an array of molecular phenotyping studies aimed at characterizing EV cargo.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03414-7.

Prostate Cancer Treatment with Pencil Beam Proton Therapy Using Rectal Spacers sans Endorectal Balloons

Purpose

Proton beam radiotherapy (PBT) has been used for the definitive treatment of localized prostate cancer with low rates of high-grade toxicity and excellent patient-reported quality-of-life metrics. Technological advances such as pencil beam scanning (PBS), Monte Carlo dose calculations, and polyethylene glycol gel rectal spacers have optimized prostate proton therapy. Here, we report the early clinical outcomes of patients treated for localized prostate cancer using modern PBS–PBT with hydrogel rectal spacing and fiducial tracking without the use of endorectal balloons.

Materials and Methods

This is a single institutional review of consecutive patients treated with histologically confirmed localized prostate cancer. Prior to treatment, all patients underwent placement of fiducials into the prostate and insertion of a hydrogel rectal spacer. Patients were typically given a prescription dose of 7920 cGy at 180 cGy per fraction using a Monte Carlo dose calculation algorithm. Acute and late toxicity were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE), version 5. Biochemical failure was defined using the Phoenix definition.

Results

From July 2018 to April 2020, 33 patients were treated (median age, 75 years). No severe acute toxicities were observed. The most common acute toxicity was urinary frequency. With a median follow-up of 18 months, there were no high-grade genitourinary late toxicities; however, one grade 3 gastrointestinal toxicity was observed. Late erectile dysfunction was common. One treatment failure was observed at 21 months in a patient treated for high-risk prostate cancer.

Conclusion

Early clinical outcomes of patients treated with PBS–PBT using Monte Carlo–based planning, fiducial placement, and rectal spacers sans endorectal balloons demonstrate minimal treatment-related toxicity with good oncologic outcomes. Rectal spacer stabilization without the use of endorectal balloons is feasible for the use of PBS–PBT.

TGFβ Drives Metabolic Perturbations during Epithelial Mesenchymal Transition in Pancreatic Cancer: TGFβ Induced EMT in PDAC

Simple Summary

Pancreatic cancer is an aggressive disease with most patients diagnosed at late stages resulting in poor outcomes. While it is known that pancreatic tumor cells undergo epithelial to mesenchymal transition, the metabolic alterations accompanying that transition are not characterized. This study leveraged a metabolomics approach to understand the small molecule and biochemical perturbations that can be targeted for designing strategies for improving outcomes in pancreatic cancer.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy wherein a majority of patients present metastatic disease at diagnosis. Although the role of epithelial to mesenchymal transition (EMT), mediated by transforming growth factor beta (TGFβ), in imparting an aggressive phenotype to PDAC is well documented, the underlying biochemical pathway perturbations driving this behaviour have not been elucidated. We used high-resolution mass spectrometry (HRMS) based molecular phenotyping approach in order to delineate metabolic changes concomitant to TGFβ-induced EMT in pancreatic cancer cells. Strikingly, we observed robust changes in amino acid and energy metabolism that may contribute to tumor invasion and metastasis. Somewhat unexpectedly, TGFβ treatment resulted in an increase in intracellular levels of retinoic acid (RA) that in turn resulted in increased levels of extracellular matrix (ECM) proteins including fibronectin (FN) and collagen (COL1). These findings were further validated in plasma samples obtained from patients with resectable pancreatic cancer. Taken together, these observations provide novel insights into small molecule dysregulation that triggers a molecular cascade resulting in increased EMT-like changes in pancreatic cancer cells, a paradigm that can be potentially targeted for better clinical outcomes.

Precise Measurement of the D^{0} and D^{+} Lifetimes at Belle II

We report a measurement of the D^{0} and D^{+} lifetimes using D^{0}→K^{-}π^{+} and D^{+}→K^{-}π^{+}π^{+} decays reconstructed in e^{+}e^{-}→cc[over ¯] data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The data, collected at center-of-mass energies at or near the ϒ(4S) resonance, correspond to an integrated luminosity of 72  fb^{-1}. The results, τ(D^{0})=410.5±1.1(stat)±0.8(syst)  fs and τ(D^{+})=1030.4±4.7(stat)±3.1(syst)  fs, are the most precise to date and are consistent with previous determinations.

