Comprehensive radiotherapy for pediatric Ewing Sarcoma: Outcomes of a prospective proton study

BACKGROUND AND PURPOSE

Patients with Ewing Sarcoma (EWS) are treated with multimodality therapy which includes radiation therapy (RT) as an option for local control. We report on the efficacy after proton radiation therapy (PRT) to the primary site for localized and metastatic EWS.

MATERIALS AND METHODS

Forty-two children with EWS (33 localized, 9 metastatic) treated between 2007 and 2020 were enrolled on 2 prospective registry protocols for pediatric patients undergoing PRT. PRT was delivered by passive scatter (74 %), pencil-beam scanning (12 %) or mixed technique (14 %). Treated sites included the spine (45 %), pelvis/sacrum (26 %), skull/cranium (14 %), extraosseous (10 %), and chest wall (5 %). Median radiation dose was 54 Gy-RBE (range 39.6-55.8 Gy-RBE). Patients with metastatic disease received consolidative RT to metastatic sites (4 at the time of PRT to the primary site, 5 after completion of chemotherapy). Median follow-up time was 47 months after PRT.

RESULTS

The 4-year local control (LC), progression-free survival (PFS), and overall survival (OS) rates were 83 %, 71 %, and 86 %, respectively. All local failures (n = 6) were in-field failures. Tumor size ≥ 8 cm predicted for inferior 4-year LC (69 % vs 95 %, p = 0.04). 4-year PFS and OS rates were not statistically different in patients with localized versus metastatic disease (72 % vs 67 %, p = 0.70; 89 % vs 78 %, p = 0.38, respectively).

CONCLUSION

In conclusion, LC for pediatric patients with EWS treated with PRT was comparable to that of historical patients who received photon-RT. Tumor size ≥ 8 cm predicted increased risk of local failure. Patients with metastatic disease, including non-pulmonary only metastases, received radiation therapy to all metastatic sites and had favorable survival outcomes.

Treatment and outcomes of clear cell sarcoma of the kidney: A report from the Children's Oncology Group studies AREN0321 and AREN03B2

BACKGROUND

On the fifth National Wilms Tumor Study, treatment for clear cell sarcoma of the kidney (CCSK) included combined vincristine, doxorubicin, cyclophosphamide, and etoposide (regimen I) plus radiation therapy (RT), yielding 5-year event-free survival (EFS) rates of 100%, 88%, 73%, and 29% for patients who had with stage I, II, III, and IV disease, respectively. In the Children's Oncology Group study AREN0321 of risk-adapted therapy, RT was omitted for stage I disease if lymph nodes were sampled, and carboplatin was added for stage IV disease (regimen UH-1). Patients who had stage II/III disease received regimen I with RT.

METHODS

Four-year EFS was analyzed for patients enrolled on AREN0321 and on those enrolled on AREN03B2 who received AREN0321 stage-appropriate chemotherapy.

RESULTS

Eighty-two patients with CCSK enrolled on AREN0321, 50 enrolled on AREN03B2 only. The 4-year EFS rate was 82.7% (95% confidence interval [CI], 74.8%-91.4%) for AREN0321 and 89.6% (95% CI, 81.3%-98.7%) for AREN03B2 only (p = .28). When combining studies, the 4-year EFS rates for patients who had stage I (n = 10), II (n = 47), III (n = 65), and IV (n = 10) disease were 90% (95% CI, 73.2%-100.0%), 93.4% (95% CI, 86.4%-100.0%), 82.8% (95% CI, 74.1%-92.6%), and 58.3% (95% CI, 34%-100.0%), respectively. There were no local recurrences among seven patients with stage I disease who were treated without RT. One stage I recurrence occurred in the brain, which was the most common site of relapse overall. Among patients with local stage III tumors, neither initial procedure type, margin status, nor lymph node involvement were prognostic.

CONCLUSIONS

Patients with stage I CCSK had excellent outcomes without local recurrences when treated without RT. Patients with stage IV disease appeared to benefit from a carboplatin-containing regimen, although their outcomes remained unsatisfactory. Further research is needed to improve outcomes for patients with advanced-stage disease (ClinicalTrials.gov identifiers NCT00335556 and NCT00898365).

