Prospective Trial of Functional Lung Avoidance Radiation Therapy for Lung Cancer: Quality of Life Report

PURPOSE

A novel form of lung function imaging has been developed that uses 4-dimensional computed tomography (4DCT) data to generate lung ventilation images (4DCT-ventilation). Functional avoidance uses 4DCT-ventilation to reduce doses to functional lung with the aim of reducing pulmonary side effects. A phase 2, multicenter 4DCT-ventilation functional avoidance clinical trial was completed. The purpose of this work was to quantify changes in patient-reported outcomes (PROs) for patients treated with functional avoidance and determine which metrics are predictive of PRO changes.

MATERIALS AND METHODS

Patients with locally advanced lung cancer receiving curative-intent radiation therapy were accrued. Each patient had a 4DCT-ventilation image generated using 4DCT data and image processing. PRO instruments included the Functional Assessment of Cancer Therapy-Lung (FACT-L) questionnaire administered pretreatment; at the end of treatment; and at 3, 6, and 12 months posttreatment. Using the FACT-Trial Outcome Index and the FACT-Lung Cancer Subscale results, the percentage of clinically meaningful declines (CMDs) were determined. A linear mixed-effects model was used to determine which patient, clinical, dose, and dose-function metrics were predictive of PRO decline.

RESULTS

Of the 59 patients who completed baseline PRO surveys. 83% had non-small cell lung cancer, with 75% having stage 3 disease. The median dose was 60 Gy in 30 fractions. CMD FACT-Trial Outcome Index decline was 46.3%, 38.5%, and 26.8%, at 3, 6, and 12 months, respectively. CMD FACT-Lung Cancer Subscale decline was 33.3%, 33.3%, and 29.3%, at 3, 6, and 12 months, respectively. Although an increase in most dose and dose-function parameters was associated with a modest decline in PROs, none of the results were significant (all P > .053).

CONCLUSIONS

The current work presents an innovative combination of use of functional avoidance and PRO assessment and is the first report of PROs for patients treated with prospective 4DCT-ventilation functional avoidance. Approximately 30% of patients had clinically significant decline in PROs at 12 months posttreatment. The study provides additional data on outcomes with 4DCT-ventilation functional avoidance.

Stereotactic Radiosurgery vs Conventional Radiotherapy for Localized Vertebral Metastases of the Spine: Phase 3 Results of NRG Oncology/RTOG 0631 Randomized Clinical Trial

Importance

Spine metastasis can be treated with high-dose radiation therapy with advanced delivery technology for long-term tumor and pain control.

Objective

To assess whether patient-reported pain relief was improved with stereotactic radiosurgery (SRS) as compared with conventional external beam radiotherapy (cEBRT) for patients with 1 to 3 sites of vertebral metastases.

Design, Setting, and Participants

In this randomized clinical trial, patients with 1 to 3 vertebral metastases were randomized 2:1 to the SRS or cEBRT groups. This NRG 0631 phase 3 study was performed as multi-institutional enrollment within NRG Oncology. Eligibility criteria included the following: (1) solitary vertebral metastasis, (2) 2 contiguous vertebral levels involved, or (3) maximum of 3 separate sites. Each site may involve up to 2 contiguous vertebral bodies. A total of 353 patients enrolled in the trial, and 339 patients were analyzed. This analysis includes data extracted on March 9, 2020.

Interventions

Patients randomized to the SRS group were treated with a single dose of 16 or 18 Gy (to convert to rad, multiply by 100) given to the involved vertebral level(s) only, not including any additional spine levels. Patients assigned to cEBRT were treated with 8 Gy given to the involved vertebra plus 1 additional vertebra above and below.

Main Outcomes and Measures

The primary end point was patient-reported pain response defined as at least a 3-point improvement on the Numerical Rating Pain Scale (NRPS) without worsening in pain at the secondary site(s) or the use of pain medication. Secondary end points included treatment-related toxic effects, quality of life, and long-term effects on vertebral bone and spinal cord.

Results

A total of 339 patients (mean [SD] age of SRS group vs cEBRT group, respectively, 61.9 [13.1] years vs 63.7 [11.9] years; 114 [54.5%] male in SRS group vs 70 [53.8%] male in cEBRT group) were analyzed. The baseline mean (SD) pain score at the index vertebra was 6.06 (2.61) in the SRS group and 5.88 (2.41) in the cEBRT group. The primary end point of pain response at 3 months favored cEBRT (41.3% for SRS vs 60.5% for cEBRT; difference, -19 percentage points; 95% CI, -32.9 to -5.5; 1-sided P = .99; 2-sided P = .01). Zubrod score (a measure of performance status ranging from 0 to 4, with 0 being fully functional and asymptomatic, and 4 being bedridden) was the significant factor influencing pain response. There were no differences in the proportion of acute or late adverse effects. Vertebral compression fracture at 24 months was 19.5% with SRS and 21.6% with cEBRT (P = .59). There were no spinal cord complications reported at 24 months.

Conclusions and Relevance

In this randomized clinical trial, superiority of SRS for the primary end point of patient-reported pain response at 3 months was not found, and there were no spinal cord complications at 2 years after SRS. This finding may inform further investigation of using spine radiosurgery in the setting of oligometastases, where durability of cancer control is essential.

Trial Registration

ClinicalTrials.gov Identifier: NCT00922974.

NIMG-67. MULTI-PARAMETRIC MRI-BASED MACHINE LEARNING ANALYSIS FOR PREDICTION OF NEOPLASTIC INFILTRATION AND RECURRENCE IN PATIENTS WITH GLIOBLASTOMA: UPDATES FROM THE MULTI-INSTITUTIONAL RESPOND CONSORTIUM

PURPOSE

Glioblastoma is extremely infiltrative with malignant cells extending beyond the enhancing rim where recurrence inevitably occurs, despite aggressive multimodal therapy. We hypothesize that important characteristics of peritumoral tissue heterogeneity captured and analyzed by multi-parametric MRI and artificial intelligence (AI) methods are generalizable in the updated multi-institutional ReSPOND (Radiomics Signatures for PrecisiON Diagnostics) consortium and predictive of neoplastic infiltration and future recurrence.

METHODS

We used the most recent update of the ReSPOND consortium to evaluate and further refine generalizability of our methods with different scanners and acquisition settings. 179 de novo glioblastoma patients with available T1, T1Gd, T2, T2-FLAIR, and ADC sequences at pre-resection baseline and after complete resection with subsequent pathology-confirmed recurrence were included. To establish generalizability of the predictive models, training and testing of the refined AI model was performed through Leave-One-Institution-Out-Cross-Validation schema. The multi-institutional cohort consisted of the Hospital of the University of Pennsylvania (UPenn, 124), Case Western Reserve University/University Hospitals (CWRU/UH, 27), New York University (NYU, 13), Ohio State University (OSU, 13), and University Hospital Río Hortega (RH, 2). Features extracted from pre-resection MRI were used to build the model predicting the spatial pattern of subsequent tumor recurrence. These predictions were evaluated against regions of pathology-confirmed post-resection recurrence.

RESULTS

Our model predicted the locations that later harbored tumor recurrence with overall odds ratio (99% CI)/AUC (99% CI), 12.0(11.8-12.2)/0.80(0.76-0.85), and per institute, CWRU/UH, 11.0(10.7-11.3)/0.80 (0.64-0.97); NYU, 7.0(6.7-7.3)/0.78(0.56-1.00); OSU, 18.3(17.5-19.1)/0.83(0.54-1.00); RH, 40.0(35.3-45.5)/0.93(0.00-1.00); UPenn, 8.00(7.7-8.3)/0.80(0.75-0.84).

CONCLUSION

This study provides extensive multi-institutional validated evidence that machine learning tools can identify peritumoral neoplastic infiltration and predict location of future recurrence, by decrypting the MRI signal heterogeneity in peritumoral tissue. Our analyses leveraged the unique dataset of the ReSPOND consortium, which aims to develop and validate AI-based biomarkers for individualized prediction and prognostication and establish generalizability in a multi-institutional setting.

NIMG-29. ASSOCIATION OF PARTIAL T2-FLAIR MISMATCH SIGN AND ISOCITRATE DEHYDROGENASE MUTATION IN WHO GRADE 4 GLIOMA/GLIOBLASTOMA: RESULTS FROM THE RESPOND CONSORTIUM

PURPOSE

T2-FLAIR mismatch (T2FM) is a highly specific imaging biomarker for isocitrate dehydrogenase (IDH) mutation in low-grade gliomas. Previous T2FM studies are inconsistent for glioblastoma (GBM)/grade-4 glioma, partly due to low IDH-mutation prevalence in high-grade gliomas. We leveraged a large multi-institutional GBM/grade-4 glioma cohort to analyze the association of partial T2FM and IDH-mutation (T2-hyperintense, FLAIR-hypointense, nonenhancing, nonedema).