Abstract 478: Extracellular vesicle based multi-omics prediction model for the early detection of pancreatic cancer

Introduction: Pancreas cancer (PC) is projected to become the third leading cause of cancer deaths in the US, however there is no screening test in routine clinical use. A minimally invasive test for early detection of PC is a critical unmet clinical need. Extracellular vesicles (EVs) shed into the circulation include a diverse array of surface and cargo biomolecules that can be leveraged as biomarkers for the early detection of PC. We hypothesize that systemic molecular characterization of plasma EVs, secreted by latent yet progressing precursor lesions (PL) of the pancreas, may lead to the development of high accuracy classification algorithms for stratification of patients for the early detection of PC. Herein, we developed a liquid biopsy-based PACE assay (Pancreatic Cancer Exosomics) comprised of a multi-omics (proteomics, metabolomics, and lipidomics) biomarker panel.

Methods: To develop a functional EV-based multi-omics biomarker panel, we performed metabolomics, lipidomics and proteomics analysis of EVs from high quality pre-surgery, fasting plasma samples obtained from patients with early stage pancreatic cancer (IA, IB and IIA) (N= 60), normal control subjects without cancer (N = 50), patients diagnosed with pancreatitis (benign) (N= 39), and early stage colorectal cancer (N=30) as related disease cohorts. For selection of candidate biomarkers, we randomly divided 3/5th of the sample set as discovery and the remainder 2/5th as the test cohort. To consider the effect of potential correlation for predictors, we applied the elastic net penalty to generalized linear model (ELNET). A 100-fold cross-validation approach was used to determine tuning parameters and calibrate the prediction model in the discovery set.

Results: These analyses allowed us to develop a 12 analyte multi-omics panel that could discriminate early stage PC from normal controls (NC) with 98.2% accuracy (Specificity (SP) = 85.2% and Sensitivity (SN) = 71.5%) and 95.4% accuracy (SP = 92.8% and SN = 59.3%) for discovery and validation sets, respectively. A unique aspect of the study design was the inclusion of control cohorts to eliminate non-specific markers. Furthermore, extensive clinical outcome data allowed us to develop multi-analyte predictors of overall survival and progression free survival with high accuracy. Validation of these findings using orthogonal methods is ongoing.

Conclusions: In summary, these preliminary data provide strong support for the development of a liquid biopsy-based EV biomarker panel for the early detection of PC. We believe the positive predictive value (PPV) of this panel can be further improved in conjunction with serum CA 19-9 that is in routine clinical use.

Citation Format: Yaoxiang Li, Keith Unger, Charles Hinzman, Meth Jayatilake, Anton Iliuk, Shivani Bansal, Michael Girgis, Partha Banerjee, John B. Tyburski, Todd Bauer, Amrita K. Cheema. Extracellular vesicle based multi-omics prediction model for the early detection of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 478.

Abstract 2740: Effect of pancreatic cancer cell derived extracellularvesicles on the tumor microenvironment

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one amongst the most lethal malignancies, with a 5 year survival rate of &lt;10%.While the tumor microenvironment in PDAC is highly immunosuppressive, little is known about the mechanisms of immune invasion leading to rapid tumor progression. Hence, in-depth exploration of early cellular and molecular drivers of PDAC is desirable for early and precise diagnosis and to identify new biological targets for developing new therapies. Extracellular vesicles (EVs) are nanometer sized particles that are shed by most tissues/organs and are known to be important mediators of intercellular signaling and molecular transfer. We hypothesized that pancreatic cancer derived EVs may play an important role in mediating the interactions among the tumor and surrounding microenvironment (TME). Given that tumor-associated macrophages (TAMs) are integral components of the TME that can promote tumor progression, tumor invasion, and intravasation to other parts of the body, this study is focused on investigating the role of PDAC derived EVs in macrophages polarization, which in turn would impact tumor cell proliferation and invasion.

Results: EVs were isolated from 6 pancreatic cancer (PaCa) and 2 normal established pancreatic epithelial cell lines. EVs were characterized using nanoparticle tracking (NTA) and immunoblot analysis. LC-MS/MS based shotgun proteomics analyses of EVs revealed that PaCa cell line derived EVs were significantly enriched in potentially immunomodulatory proteins such as S100 calcium-binding protein A4 (S100A4) and human leukocyte antigen-B (HLA-B). However, PaCa cell EVs had significantly less MHC-class-I-related chain A (MICA), a protein important for proper human leukocyte antigen (HLA) function, as compared to normal pancreatic epithelial cell derived EVs. These data suggest that PaCa derived EVs may influence immunomodulation and macrophage function within the tumor microenvironment thereby strengthening our hypothesis. Further experimental studies aimed at delineating the precise mechanism of action of EVs in macrophage polarization is ongoing.

Conclusions: Our finding suggests significant difference among the molecular composition of PaCa derived cargos as compared to and normal cells derived EVs that could be useful in furthering our understanding about pancreatic cancer etiology. Furthermore, the novel insights obtained from these studies may augment the development of biomarkers that can be used for early detection of the disease and improved therapeutics to improve clinical outcomes.