Everolimus in combination with vandetanib in children, adolescents, and young adults: a phase I study

BACKGROUND

Combined use of inhibitors of mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF-2) receptors is a potential strategy to overcome resistance to either class of drugs when used alone.

PATIENTS AND METHODS

We designed a phase 1 trial to test the drug combination of a multikinase VEGF receptor 2 inhibitor, vandetanib, and an mTOR inhibitor, everolimus, in a pediatric and young adult patient cohort with advanced cancers. Exceptional responders were probed for tumor mutational profile to explore possible molecular mechanisms of response.

RESULTS

Among 21 enrolled patients, clinical benefit was observed in 38% (one patient with partial response and eight patients with stable disease) with a median progression-free survival of 3.3 months. The most common treatment-related adverse event was rash (n = 13). Other treatment-related toxicities included diarrhea, fatigue, hypertension, QT prolongation, hypertriglyceridemia/hypercholesterolemia, transaminitis, thrombocytopenia, and weight loss. None of the patients experienced dose-limiting toxicities. Three exceptional responders were analyzed and were found to harbor genetic alterations including kinase insert domain receptor (KDR) Q472H mutation, EWSR1-CREB3L1, CDKN2A/B loss, and ASPL/ASPSCR1-TFE3 fusion.

CONCLUSIONS

The combination of vandetanib and everolimus showed early activity and tolerable toxicity profile in pediatric patients with advanced cancers.

Circulating microRNAs and Cytokines as Prognostic Biomarkers for Doxorubicin-Induced Cardiac Injury and for Evaluating the Effectiveness of an Exercise Intervention

PURPOSE

To define a set of biomarkers that can be used to identify patients at high risk of developing late doxorubicin (DOX)-induced cardiac morbidity with the goal of focused monitoring and early interventions.

EXPERIMENTAL DESIGN

Mice received phosphate buffered saline or DOX 2.5 mg/kg 2x/week for 2 weeks. Blood samples were obtained before and after therapy for quantification of miRNAs (6 and 24 hours), cytokines (24 hours), and troponin (24 hours, 4 and 6 weeks). Cardiac function was evaluated using echocardiography before and 24 hours after therapy. To assess the effectiveness of exercise intervention in preventing DOX-induced cardiotoxicity blood samples were collected from mice treated with DOX or DOX + exercise. Plasma samples from 13 DOX-treated patients with sarcoma were also evaluated before and 24 hours after therapy.

RESULTS

Elevations in plasma miRNA-1, miRNA-499 and IL1α, IL1β, and IL6 were seen in DOX-treated mice with decreased ejection fraction and fractional shortening 24 hours after DOX therapy. Troponin levels were not elevated until 4 weeks after therapy. In mice treated with exercise during DOX, there was no elevation in these biomarkers and no change in cardiac function. Elevations in these biomarkers were seen in 12 of 13 patients with sarcoma treated with DOX.

CONCLUSIONS

These findings define a potential set of biomarkers to identify and predict patients at risk for developing acute and late cardiovascular diseases with the goal of focused monitoring and early intervention. Further studies are needed to confirm the predictive value of these biomarkers in late cardiotoxicity.

Complete loss of TP53 and RB1 is associated with complex genome and low immune infiltrate in pleomorphic rhabdomyosarcoma

Rhabdomyosarcoma accounts for roughly 1% of adult sarcomas, with pleomorphic rhabdomyosarcoma (PRMS) as the most common subtype. Survival outcomes remain poor for patients with PRMS, and little is known about the molecular drivers of this disease. To better characterize PRMS, we performed a broad array of genomic and immunostaining analyses on 25 patient samples. In terms of gene expression and methylation, PRMS clustered more closely with other complex karyotype sarcomas than with pediatric alveolar and embryonal rhabdomyosarcoma. Immune infiltrate levels in PRMS were among the highest observed in multiple sarcoma types and contrasted with low levels in other rhabdomyosarcoma subtypes. Lower immune infiltrate was associated with complete loss of both TP53 and RB1. This comprehensive characterization of the genetic, epigenetic, and immune landscape of PRMS provides a roadmap for improved prognostications and therapeutic exploration.