METHODS

We analyzed preoperative MRI of 1500 pathologically confirmed GBM/grade-4 gliomas with known IDH-mutation status from the ReSPOND consortium, consisting of the following institutions (sample size): Ivy GBM Atlas Project (33), Catalan Institute of Oncology (132), Case Western Reserve University/University Hospitals (132), New York University (55), Ohio State University (25), University of Pennsylvania (641), University Hospital Río Hortega (16), Yonsei University Health System (118), The Cancer Imaging Archive (93), Thomas Jefferson University (48), Tata Memorial Hospital (22), University of Pittsburgh Medical Center (156), and Washington University School of Medicine in St. Louis (57). Sequences were co-registered to a common anatomic atlas. Continuous variables were compared by t-test and categorical variables by Χ 2-test.

RESULTS

71 (4.7%) were IDH-mutants, significantly younger (43±1 v. 62±12 years, p=5x10-37), and more likely to exhibit partial T2FM (20% v. 0.4%, p=1x10-43), frontal lobe predominance (68% v. 29%, p=7x10-12), nonenhancing components (T2/FLAIR-intermediate signal, nonedema; 45% v. 9%, p=1x10-22), and cystic components (smooth margins, no/minimal enhancement, homogeneous FLAIR suppression; 17% v. 3%, p=7x10-11) than IDH-wildtypes. 20 cases had partial T2FM (14 IDH-mutant, 6 IDH-wildtype). Sensitivity of partial T2FM for IDH-mutation was 19.7%, specificity 99.6%, positive predictive value 70%, and negative predictive value 96.1%. Subset analysis of 983 IDH-wildtypes with known MGMT methylation status (406 MGMT-hypermethylated) showed frontal lobe predominance was more common in MGMT-hypermethylated than MGMT-unmethylated (39.4% v. 24.3%, p=.02); other imaging characteristics did not significantly differ.

CONCLUSIONS

Partial T2FM is a highly specific imaging biomarker for IDH-mutation in GBM/grade-4 glioma.

NIMG-33. PROGNOSTIC STRATIFICATION OF DE NOVO GLIOBLASTOMA PATIENTS ACROSS 22 GEOGRAPHICALLY DISTINCT INSTITUTIONS: UPDATES FROM THE RESPOND CONSORTIUM

PURPOSE

Glioblastoma, IDH-wildtype, is the most common primary malignant adult brain tumor with median overall survival (OS) of ~14 months, with little improvement over the last 20 years. We hypothesize that AI-based integration of quantitative tumor characteristics, independent of acquisition protocol and equipment, can reveal accurate generalizable prognostic stratification. We seek an AI-based OS predictor using routine clinically acquired MRI sequences, quantitatively evaluated across institutions of the ReSPOND (Radiomics Signatures for PrecisiON Diagnostics) consortium.

METHODS

We identified a retrospective cohort of 2,293 diffuse glioma (IDH-wildtype/-NOS/-NEC) patients from 22 geographically distinct institutions across 3 continents, with preoperative structural MRI scans. The entire tumor burden was automatically segmented into 3 sub-compartments, i.e., enhancing, necrotic, peritumoral T2-FLAIR abnormality. We developed our AI predictor by multivariate integration of i)patient age, ii)tumor sub-compartment volume normalized to brain volume, iii)spatial distribution characteristics (tumor location, distance to the ventricles, and laterality), and iv)morphologic descriptors (major axes’ length, axes’ ratio, extent, and number of tumors). The AI predictor returns a continuous value between 0-1, defining short-, intermediate-, and long-survivors based on thresholds on the 25th and 75th percentiles. Leave-One-Site-Out-Cross-Validation was used to assess the generalizability of our stratification. Kaplan-Meier survival curves were computed for OS analysis and evaluated by a Cox proportional hazards model for statistical significance and hazard ratios.

RESULTS

Survival analysis yielded a hazard ratio of 2.07 (95%CI, 2.06-2.08, p-value= 4.8e-102) for patient stratification into short-, intermediate-, and long-survivors. Pearson correlation between the predicted and actual OS yielded an R= 0.49.

CONCLUSION

Multivariate integration of visually quantified tumor characteristics, agnostic to acquisition protocol/equipment, yields an accurate OS surrogate index. Validation of our AI model in the largest centralized glioblastoma imaging dataset, from the ReSPOND consortium, supports its generalizability across diverse patient populations and acquisition settings, potentially contributing to equitable improvements of personalized patient care.

Single-Fraction Celiac Plexus Radiosurgery: A Preliminary Proof-of-Concept Phase 2 Clinical Trial

BACKGROUND

Refractory epigastric/midback pain is associated with locally advanced abdominal malignancies, especially pancreatic cancer. The pain is caused by tumor infiltration of the celiac plexus, a nerve network attached to the abdominal aorta. Contemporary palliative approaches are often inadequate. We hypothesized that ablative radiation targeted to the celiac plexus would alleviate this pain.

METHODS AND MATERIALS

We performed a single-arm prospective clinical trial (ClinicalTrials.gov identifier: NCT02356406). Eligible and evaluable patients had celiac pain of at least 5 out of 10 on the Numerical Rating Scale, completed treatment per protocol, and had at least 1 posttreatment visit. The entire retroperitoneal celiac plexus was irradiated with a single 25-Gy fraction. The primary endpoint was change in the Numerical Rating Scale 3 weeks posttreatment. Toxic effects and pain interference (as measured with the Brief Pain Inventory) were secondary endpoints.

RESULTS

For our study, 31 patients signed consent, and, of these, 18 patients were treated and evaluable. Median age was 68 years (range, 51-79); 89% of the patients had pancreatic cancer; the median Eastern Cooperative Oncology Group performance status was 1; and the median interval from initial diagnosis to treatment was 9 months (range, 1-36), and, in this interval, patients received a median of 1 systemic treatment line (range, 0-3). Acute toxicity was limited to grade 1 to 2. Three weeks after treatment, 16 patients (84%) reported decreased celiac pain, with median pain level falling from 6 out of 10 (interquartile range [IQR], 5.0-7.5) at baseline to 3 out of 10 (IQR, 1.0-4.3); six weeks after treatment, the Numerical Rating Scale number fell further to 2.8 out of 10 (IQR, 0-3.3; both P < .005 vs baseline), including 4 patients who reported complete eradication of their celiac pain. Total daily morphine milligram equivalents decreased from 59 pretreatment to 50 at 3 weeks, and from 50 to 45 at 6 weeks. Significant improvement was seen in pain-interference scores.

CONCLUSIONS

Celiac plexus radiosurgery appears to alleviate cancer-related pain. An international multicenter phase 2 trial is currently accruing.

300 Longitudinal plasma proteomic profiling of non-small cell lung cancer patients undergoing immune checkpoint blockade-based therapy

Background

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment by shifting the focus from the tumor to the immune system of the host. Despite durable response to ICIs, only a small proportion of non-small lung cancer (NSCLC) patients respond to this treatment. Thus, great effort is currently focused on uncovering mechanisms of resistance and identifying predictive biomarkers for outcome.

Methods

Blood plasma was obtained from 143 NSCLC patients treated with ICI-based therapy at baseline and early on-treatment (following the first treatment), and the levels of approximately 800 proteins were determined using ELISA-based arrays. Bioinformatic analysis was performed in order to detect novel patterns of resistance to ICI-based therapy. To identify a signature that predicts clinical outcome, a machine learning algorithm was applied.

Results

Unsupervised bioinformatic analysis of the plasma proteomic profiles classified the patients into 3 clusters with distinct clinical and biological features. Patients in cluster #1 exhibited resistance to therapy, bone metastasis and high TNM (tumors, nodes and metastasis) staging; this cluster displayed high levels of proteins related to glycan and pyrimidine metabolism and cell-adhesion. Cluster #2 was enriched with responders, males, and patients with low TNM staging; this cluster displayed a strong representation of desmoglein proteins. Cluster #3 was enriched with female patients while the proteome of these patients displayed high levels of MAPK signaling related proteins. Patient clusters were largely unchanged when comparing baseline and on-treatment data, suggesting pre-existing rather than acquired resistance to therapy. A further comparison between responders and non-responders identified six significantly differentially expressed proteins comprised of both host- and tumor-related proteins, with non-responders displaying a significant enrichment of neutrophil proteins at baseline and early-on-treatment. Notably, there was no significant difference in the neutrophil count between responders and non-responders, suggesting a functional shift in neutrophils upon treatment in non-responders. Lastly, we identified a predictive signature for response comprised of two proteins and two clinical features. The performance of the predictive signature reached an area under the curve (AUC) of the receiver operating characteristics (ROC) plot of 0.8 in an independent validation subset of the cohort, indicating a high predictive power.

Conclusions

Here we performed a deep bioinformatic analysis of plasma proteome profiles of 143 NSCLC patients undergoing ICI-based therapy. Our study sheds light on underlying mechanisms of resistance to ICI-based therapy and reveals a predictive signature for response in NSCLC patients.

Ethics Approval

Data and study specimens were purchased from Indivumed and Sheba medical center, approval number 0226-13-SMC (institutional review board). Participants gave informed consent before taking part.