Citation Format: Baldev Singh, Charles Hinzman, Edina Wang, Anton Iliuk, Jose Trevino, Keith Unger, Partha Banerjee, Amrita K. Cheema. Effect of pancreatic cancer cell derived extracellularvesicles on the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2740.

Search for Axionlike Particles Produced in e^{+}e^{-} Collisions at Belle II

We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e^{+}e^{-}→γa, a→γγ in the mass range 0.2<m_{a}<9.7  GeV/c^{2} using data corresponding to an integrated luminosity of (445±3)  pb^{-1}. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength g_{aγγ} of ALPs to photons at the level of 10^{-3}  GeV^{-1}. The limits are the most restrictive to date for 0.2<m_{a}<1  GeV/c^{2}.

A Prospective Study of Early Radiation Associated Cardiac Toxicity Following Neoadjuvant Chemoradiation for Distal Esophageal Cancer

Purpose: This study aimed to prospectively evaluate the early effects of radiation on cardiac structure and function following neoadjuvant chemoradiation for distal esophageal cancer. Methods and Materials: Patients with non-metastatic esophageal cancer who were suitable for tri-modality therapy with concurrent chemoradiotherapy followed by esophagectomy were enrolled. Cardiac magnetic resonance imaging (CMR) was obtained at baseline and 3-5 months following completion of chemoradiation. Standardized myocardial segmentation was used to identify regions on post-treatment CMR with new T2 signal or late gadolinium enhancement (LGE). Pre and post-treatment cardiac function was assessed with quantitative end points including left ventricle end-systolic volume (LSESV). Serum biomarkers of cardiac damage including troponin I, CRP, and BNP were collected at baseline and time of follow-up CMR. Results: A total of 11 patients were enrolled from 2016 to 2018. Patients had clinical stage T2 (18%) and T3 (82%) disease with clinical N0 (27%) and N1 (73%) nodal stage. All patients completed baseline CMR and completed chemoradiotherapy. One patient did not complete follow-up CMR or serum biomarkers and was excluded from the analysis. The median time from completion of chemoradiation to follow-up CMR was 3.9 months. Three out of 10 patients (30%) developed new structural findings of myocardial fibrosis and/or reversible ischemia involving the basal and mid-inferior and inferoseptal walls. In these three patients, the LVESV was significantly increased from baseline following radiation. There were no differences in other quantitative end points or serum biomarkers between the patients with myocardial damage and those without. Conclusions: Our study is the first to our knowledge to prospectively demonstrate radiation associated structural and functional heart damage as early as 3 months following neoadjuvant chemoradiation for distal esophageal cancer. Given the early onset of this subclinical heart damage, strategies should be developed to identify patients at risk for future clinically significant heart toxicity.

Plasma metabolite biomarkers predictive of radiation induced cardiotoxicity

PURPOSE

Although advancements in cancer treatments using radiation therapy (RT) have led to improved outcomes, radiation-induced heart disease (RIHD) remains a significant source of morbidity and mortality in survivors of cancers in the chest. Currently, there are no diagnostic tests in clinical use due to a lack of understanding of the natural history and mechanisms of RIHD development. Few studies have examined the utility of using metabolomics to prospectively identify cancer survivors who are at risk of developing cardiotoxicity.

METHODS

We analyzed plasma and left ventricle heart tissue samples collected from a cohort of male Sprague Dawley (SD) rats that were either sham irradiated or received fractionated doses (9 Gy per day × 5 days) of targeted X-ray radiation to the heart. Metabolomic and lipidomic analyses were utilized as a correlative approach for delineation of novel biomarkers associated with radiation-induced cardiac toxicity. Additionally, we used high-resolution mass spectrometry to examine the metabolomic profiles of plasma samples obtained from patients receiving high dose thoracic RT for esophageal cancer.

RESULTS

Metabolic alterations in the rat model and patient plasma profiles, showed commonalities of radiation response that included steroid hormone biosynthesis and vitamin E metabolism. Alterations in patient plasma profiles were used to develop classification algorithms predictive of patients at risk of developing RIHD.

CONCLUSION

Herein, we report the feasibility of developing a metabolomics-based biomarker panel that is associated with adverse outcomes of cardiac function in patients who received RT for the treatment of esophageal cancer.