Severe Hepatopathy in National Wilms Tumor Studies 3-5: Prevalence, Clinical Features, and Outcomes After Reintroduction of Chemotherapy

PURPOSE

The safety of reintroducing chemotherapy in the pediatric renal tumor setting after severe hepatopathy (SH), including sinusoidal obstruction syndrome (SOS), is uncertain. We describe the incidence, severity, outcomes, and impact on subsequent treatment for patients with SH from National Wilms Tumor Study (NWTS) protocols 3-5.

PATIENTS AND METHODS

Archived charts for patients enrolled on NWTS 3-5 who met study inclusion criteria for SH by using established hepatopathy grading scales and clinical criteria were reviewed for demographics, tumor characteristics, radio- and chemotherapy details, SH-related dose modifications, and oncologic outcomes. Genomic analysis for candidate polymorphisms associated with SH was performed in 14 patients.

RESULTS

Seventy-one of 8,862 patients (0.8%) met study inclusion criteria. The median time from therapy initiation to SH was 51 days (range, 2-293 days). Sixty percent received radiotherapy, and 56% had right-sided tumors. Grade 1-4 thrombocytopenia was noted in 70% at initial occurrence of SH (median 22,000/microliter). Among 69 of 71 children with SH occurring before the end of therapy (EOT) and post-SH treatment information available, chemotherapy was delayed posthepatopathy for 65% (69% of these at a reduced dose), continued without delay for 20% (57% of these at reduced dose), and stopped completely for 15% (4 of 10 of whom died of SH). Overall, 42% of patients with dose reductions achieved full dose by EOT. The five-year post-SH event-free survival for patients who continued therapy was 89% (95% CI, 81 to 98), with no significant differences by whether delay or dose reduction occurred. We identified no SH-associated pharmacogenomic polymorphism.

CONCLUSION

The incidence of SH on NWTS 3-5 was low; many had associated severe thrombocytopenia. Careful reintroduction of chemotherapy appeared to be feasible for the majority of patients who developed severe chemotherapy- and/or radiotherapy-induced liver toxicity.

Automated Capture and Analysis of Circulating Tumor Cells in Pediatric, Adolescent and Young Adult Patients with Central Nervous System Tumors

Tumors of the central nervous system (CNS) are the most common and lethal childhood malignancy. Detection of residual disease and longitudinal monitoring of treatment response in patients are challenging and rely on serial imaging. This current standard of care fails to detect microscopic disease or provide molecular characteristics of residual tumors. As such, there is dire need for minimally invasive liquid biopsy techniques. We have previously shown the high specificity of using cell surface vimentin (CSV) to identify circulating tumor cells (CTCs) from patients bearing various types of cancers. Here, we describe the first report of CTCs captured from peripheral blood samples in 58 pediatric CNS tumor patients. In this study, we used a CSV-coated cell capture chip, the Abnova CytoQuest automated CTC isolation system, to boost the CTC capture from pediatric patients with CNS tumors. We successfully isolated CTCs in six glioma patients using immunostaining of histone H3 lysine27-to-methionine (H3K27M) mutations which are highly expressed by this tumor. We show that CSV is a viable marker for CNS CTC isolation and that this is a feasible method for detecting microscopic disease. Larger-scale studies focusing on CTCs in pediatric CNS tumors to explore their diagnostic and prognostic value are warranted.

Dissociation protocols used for sarcoma tissues bias the transcriptome observed in single-cell and single-nucleus RNA sequencing

BACKGROUND

Single-cell RNA-seq has emerged as an innovative technology used to study complex tissues and characterize cell types, states, and lineages at a single-cell level. Classification of bulk tumors by their individual cellular constituents has also created new opportunities to generate single-cell atlases for many organs, cancers, and developmental models. Despite the tremendous promise of this technology, recent evidence studying epithelial tissues and diverse carcinomas suggests the methods used for tissue processing, cell disaggregation, and preservation can significantly bias gene expression and alter the observed cell types. To determine whether sarcomas - tumors of mesenchymal origin - are subject to the same technical artifacts, we profiled patient-derived tumor explants (PDXs) propagated from three aggressive subtypes: osteosarcoma (OS), Ewing sarcoma (ES), desmoplastic small round cell tumor (DSRCT). Given the rarity of these sarcoma subtypes, we explored whether single-nuclei RNA-seq from more widely available archival frozen specimens could accurately be identified by gene expression signatures linked to tissue phenotype or pathognomonic fusion proteins.