How to Respond to a Ransomware Attack? One Radiation Oncology Department's Response to a Cyber-Attack on Their Record and Verify System

The digitization of healthcare for patient safety and efficiency introduced third party networks into closed hospital systems increasing the probability of cyberattacks and their consequences(1). In April 2021, a major vendor of a Radiation Oncology (RO) record and verify system (RVS) suffered a ransomware attack, affecting our department and many others across the United States. This article summarizes our response to the ransomware event including workflows, team member roles, responsibilities, communications and departmental recovery. The RVS created or housed accurate patient dose records for 6 locations. The immediate response to the ransomware attack was to shut down the system including the ability to treat patients. With the utilization of the hospital EMR and pre-existing interfaces with RVS, the department was able to safely continue patient radiotherapy treatments innovatively utilizing a direct Digital Imaging and Communications in Medicine (DICOM) transfer of patient data to the linear accelerators and implementing paper charting. No patients were treated in the first 24 hours of the attack. Within 48 hours of the ransomware event, 50% of patients were treated, and within 1 week, 95% of all patients were treated using direct DICOM transfer and paper charts. The RVS was completely unavailable for 2.5 weeks and full functionality was not restored for 4.5 weeks. A phased approach was adopted for re-introduction of patient treatments back into the RVS. Human capital costs included communication, outreach, workflow creation, quality assurance and extended clinical hours. Key lessons learned were to have a back-up of essential information, employ 'dry run' emergency training, having consistent parameter requirements across different vendor hardware and software, and having a plan for the recovery effort of restoring normal operations once software is operational. The provided report presents valuable information for the development of cyber-attack preparedness for RO departments.

Utilizing Digital Health to Collect Electronic Patient-Reported Outcomes in Prostate Cancer: Single-Arm Pilot Trial

Background

Measuring patient-reported outcomes (PROs) requires an individual’s perspective on their symptoms, functional status, and quality of life. Digital health enables remote electronic PRO (ePRO) assessments as a clinical decision support tool to facilitate meaningful provider interactions and personalized treatment.

Objective

This study explored the feasibility and acceptability of collecting ePROs using validated health-related quality of life (HRQoL) questionnaires for prostate cancer.

Methods

Using Apple ResearchKit software, the Strength Through Insight app was created with content from validated HRQoL tools 26-item Expanded Prostate Cancer Index Composite (EPIC) or EPIC for Clinical Practice and 8-item Functional Assessment of Cancer Therapy Advanced Prostate Symptom Index. In a single-arm pilot study with patients receiving prostate cancer treatment at Thomas Jefferson University Hospital and affiliates, participants were recruited, and instructed to download Strength Through Insight and complete ePROs once a week over 12 weeks. A mixed methods approach, including qualitative pre- and poststudy interviews, was used to evaluate the feasibility and acceptability of Strength Through Insight for the collection and care management of cancer treatment.

Results

Thirty patients consented to the study; 1 patient failed to complete any of the questionnaires and was left out of the analysis of the intervention. Moreover, 86% (25/29) reached satisfactory questionnaire completion (defined as completion of 60% of weekly questions over 12 weeks). The lower bound of the exact one-sided 95% CI was 71%, exceeding the 70% feasibility threshold. Most participants self-identified with having a high digital literacy level (defined as the ability to use, understand, evaluate, and analyze information from multiple formats from a variety of digital sources), and only a few participants identified with having a low digital literacy level (defined as only having the ability to gather information on the Web). Interviews were thematically analyzed to reveal the following: (1) value of emotional support and wellness in cancer treatment, (2) rise of social patient advocacy in online patient communities and networks, (3) patient concerns over privacy, and (4) desire for personalized engagement tools.

Conclusions

Strength Through Insight was demonstrated as a feasible and acceptable method of data collection for ePROs. A high compliance rate confirmed the app as a reliable tool for patients with localized and advanced prostate cancer. Nearly all participants reported that using the smartphone app is easier than or equivalent to the traditional paper-and-pen approach, providing evidence of acceptability and support for the use of remote PRO monitoring. This study expands on current research involving the value of digital health, as a social and behavioral science, augmented with technology, can begin to contribute to population health management, as it shapes psychographic segmentation by demographic, socioeconomic, health condition, or behavioral factors to group patients by their distinct personalities and motivations, which influence their choices.

Trial Registration

ClinicalTrials.gov NC03197948; http://clinicaltrials.gov/ct2/show/NC03197948

The estrogen receptor α-selective agonist propyl pyrazole triol improves glucose tolerance in ob/ob mice: potential molecular mechanisms

The authors and journal apologise for an error in the above paper, which appeared in volume 199 part 2, pages 275–286. The error relates to Fig. 10, given on page 283.

The Role of Lineage Plasticity in Prostate Cancer Therapy Resistance

Lineage plasticity has emerged as an important mechanism of treatment resistance in prostate cancer. Treatment-refractory prostate cancers are increasingly associated with loss of luminal prostate markers, and in many cases induction of developmental programs, stem cell-like phenotypes, and neuroendocrine/neuronal features. Clinically, lineage plasticity may manifest as low PSA progression, resistance to androgen receptor (AR) pathway inhibitors, and sometimes small cell/neuroendocrine pathologic features observed on metastatic biopsy. This mechanism is not restricted to prostate cancer as other malignancies also demonstrate lineage plasticity during resistance to targeted therapies. At present, there is no established therapeutic approach for patients with advanced prostate cancer developing lineage plasticity or small cell neuroendocrine prostate cancer (NEPC) due to knowledge gaps in the underlying biology. Few clinical trials address questions in this space, and the outlook for patients remains poor. To move forward, urgently needed are: (i) a fundamental understanding of how lineage plasticity occurs and how it can best be defined; (ii) the temporal contribution and cooperation of emerging drivers; (iii) preclinical models that recapitulate biology of the disease and the recognized phenotypes; (iv) identification of therapeutic targets; and (v) novel trial designs dedicated to the entity as it is defined. This Perspective represents a consensus arising from the NCI Workshop on Lineage Plasticity and Androgen Receptor-Independent Prostate Cancer. We focus on the critical questions underlying lineage plasticity and AR-independent prostate cancer, outline knowledge and resource gaps, and identify strategies to facilitate future collaborative clinical translational and basic studies in this space.

Combining precision radiotherapy with molecular targeting and immunomodulatory agents: a guideline by the American Society for Radiation Oncology

The practice of radiation oncology is primarily based on precise technical delivery of highly conformal, image-guided external beam radiotherapy or brachytherapy. However, systematic research efforts are being made to facilitate individualised radiation dose prescriptions on the basis of gene-expressssion profiles that reflect the radiosensitivity of tumour and normal tissue. This advance in precision radiotherapy should complement those benefits made in precision cancer medicine that use molecularly targeted agents and immunotherapies. The personalisation of cancer therapy, predicated largely on genomic interrogation, is facilitating the selection of therapies that are directed against driver mutations, aberrant cell signalling, tumour microenvironments, and genetic susceptibilities. With the increasing technical power of radiotherapy to safely increase local tumour control for many solid tumours, it is an opportune time to rigorously explore the potential benefits of combining radiotherapy with molecular targeted agents and immunotherapies to increase cancer survival outcomes. This theme provides the basis and foundation for this American Society for Radiation Oncology guideline on combining radiotherapy with molecular targeting and immunotherapy agents.

Abstract B017: PARP-1 and E2F1 collaborate to transcriptionally regulate DNA repair factor availability

PARP-1 holds at least four major functions on chromatin: DNA damage repair, telomeric maintenance, chromatin dynamics, and transcriptional regulation—all of which are relevant in the context of cancer. Notably, PARP-1 has been found to be a key modulator of androgen receptor (AR) function and AR-dependent phenotypes, which is a driving factor in prostate cancer (PCa) biology and therapeutic management. Recent studies indicate an unanticipated prevalence of DNA repair alterations in advanced PCa and showed that PARP-1 inhibitors (PARPi) can effectively manage a subset of these tumors. Despite the functions of PARP-1 in DNA repair having been exploited as a therapeutic target for tumors with BRCA1/2 aberrations, factors beyond DNA repair alterations clearly play a role in the response to PARPi. Notably, while DNA repair defects enrich for PARPi responders, BRCA1/2 alterations do not appear to be necessary or sufficient to induce PARPi clinical response. Given the preclinical and clinical data, pursuing a deeper understanding of the molecular underpinnings of PARPi action in PCa may yield significant benefit. Human tissue microarrays were utilized to quantify PARP-1 levels and activity as a function of PCa progression. Genome-wide transcriptional profiling in response to PARPi was performed and the PARP-1-regulated transcriptome was identified. Both the PARP-1-regulated transcriptome and PARP-1 enzymatic activity were found to be elevated as a function of PCa progression. Further interrogation of the PARP-1-regulated transcriptome revealed a major impact on E2F1-regulated genes, and chromatin immunoprecipitation analyses indicated that PARP-1 functions to regulate the chromatin architecture and E2F1 occupancy at E2F1 target gene loci. Most prominent among the E2F1-regulated genes responsive to PARPi were genes associated with DNA damage repair, with a particular enrichment for genes involved in homologous recombination (HR). In sum, these data indicate that PARP-1 regulates the function of key oncogenic transcription factors (AR and E2F1) in PCa, and part of the effect of PARPi may be through downregulation of DNA repair factors.