Search for an Invisibly Decaying Z^{'} Boson at Belle II in e^{+}e^{-}→μ^{+}μ^{-}(e^{±}μ^{∓}) Plus Missing Energy Final States

Theories beyond the standard model often predict the existence of an additional neutral boson, the Z^{'}. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z^{'} in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'} and of a lepton-flavor-violating Z^{'} in e^{+}e^{-}→e^{±}μ^{∓}Z^{'}. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an L_{μ}-L_{τ} theory, into upper limits on the Z^{'} coupling constant at the level of 5×10^{-2}-1 for M_{Z^{'}}≤6  GeV/c^{2}.

Immunotherapy and radiation therapy for gastrointestinal malignancies: hope or hype?

Immunotherapy represents the newest pillar in cancer care. Although there are increasing data showing the efficacy of immunotherapy there is a spectrum of response across unselected populations of cancer patients. In fact, response rates can be poor even among patients with immunogenic tumors for reasons that remain poorly understood. A promising clinical strategy to improve outcomes, which is supported by an abundance of preclinical data, is combining immunotherapy with radiation therapy. Here we review the existing evidence and future directions for combining immunotherapy and radiation therapy for patients with gastrointestinal cancers.

Management of Cardiovascular Disease in Women With Breast Cancer

Cardio-oncology is a rapidly developing field which seeks to improve patient outcomes through enhanced clinical and research collaboration across the disciplines of oncology and cardiology. Breast cancer (BC) is the most common cancer diagnosis among women in the United States and, as decades of research have resulted in decreased mortality rates, there has been an increasing focus on reducing short- and long-term treatment toxicity and improving morbidity among survivors. Preexisting or emergent cardiovascular disease in a patient with BC requires a multidisciplinary, team-based approach to balance the need for curative cancer treatment while preventing increased cardiovascular disease morbidity and mortality. Given the overlap in risk factors for BC and cardiovascular disease, such as smoking, sedentary lifestyle, and obesity, there are opportunities for cardiovascular disease prevention and detection before, during, and after BC treatment. Cardiology providers also play an important role in preventing, diagnosing, and treating cardiac dysfunction and other cardiovascular complications that may develop as a result of BC treatment. A number of recent clinical practice guidelines address approaches to cardiotoxicity, however, they focus on specific agents or treatment modality, rather than on collaborative disease management. In this review we present cardiovascular concerns associated with contemporary, multimodality BC treatment and illustrate how current guideline recommendations apply to clinical cardiology and oncology questions. We provide a cardio-oncology team-based approach to cardiovascular assessment and management of patients with BC from diagnosis through treatment and in survivorship.

Abstract 4863: Discovery of novel metabolomic plasma biomarkers predictive of radiation induced cardiac toxicity

Introduction: Although advancements in cancer treatment have led to increased survivorship, radiation induced heart disease (RIHD) remains a major source of acute and long term morbidity and mortality for cancer survivors, for which there are no diagnostic tests in routine clinical use due to lack efficacy or excessive cost. Several studies have documented RIHD; however, none of these investigations have examined the utility of using metabolomics to prospectively identify cancer survivors who are at risk of cardiotoxicity. The overarching goal of this pilot study is to determine whether biomolecules secreted in the circulation by latent yet developing cardiotoxic processes can be leveraged for predicting risk of cardiac dysfunction in cancer survivors.

Approach: We used metabolomics/lipidomics analysis, an emerging field that provides information on biological perturbations based on relative changes in the plasma levels of endogenous metabolites, for a retrospective outcome analysis study. Patients treated at GUH with radiation therapy (RT) for locally advanced esophageal cancer (n = 11 x 3 time points), who underwent serial cardiac MRI’s were selected. We identified a subset of patients who developed radiation related heart ischemia and fibrosis in the inferior/ basal segment of the heart associated with the high dose region, as well as associated cardiac functional impairments (n = 6 x 3 time points). We also analyzed plasma and cardiac tissue samples from groups male Sprague Dawley (SD) rats that were either sham irradiated or received fractionated doses (9 Gy per day x 5 days) of targeted X-ray radiation to the heart. Metabolomic analysis was used as a correlative approach for delineation of novel biomarkers associated with radiation induced cardiac toxicity.

Results: Global metabolomics and lipidomics analyses have yielded important data for developing classification algorithms with high predictive accuracy. We are in the process of performing statistical analyses to determine the sensitivity and specificity of the resultant panel, and any influence provided by age and gender on the predictive performance of the biomarker panel. These data will be presented at the AACR meeting.

Conclusion: Cardiac dysfunction following cancer therapy leads to significant morbidity and mortality. While our cohort includes esophageal cancer patients, we believe the cardiac toxicities detailed previously are applicable to other patient populations receiving high dose thoracic radiation therapy. We believe findings from this study are of significant interest to the scientific community since there are critical gaps in knowledge related to mechanisms of cardiac injury, clinical prediction, screening, prevention, and treatment.