RESULTS

We systematically assessed dissociation methods across different sarcoma subtypes. We compared gene expression from single-cell and single-nucleus RNA-sequencing of 125,831 whole-cells and nuclei from ES, DSRCT, and OS PDXs. We detected warm dissociation artifacts in single-cell samples and gene length bias in single-nucleus samples. Classic sarcoma gene signatures were observed regardless of the dissociation method. In addition, we showed that dissociation method biases could be computationally corrected.

CONCLUSIONS

We highlighted transcriptional biases, including warm dissociation and gene-length biases, introduced by the dissociation method for various sarcoma subtypes. This work is the first to characterize how the dissociation methods used for sc/snRNA-seq may affect the interpretation of the molecular features in sarcoma PDXs.

Tumor biology, biomarkers, and liquid biopsy in pediatric renal tumors

The expansion of knowledge regarding driver mutations for Wilms tumor (WT) and malignant rhabdoid tumor of the kidney (MRT) and various translocations for other pediatric renal tumors opens up new possibilities for diagnosis and treatment. In addition, there are growing data surrounding prognostic factors that can be used to stratify WT treatment to improve outcomes. Here, we review the molecular landscape of WT and other pediatric renal tumors as well as WT prognostic factors. We also review incorporation of circulating tumor DNA/liquid biopsies to leverage this molecular landscape, with potential use in the future for distinguishing renal tumors at the time of diagnosis and elucidating intratumor heterogeneity, which is not well evaluated with standard biopsies. Incorporation of liquid biopsies will require longitudinal collection of multiple biospecimens. Further preclinical research, identification and validation of biomarkers, molecular studies, and data sharing among investigators are crucial to inform therapeutic strategies that improve patient outcomes.

Durvalumab plus tremelimumab in advanced or metastatic soft tissue and bone sarcomas: a single-centre phase 2 trial

BACKGROUND

Few standard treatment options are available for patients with metastatic sarcomas. We did this trial to evaluate the efficacy, safety, and changes in the tumour microenvironment for durvalumab, an anti-PD-L1 drug, and tremelimumab, an anti-CTLA-4 drug, across multiple sarcoma subtypes.

METHODS

In this single-centre phase 2 trial, done at The University of Texas MD Anderson Cancer Center (Houston, TX USA), patients aged 18 years or older with advanced or metastatic sarcoma with an Eastern Cooperative Oncology Group performance status of 0 or 1 who had received at least one previous line of systemic therapy were enrolled in disease subtype-specific groups (liposarcoma, leiomyosarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma, synovial sarcoma, osteosarcoma, alveolar soft-part sarcoma, chordoma, and other sarcomas). Patients received 1500 mg intravenous durvalumab and 75 mg intravenous tremelimumab for four cycles, followed by durvalumab alone every 4 weeks for up to 12 months. The primary endpoint was progression-free survival at 12 weeks in the intention-to-treat population (all patients who received at least one dose of treatment). Safety was also analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02815995, and is completed.

FINDINGS

Between Aug 17, 2016, and April 9, 2018, 62 patients were enrolled, of whom 57 (92%) received treatment and were included in the intention-to-treat population. With a median follow-up of 37·2 months (IQR 1·8-10·1), progression-free survival at 12 weeks was 49% (95% CI 36-61). 21 grade 3-4 treatment-related adverse events were reported, the most common of which were increased lipase (four [7%] of 57 patients), colitis (three [5%] patients), and pneumonitis (three [5%] patients). Nine (16%) patients had a treatment related serious adverse event. One patient had grade 5 pneumonitis and colitis.

INTERPRETATION

The combination of durvalumab and tremelimumab is an active treatment regimen for advanced or metastatic sarcoma and merits evaluation in specific subsets in future trials.