Citation Format: Matthew J. Schiewer, Amy Mandigo, Nicolas Gordon, Fangjin Huang, Sanchaika Gaur, George Zhao, Joseph Evans, Sumin Han, Theodore Parsons, Ruth Birbe, Peter McCue, Tapio Visakorpi, Ganesh Raj, Mark Rubin, Johann de Bono, Costas Lallas, Edouard Trabulsi, Leonard Gomella, Adam Dicker, Wm. Kevin Kelly, Beatrice Knudsen, Felix Feng, Karen E. Knudsen. PARP-1 and E2F1 collaborate to transcriptionally regulate DNA repair factor availability [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B017.

Targeting Myeloid-derived Suppressor Cells and Programmed Death Ligand 1 Confers Therapeutic Advantage of Ablative Hypofractionated Radiation Therapy Compared With Conventional Fractionated Radiation Therapy

PURPOSE

Ablative hypofractionated radiation therapy (AHFRT) presents a therapeutic advantage compared with conventional fractionated radiation therapy (CFRT) for primary and oligometastatic cancers. However, the underlying mechanisms remain largely unknown. In the present study, we compared the immune alterations in response to AHFRT versus CFRT and examined the significance of immune regulations contributing to the efficacy of AHFRT.

METHODS AND MATERIALS

We established subcutaneous tumors using syngeneic lung cancer and melanoma cells in both immunocompetent and immunocompromised mice and treated them with AHFRT and CFRT under the same biologically equivalent dose.

RESULTS

Compared with CFRT, AHFRT significantly inhibited tumor growth in immunocompetent, but not immunocompromised, mice. On the cellular level, AHFRT reduced the recruitment of myeloid-derived suppressor cells (MDSCs) into tumors and decreased the expression of programmed death-ligand 1 (PD-L1) on those cells, which unlashed the cytotoxicity of CD8⁺ T cells. Through the downregulation of vascular endothelial growth factor (VEGF), AHFRT inhibited VEGF/VEGF receptor signaling, which was essential for MDSC recruitment. When combined with anti-PD-L1 antibody, AHFRT presented with greater efficacy in controlling tumor growth and improving mouse survival. By altering immune regulation, AHFRT, but not CFRT, significantly delayed the growth of secondary tumors implanted outside the irradiation field.

CONCLUSIONS

Targeting MDSC recruitment and enhancing antitumor immunity are crucial for the therapeutic efficacy of AHFRT. When combined with anti-PD-L1 immunotherapy, AHFRT was more potent for cancer treatment.

Can post-operative prostate fossa radiation be omitted in patients with high-risk features using a genomic classifier?

101

Background: At our institution, based upon the AUA/ASTRO guidelines, discussion of adjuvant radiation therapy (ART) for patients with adverse pathologic features (APF) (pT3/positive margins) occurs in a multidisciplinary setting. We had previously offered ART to approximately 50% of these patients. We describe our evaluation of Decipher genomic testing to select patients to offer observation following prostatectomy (RP). Methods: Since March 2014, patients at Thomas Jefferson University with APF and undetectable post-operative PSA underwent Decipher genomic testing. Collectively, we decided to offer observation with salvage radiation therapy (SRT) for patients with low or intermediate risk Decipher scores. The primary outcome of this analysis was biochemical progression free survival (bPFS) with failure defined as a PSA ≥0.1 ng/mL. Results: From March of 2014 through September of 2016, 47 patients met the above criteria. The median patient age was 64 and median follow up was 16 months. Median pre-treatment PSA was 6.0 ng/mL (2.94 to 22.7 ng/mL). With regard to pathologic stage: 19% had T2c, 68% had T3a, and 13% had T3b disease. Pathologic Gleason grouping was 6%, 49%, 34%, 6%, and 4% for groups 1-5, respectively. 51% of patients had positive margins, 36% had lymph-vascular space invasion, and 53% had perineural invasion. Four patients received ART and 1 patient was lost to follow up after his initial visit. Of the remaining 42 patients, 3 patients experienced biochemical failure at 8, 27, and 44 months. Conclusions: This is the first prospective report utilizing Decipher genomic testing to stratify men with undetectable PSA and adverse pathologic features into an observation cohort following RP. Despite the stringency of our definition of biochemical failure, our observed bPFS was 87% at 3 years. Historically, in an unselected population the 3 year bPFS was 90% in those receiving ART and 65% in those receiving SRT. While these initial findings are promising, longer follow up is warranted. Our findings demonstrate the utility of genomic classifiers in patient selection and provide a safe approach to reducing over treatment in the post RP setting.

Transcriptomic heterogeneity of androgen receptor activity in primary prostate cancer: Identification and characterization of a low AR-active subclass

2

Background: Significant genomic diversity exists in the androgen receptor ( AR) and its activity (AR-A) in mCRPC. In localized prostate cancer, the biologic, prognostic, and therapeutic clinical implications of AR-A heterogeneity have yet to be interrogated Methods: Genome-wide expression profiles of FFPE RP or biopsy tumor samples were evaluated from a prospective registry cohort (n = 5,239, NCT02609269) and six retrospective institutional cohorts (n = 1,170). AR-A was calculated based on expression of 9 targets of AR.. Results: Utilizing 6,409 localized prostate adenocarcinomas with full transcriptomic data, we found there was marked inter-individual transcriptomic diversity in AR and AR-A expression, and weak correlation between them (r = 0.08 to 0.36 based on cohort), in contrast to mCRPC that has a strong correlation between AR and AR-A expression (r = 0.76). Additionally, serum PSA had no correlation to intratumoral AR-A (r = 0.06). Unsupervised hierarchical clustering identified a distinct subclass of low AR-A prostate tumors, which had increased markers of immunogenicity (decreased T-regs and MDSCs, and increased CD3 effector T-cells), increased neuroendocrine marker expression ( NCAM1, ENO2, and SCG2), and decreased DNA repair pathway expression (all p < 0.001). Clinically, low AR-A tumors had more rapid development of metastatic disease in three independent cohorts, were more prone to develop resistance to hormonal therapy and develop CRPC, and were found at an increased frequency in African-American men. Interrogating in vitro drug sensitivity analyses utilizing the NCI-60 panel, low AR-A tumors appear more sensitive to platinum chemotherapy and PARP inhibition, and less sensitive to hormone therapy and taxanes. Conclusions: The diversity in AR-signaling in localized prostate cancer represents important biological heterogeneity that is both prognostic and predictive of treatment response. These findings are provocative in that low AR-A tumors may be more susceptible to immunotherapy, PARP inhibition, platinum chemotherapy, and/or radiotherapy. Patients with low AR-A tumors warrant dedicated biomarker enhanced clinical trials.

Ensuring sample quality for blood biomarker studies in clinical trials: a multicenter international study for plasma and serum sample preparation

Background

Sample quality is critical for biomarker detection in oncology, and platelet degradation and contamination in plasma have a remarkable impact on the ability to accurately quantify many blood-based biomarkers. Platelet factor 4 (PF4) can be used as an indicator to monitor sample quality. This multicenter study aimed to determine the impact of critical components of the blood sample handling process on platelet degradation/contamination and to establish an optimal method for collecting platelet-poor plasma samples.

Methods

At each of six participating centers, blood samples were drawn from 12-13 healthy volunteers. Serum and plasma samples were prepared from whole blood samples using nine different methods that have been commonly used in ongoing multicenter trials. PF4 levels in the prepared samples were measured by enzyme-linked immunosorbent assay (ELISA). Paired t-tests were used for statistical analysis.

Results

Blood samples were collected from 74 subjects enrolled in six centers. PF4 levels were significantly higher in serum samples than in plasma samples (P<0.001), in plasma samples from blood that sat at room temperature for 5 minutes (P=0.021), in plasma samples prepared at an insufficient centrifugal force (P<0.001), and in plasma samples prepared from blood that sat for longer than 4 hours on ice (P=0.001). For each method, the PF4 levels did not differ significantly among the centers or between Chinese and American subjects. The methods that resulted in normal levels of PF4 involved keeping blood samples on ice for 30 minutes to <4 hours and centrifugation at 2,500-3,000 ×g for 30 min.

Conclusions

This multicenter study evaluated multiple blood sample handling conditions for minimizing platelet degradation during plasma serum preparation and determined an optimal method for preparing platelet-poor plasma. The findings of this study can be applied in future blood biomarker studies.

A Novel Cross-Disciplinary Multi-Institute Approach to Translational Cancer Research: Lessons Learned from Pennsylvania Cancer Alliance Bioinformatics Consortium (PCABC)

Background

The Pennsylvania Cancer Alliance Bioinformatics Consortium (PCABC, http://www.pcabc.upmc.edu ) is one of the first major project-based initiatives stemming from the Pennsylvania Cancer Alliance that was funded for four years by the Department of Health of the Commonwealth of Pennsylvania. The objective of this was to initiate a prototype biorepository and bioinformatics infrastructure with a robust data warehouse by developing a statewide data model (1) for bioinformatics and a repository of serum and tissue samples; (2) a data model for biomarker data storage; and (3) a public access website for disseminating research results and bioinformatics tools. The members of the Consortium cooperate closely, exploring the opportunity for sharing clinical, genomic and other bioinformatics data on patient samples in oncology, for the purpose of developing collaborative research programs across cancer research institutions in Pennsylvania. The Consortium's intention was to establish a virtual repository of many clinical specimens residing in various centers across the state, in order to make them available for research. One of our primary goals was to facilitate the identification of cancer-specific biomarkers and encourage collaborative research efforts among the participating centers.