Supported by Cancer Center Support Grant (CCSG/NCI/NIH) and funding Ruesch Foundation

Citation Format: Keith Unger, Michael Girgis, Meena Rajagopal, Yeline Ceh, Meth Jayatilake, Yaoxiang Li, Amrita K. Cheema. Discovery of novel metabolomic plasma biomarkers predictive of radiation induced cardiac toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4863.

Five-Fraction Stereotactic Body Radiation Therapy (SBRT) and Chemotherapy for the Local Management of Metastatic Pancreatic Cancer

BACKGROUND

The majority of patients with pancreatic cancer are diagnosed with metastatic disease at presentation. Nevertheless, local progression is responsible for up to 30% of deaths and can lead to significant morbidity. As a consequence, further exploration of effective methods of local control and palliation is essential. Stereotactic body radiation therapy (SBRT) is a widely utilized technique for the treatment of localized pancreatic cancer. Here, we report our experience with SBRT and chemotherapy for the local treatment of the metastatic patient population.

METHODS

This single institution retrospective review analyzed 20 patients with pathologically diagnosed metastatic adenocarcinoma of the pancreas. All patients underwent fiducial placement under endoscopic ultrasound (EUS) guidance. SBRT was delivered in five fractions to a total dose of 25 to 30 Gy. Patients received concurrent (given within 1 week of the start of SBRT) or sequential chemotherapy. Local tumor control was evaluated using Response Evaluation Criteria in Solid Tumors. Toxicity was graded using Common Terminology Criteria for Adverse Events version 4.03. Local control and overall survival were reported using the Kaplan-Meier method.

RESULTS

Patient median age was 64 years, and the median pre-treatment Eastern Cooperative Oncology Group performance status was 1. All patients received chemotherapy and half of the patients (10 of 20) received concurrent chemotherapy with folinic acid, fluorouracil, and oxaliplatin or fluorouracil, leucovorin, irinotecan, and oxaliplatin. Nearly all patients (19 of 20) received post-SBRT chemotherapy. Median time from pathological diagnosis to SBRT was 3.9 months. The twelve-month local control and overall survival were 43 and 53%, respectively. However, in patients with planning target volume (PTV) targets smaller than the population median, the 12-month local control was 78%. Median time to local progression (17.8 vs. 3.0 months, p = 0.02) and overall survival (24.9 vs. 8.8, p = 0.001) were also significantly improved in this smaller PTV cohort. Though not statistically significant, there was a trend towards improvement in local control (17.8 vs. 4.3 months, p = 0.17) and overall survival (16.7 vs. 9.7 months, p = 0.087) for those who received concurrent versus sequential chemotherapy, respectively. Lastly, there were no reported grade 3-5 late toxicities.

CONCLUSIONS

As systemic therapies improve, the local management of pancreatic cancer will become increasingly important. Here, we report significantly improved local control with SBRT of smaller PTV tumors with concurrent chemotherapy. Five-fraction SBRT offers a quick and effective modality of local tumor control with minimal toxicity in the metastatic pancreatic cancer population.

Metabolomics based predictive classifier for early detection of pancreatic ductal adenocarcinoma

The availability of robust classification algorithms for the identification of high risk individuals with resectable disease is critical to improving early detection strategies and ultimately increasing survival rates in PC. We leveraged high quality biospecimens with extensive clinical annotations from patients that received treatment at the Medstar-Georgetown University hospital. We used a high resolution mass spectrometry based global tissue profiling approach in conjunction with multivariate analysis for developing a classification algorithm that would predict early stage PC with high accuracy. The candidate biomarkers were annotated using tandem mass spectrometry. We delineated a six metabolite panel that could discriminate early stage PDAC from benign pancreatic disease with >95% accuracy of classification (Specificity = 0.85, Sensitivity = 0.9). Subsequently, we used multiple reaction monitoring mass spectrometry for evaluation of this panel in plasma samples obtained from the same patients. The pattern of expression of these metabolites in plasma was found to be discordant as compared to that in tissue. Taken together, our results show the value of using a metabolomics approach for developing highly predictive panels for classification of early stage PDAC. Future investigations will likely lead to the development of validated biomarker panels with potential for clinical translation in conjunction with CA-19-9 and/or other biomarkers.