FUNDING

AstraZeneca.

The androgen receptor is a therapeutic target in desmoplastic small round cell sarcoma

Desmoplastic small round cell tumor (DSRCT) is an aggressive, usually incurable sarcoma subtype that predominantly occurs in post-pubertal young males. Recent evidence suggests that the androgen receptor (AR) can promote tumor progression in DSRCTs. However, the mechanism of AR-induced oncogenic stimulation remains undetermined. Herein, we demonstrate that enzalutamide and AR-directed antisense oligonucleotides (AR-ASO) block 5α-dihydrotestosterone (DHT)-induced DSRCT cell proliferation and reduce xenograft tumor burden. Gene expression analysis and chromatin immunoprecipitation sequencing (ChIP-seq) were performed to elucidate how AR signaling regulates cellular epigenetic programs. Remarkably, ChIP-seq revealed novel DSRCT-specific AR DNA binding sites adjacent to key oncogenic regulators, including WT1 (the C-terminal partner of the pathognomonic fusion protein) and FOXF1. Additionally, AR occupied enhancer sites that regulate the Wnt pathway, neural differentiation, and embryonic organ development, implicating AR in dysfunctional cell lineage commitment. Our findings have direct clinical implications given the widespread availability of FDA-approved androgen-targeted agents used for prostate cancer.

Androgen receptor can promote tumour progression in desmoplastic small round cell tumour (DSRCT), an aggressive paediatric malignancy that predominantly affects young males. Here, the authors show that DSRCT is an AR-driven malignancy and sensitive to androgen deprivation therapy

White paper: Onco-fertility in pediatric patients with Wilms tumor

The survival of childhood Wilms tumor is currently around 90%, with many survivors reaching reproductive age. Chemotherapy and radiotherapy are established risk factors for gonadal damage and are used in both COG and SIOP Wilms tumor treatment protocols. The risk of infertility in Wilms tumor patients is low but increases with intensification of treatment including the use of alkylating agents, whole abdominal radiation or radiotherapy to the pelvis. Both COG and SIOP protocols aim to limit the use of gonadotoxic treatment, but unfortunately this cannot be avoided in all patients. Infertility is considered one of the most important late effects of childhood cancer treatment by patients and their families. Thus, timely discussion of gonadal damage risk and fertility preservation options is important. Additionally, irrespective of the choice for preservation, consultation with a fertility preservation (FP) team is associated with decreased patient and family regret and better quality of life. Current guidelines recommend early discussion of the impact of therapy on potential fertility. Since most patients with Wilms tumors are prepubertal, potential FP methods for this group are still considered experimental. There are no proven methods for FP for prepubertal males (testicular biopsy for cryopreservation is experimental), and there is just a single option for prepubertal females (ovarian tissue cryopreservation), posing both technical and ethical challenges. Identification of genetic markers of susceptibility to gonadotoxic therapy may help to stratify patient risk of gonadal damage and identify patients most likely to benefit from FP methods.

Impact of the First Generation of Children's Oncology Group Clinical Trials on Clinical Practice for Wilms Tumor

Refinements in surgery, radiation therapy, and chemotherapy since the mid-20th century have resulted in a survival rate exceeding 90% for patients with Wilms tumor (WT). Although this figure is remarkable, a significant proportion of patients continue to have event-free survival (EFS) estimates of <75%, and nearly 25% of survivors experience severe chronic medical conditions. The first-generation Children's Oncology Group (COG) renal tumor trials (AREN '0'), which opened to enrollment in 2006, focused on augmenting treatment regimens for WT subgroups with predicted EFS <75% to 80%, including those with the adverse prognostic marker of combined loss of heterozygosity (LOH) at chromosomes 1p/16q, pulmonary metastasis with incomplete lung nodule response after 6 weeks of chemotherapy, bilateral disease, and anaplastic histology. Conversely, therapy was reduced for patient subgroups with good outcomes and potential for long-term toxicity, such as those with lung metastasis with complete lung nodule response after 6 weeks of chemotherapy. This article summarizes the key findings of the first-generation COG renal tumor studies and their implications for clinical practice.