Methods

The PCABC has developed unique partnerships so that every region of the state can effectively contribute and participate. It includes over 80 individuals from 14 organizations, and plans to expand to partners outside the State. This has created a network of researchers, clinicians, bioinformaticians, cancer registrars, program directors, and executives from academic and community health systems, as well as external corporate partners - all working together to accomplish a common mission. The various sub-committees have developed a common IRB protocol template, common data elements for standardizing data collections for three organ sites, intellectual property/tech transfer agreements, and material transfer agreements that have been approved by each of the member institutions. This was the foundational work that has led to the development of a centralized data warehouse that has met each of the institutions’ IRB/HIPAA standards.

Results

Currently, this “virtual biorepository” has over 58,000 annotated samples from 11,467 cancer patients available for research purposes. The clinical annotation of tissue samples is either done manually over the internet or semi-automated batch modes through mapping of local data elements with PCABC common data elements. The database currently holds information on 7188 cases (associated with 9278 specimens and 46,666 annotated blocks and blood samples) of prostate cancer, 2736 cases (associated with 3796 specimens and 9336 annotated blocks and blood samples) of breast cancer and 1543 cases (including 1334 specimens and 2671 annotated blocks and blood samples) of melanoma. These numbers continue to grow, and plans to integrate new tumor sites are in progress. Furthermore, the group has also developed a central web-based tool that allows investigators to share their translational (genomics/proteomics) experiment data on research evaluating potential biomarkers via a central location on the Consortium's web site.

Conclusions

The technological achievements and the statewide informatics infrastructure that have been established by the Consortium will enable robust and efficient studies of biomarkers and their relevance to the clinical course of cancer.

Abstract 3671: Anti-PD-1 treatment may potentiate the radiation-induced lung injury

Purpose: Combination of radiation therapy and anti-PD1 immunotherapy has been investigated both in the lab and in the clinic. Pneumonitis is a rare but potentially fatal toxicity of ant-programmed death-1 (PD-1) monoclonal antibodies (mAbs). The purpose of our study is to address whether anti-PD-1 mAbs will potentiate radiation-induced lung toxicity and mortality in a murine model using Small Animal Radiation Research Platform (SARRP) for lung-targeting irradiation (IR).

Methods: Both lungs of male C57bl/6 mice were targeted for 20Gy using the SARRP. Mice were stratified into 4 treatment groups receiving IgG, anti-PD1, IR + IgG, or IR + anti-PD1. IgG or anti-PD-1 mAbs administrated via i.p. injection, with a dosage of 10mg/kg, twice per week for five doses. Acute lung injury was assessed by H&E staining and flow cytometry to measure CD4 or CD8 positive T lymphocytes. A duplicate study (n=10) was performed to determine long-term survival following lung irradiation.

Results: 30 days following lung irradiation, lung tissues exhibited abnormal alveoli, with exudates and inflammatory cells in the alveolar septa (H&E staining). The extent of these changes was more prominent in IR+anti-PD-1 group. Moreover, there were significantly (2.1 fold increase; p&lt;0.05) more CD8+ cytotoxic T lymphocytes, rather than CD4+ cells lymphocytes, in the irradiated lung tissues in the group of IR+anti-PD1 compared to that of IR+IgG. Up to 120 days post IR, 90% mice survived in the group of IR+IgG while 70% mice survived in the IR+anti-PD-1 group (p=0.657).

Conclusions: Anti-PD-1 mAbs potentiates the radiation-induced pneumonitis, likely mediated by increased CD8+ cytotoxic T lymphocytes. Anti-PD-1 mAbs may increase the radiation-related mortality although it was not statistically significance at the day 120 following IR. Care should be taken for excessive lung toxicities in ongoing clinical trials of combining thoracic RT and anti-PD1 therapy. We will collaborate with NRG to further investigate clinical lung toxicities from combining thoracic radiotherapy with Nivo in the ongoing RTOG 3505 though analyzing the collected biospecimens.

Note: This abstract was not presented at the meeting.

Citation Format: Jianxin Xue, Shisuo Du, You Lu, Adam Dicker, Bo Lu. Anti-PD-1 treatment may potentiate the radiation-induced lung injury [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3671. doi:10.1158/1538-7445.AM2017-3671

Abstract 5847: SIRT1 protects against radiation-induced lung injury via de-acetylating the Ku70 and P65

Radiation-induced lung injury (RILI) is a common and serious complication in the radiation therapy of thoracic cancer, which significantly restricts the radiation doses of tumor. The prevention and treatment of RILI have long been clinical challenges. SIRT1 is an NAD+ dependent protein deacetylase and the exact role of SIRT1 in RILI remains unclear. The aim of this study is to investigate the prevention and repairing efficacy of RILI by adenovirus-mediated SIRT1 gene overexpression in a mice model. Our studies confirmed that the protein expression and activity of SIRT1 in lung tissues were decreased in RILI mice models in a time-dependent manner, but the mRNA expression level was not obviously changed. The activity of SIRT1 was elevated by orally given resveratrol, an agonist of SIRT1. The extent of RILI could be evidently alleviated by orally given resveratrol, as assayed by histopathology, malondialdehyde (MDA) and plasma cytokines (IL-1β, TNF-α and active TGF-β1). Overexpressing SIRT1 could obviously mitigate the extent of RILI (H&E staining and CT scan), the concentration of MDA and ROS in lung, IL-1β and active TGF-β1 in plasma; as well as improve the mice survival. Moreover, SIRT1 could inhibit the radiation-induced DNA damage in vivo and in vitro, and decreased the expression of acetylated- Ku70 in the lung. In vitro Co-IP experiment showed that the expression of SIRT1 in irradiated cells was reduced and the acetylated- Ku70 was increased; over-expressing SIRT1 promoted the de-acetylation of Ku70; interference of Ku70 could reverse the effect of SIRT1 in DNA repair. Furthermore, overexpressing SIRT1 could inhibit the acetylation level of NF-κB subunit RELA (P65) in the lung; in vitro report gene experiment showed that SIRT1 suppressed the NF-κB transcriptional activity. In conclusion, our results suggest that SIRT1 could evidently mitigate the RILI, repair the irradiation-induced DNA damage and inflammation via de-acetylating the Ku70 and P65. Our study may provide new avenue for the prevention and treatment of RILI in clinic.

Note: This abstract was not presented at the meeting.

Citation Format: Jianxin Xue, Lin Zhou, Feifei Na, Lei Deng, Jie Lan, Bo Lu, Adam Dicker, You Lu. SIRT1 protects against radiation-induced lung injury via de-acetylating the Ku70 and P65 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5847. doi:10.1158/1538-7445.AM2017-5847

A phase II randomized trial of Observation versus stereotactic ablative RadiatIon for OLigometastatic prostate CancEr (ORIOLE)

Background

We describe a randomized, non-blinded Phase II interventional study to assess the safety and efficacy of stereotactic ablative radiotherapy (SABR) for hormone-sensitive oligometastatic prostate adenocarcinoma, and to describe the biology of the oligometastatic state using immunologic, cellular, molecular, and functional imaging correlates. 54 men with oligometastatic prostate adenocarcinoma will be accrued. The primary clinical endpoint will be progression at 6 months from randomization with the hypothesis that SABR to all metastases will forestall progression by disrupting the metastatic process. Secondary clinical endpoints will include local control at 6 months post-SABR, toxicity and quality of life, and androgen deprivation therapy (ADT)-free survival (ADT-FS). Further fundamental analysis of the oligometastatic state with be achieved through correlation with investigational ¹⁸F–DCFPyL PET/CT imaging and measurement of circulating tumor cells, circulating tumor DNA, and circulating T-cell receptor repertoires, facilitating an unprecedented opportunity to characterize, in isolation, the effects of SABR on the dynamics of and immunologic response to oligometastatic disease.

Methods/design

Patients will be randomized 2:1 to SABR or observation with minimization to balance assignment by primary intervention, prior hormonal therapy, and PSA doubling time. Progression after 6 months will be compared using Fisher’s exact test. Hazard ratios and Kaplan-Meier estimates of progression free survival (PFS), ADT free survival (ADT-FS), time to locoregional progression (TTLP) and time to distant progression (TTDP) will be calculated based on an intention-to-treat. Local control will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Withdrawal from the study prior to 6 months will be counted as progression. Adverse events will be summarized by type and grade. Quality of life pre- and post- SABR will be measured by Brief Pain Inventory.