Metabolomic biomarkers of pancreatic cancer: a meta-analysis study

Pancreatic cancer (PC) is an aggressive disease with high mortality rates, however, there is no blood test for early detection and diagnosis of this disease. Several research groups have reported on metabolomics based clinical investigations to identify biomarkers of PC, however there is a lack of a centralized metabolite biomarker repository that can be used for meta-analysis and biomarker validation. Furthermore, since the incidence of PC is associated with metabolic syndrome and Type 2 diabetes mellitus (T2DM), there is a need to uncouple these common metabolic dysregulations that may otherwise diminish the clinical utility of metabolomic biosignatures. Here, we attempted to externally replicate proposed metabolite biomarkers of PC reported by several other groups in an independent group of PC subjects. Our study design included a T2DM cohort that was used as a non-cancer control and a separate cohort diagnosed with colorectal cancer (CRC), as a cancer disease control to eliminate possible generic biomarkers of cancer. We used targeted mass spectrometry for quantitation of literature-curated metabolite markers and identified a biomarker panel that discriminates between normal controls (NC) and PC patients with high accuracy. Further evaluation of our model with CRC, however, showed a drop in specificity for the PC biomarker panel. Taken together, our study underscores the need for a more robust study design for cancer biomarker studies so as to maximize the translational value and clinical implementation.

Radiation therapy for hepatobiliary malignancies

Hepatobiliary malignancies represent a heterogeneous group of diseases, which often arise in a background of underlying hepatic dysfunction complicating their local management. Surgical resection continues to be the standard of care for hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC); unfortunately the majority of patients are inoperable at presentation. The aggressiveness of these lesions makes locoregional control of particular importance. Historical experience with less sophisticated radiotherapy resulted in underwhelming efficacy and oftentimes prohibitive liver toxicity. However, with the advent of extremely conformal and precise radiotherapy delivery, dose escalation to the tumor with sparing of surrounding normal tissue has yielded notable improvements in efficacy for this modality of treatment. Dose escalation has come in a variety of forms most notably as stereotactic body radiation therapy (SBRT) and hypofractionated proton therapy. As radiation techniques continue to improve, their proper incorporation into the local management of hepatobiliary malignancies will be paramount in improving the prognosis of what is a grave diagnosis.

Clinical outcomes of gastrointestinal brain metastases treated with radiotherapy

Background

Brain metastases of gastrointestinal origin are a rare occurrence. Radiation therapy (RT) in the form of stereotactic radiosurgery (SRS) or whole brain radiation therapy (WBRT) is an effective established treatment modality in either the definitive or adjuvant setting. The aim of this study is to assess the long-term clinical outcomes of patients with gastrointestinal (GI) brain metastases treated with SRS or WBRT.

Methods

In this single institutional retrospective review, we detail the outcomes of patients diagnosed with metastatic brain tumors from an adenocarcinoma gastrointestinal primary. Patients were treated using stereotactic radiosurgery or whole brain radiation therapy. Initial site control (defined as lesions visualized on imaging at time of treatment), new site control (defined as new intracranial lesions visualized on follow-up imaging), and overall survival were calculated using the Kaplan-Meier method.

Results

Thirty-three patients were treated from August 2008 to December 2015. Primary malignancy locations were as follows: 18 colon, 6 esophagus, 4 rectum, 5 other. Median total dose delivered was 25 Gy (18–35 Gy) in a median of 4 fractions for SRS and 30 Gy (10.8–40 Gy) in 10 fractions for WBRT. Crude initial site control at last radiographic follow-up was 64.3% after SRS and 41.7% after WBRT. Eleven of the 28 brain lesions (39.3%) treated with SRS had resection of the SRS-treated lesion prior to radiation therapy. Five of the twelve patients (41.7%) undergoing WBRT underwent cranial resection prior to radiation therapy. Crude new site control at last radiographic follow-up was 46.4% after SRS and 83.3% after WBRT. Kaplan-Meier analysis of overall survival did not show any statistically significant difference between WBRT and SRS (p = 0.424). Median overall survival for SRS patients was 5.2 months (0.5–57.5) and for WBRT patients 4.4 months (0–15). Kaplan-Meier analysis of new site control was significantly improved with WBRT versus SRS (p = 0.017). Total dose, treatment with WBRT, and active extracranial disease were statistically significant on multivariate analysis for new site control (p < 0.05).

Conclusions

Survival and intracranial disease control are poor following RT for brain metastases from GI primaries. In this small series, outcomes are worse than published series for other primary malignancies metastatic to the brain and further research into methods of local control improvement is warranted. Future studies should explore the utility of dose escalation or radiosensitization in this patient population.