Cell-surface vimentin positive circulating tumor cells as a diagnostic and prognostic indicator in pediatric sarcoma patients

e15022

Background: Despite advances in care, the 5 year overall survival for patients with relapsed and or metastatic sarcoma remains as low as < 35%. Currently, there are no biomarkers available to assess disease status in patients with sarcomas and as such, disease surveillance remains only reliant on serial imaging which increases the risk of secondary malignancies and heightens patient anxiety. Methods: Here, we enumerated the cell surface vimentin (CSV+) CTCs in the blood of 92 sarcoma pediatric and adolescent and young adult (AYA) patients. Results: We discovered the CSV+CTC could serve as a possible biomarker of disease with sensitivity of 85.3% and specificity of 75%. Significantly, patients who were deemed to be CSV+ CTC positive were found to have a worse overall survival compared to those who were CSV+ CTC negative (773 days vs 2622 days). Addition of readily available genetic analyses improved the sensitivity in both diagnostic and prognostic tests. Conclusions: Our findings indicate that CSV+ CTCs have both diagnostic and prognostic value and can possibly serve as a measure of disease burden.

Identification and characterization of de novo TP53 mutation carriers in Li-Fraumeni syndrome families: A single institution experience

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Background: Li-Fraumeni syndrome (LFS) is an inherited cancer syndrome mainly caused by a deleterious mutation in TP53. An estimated 48% of LFS patients present due to a deleterious de novo mutation (DNM) in TP53. The knowledge of DNM status, DNM or familial mutation (FM), of an LFS patient requires genetic testing of both parents which is often inaccessible, making de novo LFS patients an understudied population. Famdenovo.TP53 is a Mendelian Risk prediction model used to predict DNM status of TP53 mutation carriers based on the cancer-family history and several input genetic parameters, including disease-gene penetrance. The good predictive performance of Famdenovo.TP53 was demonstrated using data collected from four historical US cohorts. We hypothesize that by incorporating penetrance estimates that are specific for different types of cancers diagnosed in family members, we can develop a model with further improved calibration, accuracy and prediction. Methods: We present Famdenovo.CS, which uses cancer-specific penetrance estimates that were derived previously using a Bayesian semi-parametric competing risk model, to calculate the DNM probability. We use our model to analyze 101 families recently collected from the Clinical Cancer Genetic program at MD Anderson Cancer Center (CCG-TP53) that includes 20 families with known DNM status and 81 families with unknown DNM status. We used the concordance index (AUC), observed:expected ratios (OE) and Brier score (BS) to measure our model’s discrimination, calibration and accuracy, respectively. We estimate the proportion of probands that present a DNM and compare DNM to FM carriers in several areas including: cancer types diagnosed, age at diagnosis, number of primary cancers diagnosed, sex, amino acid change caused by mutation in TP53. Results: Famdenovo.CS showed equally good discrimination and calibration performance to Famdenovo.TP53, while improving the overall accuracy, demonstrated by a decrease in the Brier score of -0.09 (95% CI: [-0.02, -0.19]). Of the 101 probands in the CCG-TP53 cohort, we predict 39 to be DNMs and 62 to be FMs. The cancer types and ages of diagnosis observed in FMs and DNMs are similarly distributed. Conclusions: Famdenovo.CS shows improved model accuracy in the CCG cohort. DNMs in TP53 are a prevalent cause of LFS and we did not find differences in the clinical characteristics of DNM and FM carriers. Our model allows for a systematic identification and characterization of TP53 DNM carriers.