Discussion

The ORIOLE trial is the first randomized, non-blinded Phase II interventional study in the North America evaluating the safety and efficacy of SABR in oligometastatic hormone-sensitive prostate cancer. Leading-edge laboratory and imaging correlates will provide unique insight into the effects of SABR on the oligometastatic state.

Trial registrations

ClinicalTrials.gov Identifier: NCT02680587.

URL of Registry: https://clinicaltrials.gov/show/NCT02680587

Date of Registration: 02/08/2016.

Date of First Participant Enrollment: 05/23/2016.

Development and validation of a novel clinical-genomic risk group classification for prostate cancer incorporating genomic and clinicopathologic risk

5000

Background: It is clinically challenging to integrate genomic classifier results that report a continuous numerical risk of recurrence into treatment decisions for prostate cancer (PCa). We aimed to develop a novel clinical-genomic risk system that can readily be incorporated into treatment guidelines for localized PCa. Methods: Four multi-center cohorts (n = 6928 men; 5937 prospective samples and 991 retrospective samples with long-term follow-up) were utilized to identify and validate our clinical-genomic risk system in radical prostatectomy (RP) samples and subsequently in pre-treatment biopsy samples. All patients’ FFPE tissue underwent microarray analysis, and the expression values for 22 prespecified biomarkers that constitute Decipher were extracted. Cumulative incidence curves were constructed to estimate metastasis risk. C-indices were calculated to compare NCCN and CAPRA score to our clinical-genomic system. Results: With a median follow-up of 8 years for men in our RP cohort, the 10-year distant metastasis rates for NCCN low, favorable-intermediate, unfavorable-intermediate, and high-risk were 7.8%, 9.4%, 40.1%, and 41.4%, respectively. Our 3-tier clinical-genomic risk groups had 10-year distant metastasis rates of 3.7%, 30.7%, and 57.7%, for low, intermediate, and high-risk, which were validated in our pre-treatment biopsy cohort with 10-year rate of distant metastasis of 0%, 30.3%, and 63.2%, respectively. C-indices for the clinical-genomic system (0.84, 95%CI 0.62-0.92) were significantly improved over NCCN (0.71, 95%CI 0.59-0.84) and CAPRA (0.71, 95%CI 0.60-0.81) score. A total of 33.4% of men would be reclassified by the clinical-genomic system, and specifically 17.1%, 41.3%, and 19.4% of men in NCCN low, intermediate and high risk groups would be reclassified by our new system. Conclusions: The use of a readily available genomic classifier in combination with clinicopathologic variables can generate a simple to use 3-tier clinical-genomic risk system that is highly prognostic for distant metastasis, is more accurate than clinical risk, and can be easily incorporated into NCCN guidelines to inform treatment decisions.

An exploratory study to investigate the immunomodulatory activity of radiation therapy in combination with pembrolizumab in patients with renal cell cancer

e16058

Background: Preclinical data suggest there are synergistic effects of radiation therapy (RT) and check point inhibitors in anticancer immunity. The primary objective of this study was to explore the immunomodulatory activity of RT alone or in combination with Pembrolizumab (pembro) in solid tumors including renal cell cancer (RCC) patients (pts). Methods: RCC pts who progressed after at least one front-line therapy were eligible. Pts were treated with either RT (8Gy x 1 or 4Gy x 5) followed by (f/b)pembro or 1 dose pembro f/b RT f/b pembro. Pre- and post RT tumor biopsy was obtained to evaluate PD-L1 expression (assay by QualTeck). Immune markers from peripheral blood before, during, and after treatment were analyzed using flow cytometry. Treatment response was measured based on modified RECIST criteria. Results: Twelve RCC patients were enrolled including 2 with non-clear cell subtype. One pt was not evaluable since pt quickly deteriorated and was taken off study. As of January 13, 2017, 2 pts are still on active treatment. Two pts had partial response (18%) and were on study for at 54 and 63 weeks. One responder was treated with 8 Gy f/b pembro while 1 was treated with 1 dose pembro f/b RT f/b pembro. Five pts had stable disease of 18 to 45 weeks and 4 pts (36%, non-responders) had progression in 9 weeks. For adverse events, 1 pt developed grade 3 pneumonitis after 10 cycles of pembro (RT to adrenal mets). Grade 3 AEs include Fatigue, Nausea, Hyperglycemia, Lymphopenia, thrombocytopenia and AST elevation (post RT for liver mets). PDL1 expression and tumor infiltrating lymphocytes presence after RT showed various patterns. Preliminary flow cytometry showed persistent higher numbers of monocytes in non-responders comparing with responders. CD4+, CD8+ and NK cells and other markers are under analyzed and the results will be presented. Conclusions: The combination of RT (8Gy or 20Gy) with pembro is feasible and tolerated, and demonstrates clinical activity. The AE profile is similar to single agent pembro. Monocytes, T and NK cell kinetics are being examined. (ClinicalTrials.gov ID: NCT02318771) Clinical trial information: NCT02318771.

Comparison of Online 6 Degree-of-Freedom Image Registration of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Intracranial Radiosurgery

PURPOSE

The study was aimed to compare online 6 degree-of-freedom image registrations of TrueBeam cone-beam computed tomography and BrainLab ExacTrac X-ray imaging systems for intracranial radiosurgery.

METHODS

Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (version 2.5), which is integrated with a BrainLab ExacTrac imaging system (version 6.1.1). The phantom study was based on a Rando head phantom and was designed to evaluate isocenter location dependence of the image registrations. Ten isocenters at various locations representing clinical treatment sites were selected in the phantom. Cone-beam computed tomography and ExacTrac X-ray images were taken when the phantom was located at each isocenter. The patient study included 34 patients. Cone-beam computed tomography and ExacTrac X-ray images were taken at each patient's treatment position. The 6 degree-of-freedom image registrations were performed on cone-beam computed tomography and ExacTrac, and residual errors calculated from cone-beam computed tomography and ExacTrac were compared.

RESULTS

In the phantom study, the average residual error differences (absolute values) between cone-beam computed tomography and ExacTrac image registrations were 0.17 ± 0.11 mm, 0.36 ± 0.20 mm, and 0.25 ± 0.11 mm in the vertical, longitudinal, and lateral directions, respectively. The average residual error differences in the rotation, roll, and pitch were 0.34° ± 0.08°, 0.13° ± 0.09°, and 0.12° ± 0.10°, respectively. In the patient study, the average residual error differences in the vertical, longitudinal, and lateral directions were 0.20 ± 0.16 mm, 0.30 ± 0.18 mm, 0.21 ± 0.18 mm, respectively. The average residual error differences in the rotation, roll, and pitch were 0.40°± 0.16°, 0.17° ± 0.13°, and 0.20° ± 0.14°, respectively. Overall, the average residual error differences were <0.4 mm in the translational directions and <0.5° in the rotational directions. ExacTrac X-ray image registration is comparable to TrueBeam cone-beam computed tomography image registration in intracranial treatments.

Genomic classifier to augment the role of pathological features in identifying optimal candidates for adjuvant radiation therapy in patients with prostate cancer: Development and internal validation of a multivariable prognostic model

142

Background: Despite documented oncological benefit, postoperative adjuvant radiotherapy (aRT) utilization in prostate cancer (PCa) patients is still limited in the US. We aimed to develop and internally validate a risk stratification tool incorporating the Decipher score, along with routinely available clinicopathologic features, to identify patients who would benefit the most from aRT. Methods: Our cohort included a total of 512 PCa patients treated with RP at one of four US academic centers between 1990-2010. All patients had ≥ pT3a disease, positive margins, and/or pathologic lymph node invasion (LNI). Multivariable Cox regression analysis (MVA) tested the relationship between available predictors (including Decipher score) and clinical recurrence (CR), which were then used to develop a novel risk stratification tool. Our study adhered to the TRIPOD guidelines for development of prognostic models. Results: Overall, 21.9% patients received aRT. Median follow-up in censored patients was 8.3 years. The 10-year CR rate was 4.9% vs. 17.4% in patients treated with aRT vs. initial observation (p < 0.001). Pathological T3b/T4 stage, Gleason score 8-10, LNI and Decipher score > 0.6 were independent predictors of CR (all p < 0.01) Cumulative number of risk factors was 0, 1, 2, and 3-4 in respectively 46.5, 28.9, 17.2, and 7.4% of patients. Adjuvant RT was associated with decreased CR rate in patients with ≥ 2 risk factors (10-year CR rate 10.1% in aRT vs. 42.1% in initial observation, p = 0.008), but not in those with < 2 risk factors (p = 0.23). Conclusions: Utilizing the novel model to indicate aRT might reduce overtreatment, decrease unnecessary side effects, and reduce risk of CR in the subset of patients (~25% of all patients with aggressive pathological disease) who really benefit from this therapy.