Yttrium-90 radioembolization for colorectal cancer liver metastases in KRAS wild-type and mutant patients: Clinical and ccfDNA studies

Patients with unresectable, chemo-refractory colorectal cancer liver metastases (CRCLM) have limited local treatment options. We report our institutional experience on the efficacy of resin-based yttrium-90 (⁹⁰Y) radioembolization for the treatment of CRCLM and our findings on associated circulating cell-free DNA (ccfDNA) studies. A total of 58 patients treated with ⁹⁰Y for CRCLM at the Medstar Georgetown University Hospital had a median survival of 6 months [95% confidence interval (CI), 4.55–7.45 months] after treatment, with a 12-month survival rate of 33%. The median survival from treatment stratified by mutational status was longer in the wild-type (WT) as compared to the KRAS mutant patients at 7 vs. 5 months, but did not achieve statistical significance (p=0.059). Median tumor local control duration after ⁹⁰Y treatment was 2 months (95% CI, 0.34–3.66 months) for the entire cohort and was longer in the WT vs. the mutant patients (2 vs. 1 month, respectively, p=0.088). Plasma was prospectively collected from a subset of 9 patients both before and after single lobe treatment, and ccfDNA concentration and fragmentation index (FI) were measured using quantitative PCR and atomic-force microscopy (AFM). In the WT and KRAS mutant patients, DNA FI was reduced from a median of 0.73–0.65 after treatment. A reduction in DNA FI after single lobe treatment was associated with an improved overall survival (p=0.046). Analysis by AFM of paired pre- and post-treatment samples from KRAS mutant and WT patients revealed a larger average decrease in fragment size in the WT patients (p=0.013). ⁹⁰Y radioembolization extends local control for CRCLM, however, KRAS mutant tumors may be more radio-resistant to treatment. Changes in the FI of patients following treatment were noted and may be evaluated in a larger study for relevance as a biomarker of response.

Incorporating Yttrium-90 trans-arterial radioembolization (TARE) in the treatment of metastatic pancreatic adenocarcioma: a single center experience

BACKGROUND

The purpose of this retrospective study was to evaluate the efficacy of incorporating trans-arterial radioembolization (TARE) with systemic chemotherapy in the treatment of liver-dominant metastatic pancreatic ductal adenocarcinoma, with the aim of destroying liver metastases and improving patient outcomes.

METHODS

We retrospectively evaluated 16 patients with liver-dominant metastatic pancreatic ductal adenocarcinoma who underwent TARE between February 2012 and August 2015; 15 of these patients also underwent concurrent systemic chemotherapy. Patient outcomes were assessed using Response Evaluation Criteria In Solid Tumors (RECIST), Version 1.1 and included disease response, median overall survival from the time of diagnosis of metastatic disease, and median overall survival following receipt of TARE. Treatment-related adverse events were assessed using Common Terminology Criteria for Adverse Events (CTCAE), Version 4.03.

RESULTS

The median overall survival from the time of diagnosis of metastatic disease and following receipt of TARE was 22.0 and 12.5 months, respectively. Overall and liver specific disease response were assessed for 13 patients with follow-up imaging available at the time of study (range 2-13 weeks post TARE). Four patients (31 %) demonstrated partial response and five patients (38 %) had stable disease in the liver at follow-up. One patient developed grade 3 elevation of total bilirubin three months post-treatment and another patient developed radiation cholecystitis directly following TARE. No treatment-related grade 4 or 5 toxicities were seen.

CONCLUSION

TARE can be safely combined with systemic chemotherapy for the treatment of liver-dominant metastatic pancreatic cancer. Patient outcomes following this treatment strategy are promising but prospective evaluations are needed to validate these preliminary findings.

Neoadjuvant Combined-Modality Therapy for Locally Advanced Rectal Cancer and Its Future Direction

Rectal cancer treatment presents a challenge, and its optimal management requires a multidisciplinary approach involving surgical, medical, and radiation oncologists. Advances in surgical techniques, radiotherapy, and medical imaging technology have transformed the therapeutic landscape and have led to substantial improvements in both local disease control and patient survival. The currently established standard of care for patients with locally advanced rectal cancer involves preoperative (neoadjuvant) concurrent radiotherapy and infusional fluorouracil-based or oral capecitabine-based chemotherapy, also known as chemoradiotherapy (CRT), followed by surgery. Surgery is often followed by adjuvant chemotherapy. Here we discuss the evolution of standard therapy for rectal cancer patients and the use of preoperative CRT for the treatment of locally advanced disease. Treatment schemes that have attempted to broaden the horizons of standard therapy include the use of induction chemotherapy and "watch-and-wait" approaches. We examine several novel trials using these and other treatment approaches, which may eventually lead to better patient selection and the avoidance of overtreatment and unnecessary adverse effects.