Individual patient level meta-analysis of the performance of the Decipher genomic classifier in high-risk men post-prostatectomy to predict development of metastatic disease

133

Background: The genomic classifier, Decipher, has been validated to predict risk of metastasis after radical prostatectomy (RP). However, the cohort size and event rate in the previous studies did not allow for a thorough investigation into performance within individual clinicopathologic or treatment subgroups. In this study, we present the first meta-analysis of the performance of the 22-marker genomic classifier in men with prostate cancer (PCa) post-RP. Methods: MEDLINE, EMBASE, and the Decipher genomic resource information database were searched for published reports of men with PCa treated by RP between 2010 and 2016 where the benefit of the Decipher genomic classifier test was assessed. The primary end point was the ability of Decipher to independently improve prognostication of regional or distant metastasis over routine clinicopathologic factors. Meta-analysis was performed with random-effects modeling, and extent of heterogeneity between studies was determined with the I2 test. Results: Five studies (975 total patients, and 855 with individual patient genomic and clinicopathologic data) were eligible for analysis. The median follow-up was 8 years. All patients had clinical high-risk disease, yet 60.9%, 22.6%, and 16.5% of patients were classified as low, intermediate, and high-risk, respectively by Decipher and had 10-year cumulative incidence rates of metastases of 5.5%, 15.0% and 26.7% (p < 0.001), respectively. Adjusting for standard clinicopathologic variables, on multivariable analysis Decipher remained a statistically significant predictor of metastasis (hazard ratio [HR] 1.30 per 0.1 unit, 95% confidence interval [CI] 1.14-1.47, p < 0.001), and the summary HR for metastasis of Decipher across the 5 studies was 1.52 (95% CI 1.39-1.67) per 0.1 unit. Conclusions: The genomic classifier test, Decipher, has the ability to independently improve prognostication of men post-RP, as well as within nearly all clinicopathologic and treatment subgroups. Strong consideration should be given to incorporating the use of genomic testing in clinical decision making and clinical trials to better individualize treatment.

An exploratory study to investigate the immunomodulatory activity of radiation therapy in combination with pembrolizumab in patients with renal cell cancer

518

Background: Preclinical data suggest there are synergistic effects of radiation therapy (RT) and check point inhibitors in anticancer immunity. The primary objective of this study was to explore the immunomodulatory activity of RT alone or in combination with Pembrolizumab (pembro) in solid tumors including renal cell cancer (RCC) patients (pts). Methods: RCC pts who progressed after at least one front-line therapy were eligible. Pts were treated with either RT (8Gy x 1 or 4Gy x 5) followed by (f/b) pembro or 1 dose pembro f/b RT f/b pembro. Pre- and post RT tumor biopsy was obtained to evaluate PD-L1 expression (assay by QualTeck). Immune markers from peripheral blood before, during, and after treatment were analyzed using flow cytometry. Treatment response was measured based on modified RECIST criteria. Results: 12 RCC patients were enrolled including 2 with non-clear cell subtype. One pt was not evaluable since pt quickly deteriorated and was taken off study. As of September 30, 2016, 5 pts were still on study with 3 pts having partial response (27.2%, responders) and were on study for at least 9.8 months. 2 responders were treated with 8 Gy f/b pembro while 1 was treated with pembro f/b RT f/b pembro. Six pts (54.5%, non-responders) had PFS between 2 – 4 m and were off study. For adverse events, 1 pt developed grade 4 pneumonitis after 10 cycles of pembro (RT to adrenal mets). Grade 3 AEs include fatigue, nausea, hyperglycemia, lymphopenia, thrombocytopenia, and AST elevation (post RT for liver mets). PDL1 expression and tumor infiltrating lymphocytes presence after RT showed various patterns. Preliminary flow cytometry showed persistent higher numbers of monocytes in non-responders compared with responders. CD4+, CD8+, and NK cells and other markers are under-analyzed and the results will be presented. Conclusions: The combination of RT (8Gy or 20Gy) with pembro is feasible and tolerated, and demonstrates clinical activity. The AE profile is similar to single agent pembro. Monocytes, T, and NK cell kinetics are being examined. Clinical trial information: NCT02318771.

Evaluating the effect of therapy duration on survival in patients with metastatic castration-resistant prostate cancer receiving radium-223

e593

Background: The use of radium-223 in patients with metastatic castration-resistant prostate cancer (mCRPC) improves overall survival (OS) and quality of life. Combination of radium-223 with second-generation anti-androgens has further improved OS; however, the optimal length of radium-223 treatment for maximal effect remains unknown. Methods: We reviewed 35 consecutive patients with mCRPC who received radium-223 from December 2012 to August 2015 at Thomas Jefferson University. Patients were divided into two groups: those who received full treatment of 6 injections (n = 18) versus those who received less than 6 injections (n = 17). Kaplan-Meier analysis of OS were tested for difference by treatment group using Log Rank test. Univariable association with survival outcomes was calculated with univariable Cox regression and Log Rank tests. Results: Mean age was 73 ± 10 years and Karnofsky performance status (KPS) ranged from 50-90 (median, 80). Median follow-up was 13.9 months. Eighteen patients were receiving concurrent second generation anti-androgens at the start of treatment. Median OS was 12 months for patients who received 6 injections and 6.48 months for patients who received less than 6 injections (p = 0.0045). The results of univariate Cox regression analysis revealed full treatment was associated with increased OS (p = 0.0013). On multivariate analysis accounting for KPS, full treatment was significantly associated with improved OS (p = 0.0028). Conclusions: In this retrospective, single-institution analysis, we demonstrated that full course completion of radium-223 was associated with improved OS in patients with mCRPC. These patients should be optimally supported during treatment to allow for therapy completion.

Capturing the patient voice in radiotherapy trials: An analysis of trends and future directions of patient-reported outcomes

216

Background: The importance of patient-reported outcomes (PROs) has been recognized and this data is increasingly being incorporated into modern radiotherapy (RT) trial design. Despite this, there is a lack of published data regarding collection and reporting of PRO data in the RT setting. We sought to systematically evaluate RT protocols to assess trends of PRO data collection and factors associated with reporting. Methods: We queried multi-institutional RT trials indexed on ClinicalTrials.gov, the Cochrane database, and MEDLINE and identified trials with full protocols available. We collected information in regards to study population, primary and secondary endpoints, quality of life measures, and PRO data. Descriptive and chi-squared analyses were employed to investigate trends and factors associated with PRO reporting. Results: 232 protocols were evaluable (1971-2014) from multiple cooperative groups. Of these, 198 were completed and 34 were in progress. Overall, only 41% of trials had protocol-specified collection of PROs. Of the 155 trials that had at least 1 published report, only 34 (22%) reported PRO data. All nine trials with PRO as a primary endpoint (9/9) had published reports with this information. Treatment era was associated with PRO collection, with 30% of trials collecting PRO data prior to 2005, 48% between 2006 and 2010, and 66% between 2011 and 2015 ( X2 [4, N = 232] = 15.79, p = 0.003). PROs were most likely to be collected in phase III trials ( X2 [4, N = 226] = 59.6, p < 0.0001). Conclusions: PROs are historically under collected and reported in cooperative group RT trials. Despite increasing PRO collection in modern trials, reporting remains suboptimal and may inaccurately inform survivorship issues. As digital literacy progresses, electronic PRO data may offer a potential avenue for improvement. Ultimately, PRO data will serve as a vital component to help define value in newly proposed payment models focused on improving quality of care while reducing cost of care.

Dosimetric validation for an automatic brain metastases planning software using single-isocenter dynamic conformal arcsDosimetric validation for an automatic brain metastases planning software using single-isocenter dynamic conformal arcs

An automatic brain‐metastases planning (ABMP) software has been installed in our institution. It is dedicated for treating multiple brain metastases with radiosurgery on linear accelerators (linacs) using a single‐setup isocenter with noncoplanar dynamic conformal arcs. This study is to validate the calculated absolute dose and dose distribution of ABMP. Three types of measurements were performed to validate the planning software: 1, dual micro ion chambers were used with an acrylic phantom to measure the absolute dose; 2, a 3D cylindrical phantom with dual diode array was used to evaluate 2D dose distribution and point dose for smaller targets; and 3, a 3D pseudo‐in vivo patient‐specific phantom filled with polymer gels was used to evaluate the accuracy of 3D dose distribution and radiation delivery. Micro chamber measurement of two targets (volumes of 1.2 cc and 0.9 cc, respectively) showed that the percentage differences of the absolute dose at both targets were less than 1%. Averaged GI passing rate of five different plans measured with the diode array phantom was above 98%, using criteria of 3% dose difference, 1 mm distance to agreement (DTA), and 10% low‐dose threshold. 3D gel phantom measurement results demonstrated a 3D displacement of nine targets of 0.7±0.4 mm (range 0.2 ~ 1.1 mm). The averaged two‐dimensional (2D) GI passing rate for several region of interests (ROI) on axial slices that encompass each one of the nine targets was above 98% (5% dose difference, 2 mm DTA, and 10% low‐dose threshold). Measured D95, the minimum dose that covers 95% of the target volume, of the nine targets was 0.7% less than the calculated D95. Three different types of dosimetric verification methods were used and proved the dose calculation of the new automatic brain metastases planning (ABMP) software was clinical acceptable. The 3D pseudo‐in vivo patient‐specific gel phantom test also served as an end‐to‐end test for validating not only the dose calculation, but the treatment delivery accuracy as well.

PACS number(s): 87.53.Lv, 87.55.km, 87.55.Qr

Effect of caloric restriction on the efficacy of radiation in both hormone-sensitive and hormone-resistant prostate cancers

16

Background: Locally advanced prostate cancers (LAPC) are aggressive, have poor prognosis, and are associated with high recurrence rates and conversion to castrate resistance. The molecular underpinnings of LAPC are being investigated to identify novel therapeutics. Animal models have shown that caloric restriction (CR) can potentially prevent the initiation of prostate cancer. We propose that CR may be used as a novel therapeutic intervention to enhance outcomes of radiation treatment by altering the molecular profile of prostate tumors. Methods: To assess the effect of CR with radiation in vivo, 6 week old male nude mice were injected with LNCaP (hormone sensitive, N = 60) or PC3 (hormone refractory, N = 60) tumor cells. Once tumors were palpable, mice were randomized to be treated with one of 4 conditions: ad libitum (AL) diet, 8Gy of radiation (RT), 30% reduction in caloric intake (CR), or CR+RT. Results: After PC3 tumor injection, compared with AL, the mice had a 22% reduction in tumor size with radiation, 77% with CR (p < 0.01) and an 80% reduction with CR+RT (p < 0.01). After LNCaP tumor injection, compared with ad libitum, the mice had a 49% reduction in tumor size with CR and a 55% reduction with CR+RT (p < 0.01). Tissue evaluation of mice treated with CR or CR+RT from both the LNCaP and PC3 models revealed decreased proliferation via Ki-67 and increased apoptosis with cleaved caspase-3 levels. Furthermore we establish significant changes of the pro-inflammatory IGF-1R pathway hypothesized to play in intricate roll in prostate cancer; down regulation of serum IGF-1R, IRS-1, PI3K, pAKT, and IGF-1:IGF-BP3. Conclusions: For the first time, we have shown that the efficacy of radiation can be increased by decreasing calories by 30% in both hormone-sensitive and hormone-refractory prostate cancer models. Future clinical trials should consider the innovative use of CR to augment standard cancer therapy as it has the potential to change the biology of tumors and enhance the opportunity for clinical benefit.

Efficacy of early and delayed radiation in a prostatectomy cohort adjusted for genomic and clinical risk

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Background: In 3 published randomized trials, adjuvant radiation therapy (ART) for prostate cancer (PCa) resulted in improved progression free survival. However, the impact on metastases and overall survival is unclear. To date, there have been no published prospective trials examining the impact of salvage radiation therapy (SRT) in this disease state. Hence, we conducted a retrospective, nonrandomized comparative study of ART, SRT, or no radiation following radical prostatectomy (RP) for men with pT3 disease or positive margins (adverse pathologic features, APF). Methods: 422 PCa men treated at 4 institutions with RP and having APF were analyzed with a primary end point of clinical metastasis. ART (n = 111), early SRT (n = 70) and delayed SRT (n = 83) were defined by PSA levels of < 0.2, 0.2 to 0.5, and ≥ 0.5 ng/mL, respectively, prior to RT initiation. Remaining 157 men who did not receive additional therapy prior to metastatic onset formed the no RT arm. Clinical-genomic risk was assessed by CAPRA-S and Decipher. Cox multivariable (MVA) model was used to evaluate the impact of treatment on outcome. Results: During study follow-up, 37 men developed metastasis with a median follow-up of 8 years. Both CAPRA-S and Decipher had independent predictive value on MVA for metastatic outcome (both p < 0.05). On MVA adjusting for clinical-genomic risk, delayed SRT and no RT had an HR of 4.31 (95%CI, 1.20-15.47) and 5.42 (95% CI, 1.59-18.44) for metastasis compared to ART. No significance difference was observed between early SRT and ART (p = 0.28). Men with low to intermediate CAPRA-S and low Decipher have a low rate of metastatic events regardless of treatment selection. In contrast, men with high CAPRA-S and Decipher benefit from ART, however the cumulative incidence of metastasis remains high. Conclusions: The decision as to the timing and need for additional local therapy following RP is nuanced and requires providers and men to balance risks of morbidity with improved oncologic outcomes. This analysis provides the most robust and accurate quantification of risk for these men. Post-RP treatment can be safely avoided for men who are low risk by clinical-genomic risk, whereas those at high risk should favor enrollment in clinical trials.

Development and validation of an ADT resistance signature to predict adjuvant hormone treatment failure

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Background: Androgen deprivation therapy (ADT) is one of the main treatment options for locally advanced and metastatic prostate cancer. Neuroendocrine prostate cancer (NEPC) is inherently less sensitive or even resistant to ADT. NEPC can be observed de novo (e.g., small cell prostate cancer) but more commonly arises after exposure to ADT. We hypothesized that a gene expression signature of NEPC when measured in primary tumor specimens (RP) of prostatic adenocarcinoma may be useful for predicting patients with innate resistance to ADT. Methods: Expression profiles of 1023 PCa patients treated with RP were obtained from the Decipher GRID database. These were split into training (n=529) and validation (n=494) sets and stratified by the receipt of adjuvant ADT (n=243) or no adjuvant ADT (n=780). A literature review of ADT resistance and neuroendocrine genes identified 1,557 genes as candidates. This set was further filtered, using logistic regression to select a 52-gene ADT resistance signature (ARS). ARS was trained using a generalized linear model with lasso regularization. Survival c-index and Kaplan Meier was used to compare survival differences between treated and untreated patients with high and low ARS scores (defined by median split). Results: In validation cohorts, the ARS was predictive of metastasis in cohorts receiving adjuvant ADT (10-year metastasis free survival c-index of 0.69 (95% CI 0.59-0.78) as compared to 0.45 (95% CI 0.29-0.61) in patients not treated with ADT). Similarly in a separate cohort of untreated patients that received no ADT until after metastatic onset, ARS was not prognostic (c-index 0.53). Among ADT treated patients, those with low ARS scores had a 10 year MFS of 87%, versus 70% in those with high ARS scores (p<0.001). In the subset of men who received ADT after metastatic onset and who developed castrate-resistant prostate cancer (CRPC, n = 41), median time to treatment failure was 1 year in patients with high ARS compared to 2 years for those with low ARS scores (p=0.07). Conclusions: A 52-gene ADT resistance signature was developed which showed significant differences in metastasis-free survival among adjuvant hormone treated but not untreated patients.

Validation of a genomic classifier for prediction of metastasis following postoperative salvage radiation therapy

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Background: Management of patients with a postoperative rising prostate-specific antigen (PSA) level is complex. Additional local treatment such as salvage radiation therapy (SRT) may be sufficient for many patients but some may require concurrent systemic therapy in order to delay or prevent metastatic disease. As PSA recurrence on its own is a poor surrogate for metastatic disease we hypothesized that the Decipher genomic classifier (GC), a validated predictor of metastasis may be able to better distinguish those patients where additional therapy is beneficial from those where SRT on its own is likely sufficient. Methods: Genomic classifier (GC) scores were calculated from 170 prostate cancer patients, who received SRT at the Veteran Affairs Medical Center Durham, Thomas Jefferson University and Mayo Clinic, between 1990 and 2010. SRT was defined as administration of RT with Pre-RT PSA levels > 0.2 ng/ml. GC and CAPRA-S scores were compared using survival c-index, competing-risks and Cox regression analysis for the prediction of metastasis. Results: Survival c-index for predicting metastasis 5 years post SRT was 0.85 (95% CI: 0.73-0.88) for GC and 0.63 (95% CI: 0.49-0.77) for CAPRA-S. The cumulative incidence of metastasis at 5 years post-SRT was 2.7%, 8.4%, and 33.1% for low, average, and high GC scores (p < 0.001) and 16.9%, 2.3% and 17.2% for low, average and high CAPRA-S scores (p = 0.113). In univariable analysis only GC, extraprostatic extension, path GS and Pre-RT PSA were significant predictors of metastasis. In multivariable analyses with clinical risk factors or the CAPRA-S risk model, GC was the only independent predictor of metastasis with a HR of 1.63 (1.22-2.18, p < 0.001) for a 10% unit increase in risk score. Conclusions: In patients treated with postoperative SRT for PSA recurrence, GC is a powerful predictor of metastasis. Patients with low Decipher have excellent prognosis with SRT and may avoid concurrent hormonal therapy. Patients with high Decipher risk are at highest risk for metastatic disease and SRT failure and may benefit from intensified systemic therapy.

Closed loop control of a robot assisted smart flexible needle for percutaneous intervention

This paper presents the experimental evaluation of a coordinated control system for a robot and robot-driven shape memory alloy (SMA) actuated smart flexible needle capable of following a curved path for percutaneous intervention. The robot driving the needle is considered the outer loop and the non-linear SMA actuated flexible needle system comprises the inner loop. The two feedback control loops are coordinated in such a way that the robot drives the needle while monitoring the needle's actual deflection against a preplanned ideal trajectory, so that the needle tip reaches the target location within an acceptable accuracy. In air and in water experimental results are presented to validate the ability of the proposed coordinated controller to track the overall desired trajectory which includes the combined trajectory of the robot driver and the needle.