Stereotactic Accelerated Partial Breast Irradiation for Early-Stage Breast Cancer: Rationale, Feasibility, and Early Experience Using the CyberKnife Radiosurgery Delivery Platform

PURPOSE

The efficacy of accelerated partial breast irradiation (APBI) utilizing brachytherapy or conventional external beam radiation has been studied in early-stage breast cancer treated with breast-conserving surgery. Data regarding stereotactic treatment approaches are emerging. The CyberKnife linear accelerator enables excellent dose conformality to target structures while adjusting for target and patient motion. We report our institutional experience on the technical feasibility and rationale for stereotactic accelerated partial breast irradiation (SAPBI) delivery using the CyberKnife radiosurgery system.

METHODS

Ten patients completed CyberKnife SAPBI (CK-SAPBI) in 2013 at Georgetown University Hospital. Four gold fiducials were implanted around the lumpectomy cavity prior to treatment under ultrasound guidance. The synchrony system tracked intrafraction motion of the fiducials. The clinical target volume was defined on contrast enhanced CT scans using surgical clips and post-operative changes. A 5 mm expansion was added to create the planning treatment volume (PTV). A total dose of 30 Gy was delivered to the PTV in five consecutive fractions. Target and critical structure doses were assessed as per the National Surgical Adjuvant Breast and Bowel Project B-39 study.

RESULTS

At least three fiducials were tracked in 100% of cases. The Mean treated PTV was 70 cm(3) and the mean prescription isodose line was 80%. Mean dose to target volumes and constraints are as follows: 100% of the PTV received the prescription dose (PTV30). The volume of the ipsilateral breast receiving 30 Gy (V30) and above 15 Gy (V > 15) was 14 and 31%, respectively. The ipsilateral lung volume receiving 9 Gy (V9) was 3%, and the contralateral lung volume receiving 1.5 Gy (V1.5) was 8%. For left-sided breast cancers, the volume of heart receiving 1.5 Gy (V1.5) was 31%. Maximum skin dose was 36 Gy. At a median follow-up of 1.3 years, all patients have experienced excellent/good breast cosmesis outcomes, and no breast events have been recorded.

CONCLUSION

CyberKnife stereotactic accelerated partial breast irradiation is an appealing technique for partial breast irradiation offering improvements over existing APBI techniques. Our early findings indicate that CK-SAPBI delivered in five daily fractions is feasible, well tolerated, and is a reliable platform for delivering APBI.

Outcomes and Predictors of Toxicity after Selective Internal Radiation Therapy Using Yttrium-90 Resin Microspheres for Unresectable Hepatocellular Carcinoma

Purpose

We sought to report outcomes and toxicity in patients with hepatocellular carcinoma (HCC) who received resin yttrium-90 selective internal radiation therapy (⁹⁰Y-SIRT) and to identify factors associated with declining liver function.

Methods

Patients treated with ⁹⁰Y-SIRT were retrospectively evaluated. Radiographic response was assessed using RECIST 1.1. Median liver progression-free survival (LPFS) and overall survival (OS) were calculated using the Kaplan–Meier method. Bivariate analysis was used to examine associations between change in Child-Pugh (CP) score/class and patient characteristics and treatment parameters.

Results

Twenty-seven patients with unresectable HCC underwent SIRT, 52% were CP Class A, 48% were Class B, 11% were BCLC stage B, and 89% were stage C. Forty-four percent of patients had portal vein thrombus at baseline. One-third of patients received bilobar treatment. Median activity was 32.1 mCi (range 9.18–43.25) and median-­absorbed dose to the liver was 39.6 Gy (range 13.54–67.70). Median LPFS and OS were 2.5 and 11.7 months, respectively. Three-month disease control rate was 63 and 52% in the target lesions and whole liver, respectively. New onset or worsened from baseline clinical toxicities were confined to Grade 1–2 events. However, new or worsened Grade 3–4 laboratory toxicities occurred in 38% of patients at 3 months and 43% of patients at 6 months following SIRT (six had lymphocytopenia, three had hypoalbuminemia, and two had transaminasemia). After 3 months, six patients had worsened in CP score and five had worsened in class from baseline. After 6 months, four patients had worsened in CP score and one had worsened in class from baseline. Pretreatment bilirubinemia was associated with a 2+ increase in CP score within 3 months (P = 0.001) and 6 months (P = 0.039) of ⁹⁰Y-SIRT. Pretreatment transaminasemia and bilirubinemia were associated with increased CP class within 3 months of SIRT (P = 0.021 and 0.009, respectively).

Conclusion

⁹⁰Y-SIRT was well-tolerated in patients with unresectable HCC, with no Grade 3–4 clinical toxicities. However, Grade 3–4 laboratory toxicities and worsened CP scores were more frequent. HCC patients with pretreatment bilirubinemia or transaminasemia may be at higher risk of experiencing a decline in liver function following ⁹⁰Y-SIRT.