TK216 for relapsed/refractory Ewing sarcoma: Interim phase 1/2 results

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Background: Ewing Sarcoma (ES) is a rare cancer of the young with very few treatment options in the relapsed/refractory (R/R) setting. Fusions of the EWS gene and one of five different ETS transcription factors are dominant drivers of ES. TK216 was designed to bind ETS proteins directly, disrupt protein-protein interactions, and inhibit transcription factor function. TK216 plus vincristine (VCR) exerted synergistic activity in non-clinical models . Here, we report updated interim results of the Phase 1/2 trial of TK216 ± vincristine in R/R ES. Methods: TK216 was administered by continuous IV infusion to adult and pediatric patients (pts) with R/R ES using a 3+3 design. Dosing duration of 7 days was later extended to 10 and 14 days. Dose limiting toxicity was evaluated during Cycle 1. VCR could be added after Cycle 2. The MTD for the 14-day infusion was 200 mg/m2/d, which was selected as the recommended Phase 2 dose (RP2D) for the Expansion cohort, with VCR started in Cycle 1. Results: Thirty-two R/R pts in 9 dose and schedule escalation cohorts, and 31 pts in the Phase 2 Expansion cohort were enrolled. Thirty-five pts were treated at the RP2D. Mean age was 30.6 years and 61% were males. Median prior treatment regimens for recurrent/metastatic ES were 3 (range 0-13). Median time from initial diagnosis of ES to study start was 3.5 years (range 0.3-18.1). Prior procedures included surgery (84%) and radiation (81%). At study entry, all pts had metastases with sites being bone only (13%), pleuropulmonary only (39%), and other metastatic (47%). As of the 20JAN2021 safety cutoff, the most common AEs observed in 62 treated pts, regardless of causality, included anemia (n = 34), neutropenia (n = 30) and fatigue (n = 25). Myelosuppression observed was transient, reversible, and responsive to growth factors. No deaths were attributed to TK216. As of the 06FEB2021 efficacy cut-off, 28/35 pts treated at the RP2D were evaluable for efficacy: Complete response (CR) 7.1%, stable disease (SD) 39.3%, progressive disease (PD) 53.6%, for an overall clinical benefit (CR+PR+SD) rate of 46.4%. SD median duration was 113 days (range 62-213). Three tumor responses were notable. One pt had regression of the target lesion after 2 cycles of TK216 alone, then after 6 cycles of TK216 + VCR therapy a residual non-target lesion was removed, for a surgical CR, without PD at 24 months on study. A second pt had a CR after 6 cycles of combination therapy, without PD at 18 months on study. After 4 cycles of TK216 + VCR therapy, a third pt had a PR of the target lesion, is receiving local therapy for PD of a non-target lesion and remains on study. Pts treated with the RP2D had a longer PFS than those in the dose escalation cohorts. Conclusions: TK216 plus VCR was well tolerated and showed encouraging early evidence of anti-tumor activity in this heavily pre-treated/ high tumor burden ES pt population. Clinical trial information: NCT02657005.

A Phase I Trial of the MET/ALK/ROS1 Inhibitor Crizotinib Combined with the VEGF Inhibitor Pazopanib in Patients with Advanced Solid Malignancies

BACKGROUND

Crizotinib inhibits ALK, MET and ROS1 tyrosine kinases but the development of resistance to monotherapy is an issue. The anti-angiogenic properties of pazopanib could overcome crizotinib drug resistance. Additionally, the anti-angiogenic properties of crizotinib could augment the clinical efficacy of pazopanib.

METHODS

We evaluated the safety and responses in patients with advanced solid tumors treated with crizotinib and pazopanib.

RESULTS

Eighty-two patients (median age 53 years, range 18-78 years) were enrolled. The median number of prior systemic therapies was 3 (range, 0-8). We were able to dose escalate to dose level 8 (crizotinib 250 mg twice daily and pazopanib 800 mg daily) with no MTD identified. Grade 3 or 4 toxicities were seen in 32% of patients with the highest prevalence being fatigue (n=9, 11%), diarrhea (n=6, 7%), vomiting (n=3, 4%), anemia (n=2, 2%) and ALT increased (n=2, 2%). Of the 82 patients, 61 (74%) had measurable disease by RECISTv1.1 and reached first restaging (6 weeks). Partial response (PR) was observed in 6/61 (10%) patients, and stable disease (SD) lasting ≥6 months was observed in 10/61 patients (16%) (total = 16/61 (26%) of patients with SD ≥6 months/PR).

CONCLUSION

Dose level 6 (crizotinib 200 mg twice daily and pazopanib 600 mg daily) was the most tolerable dosing of the combination and can be used in future studies. We also observed moderate clinical activity in patients with advanced solid tumors that had received numerous prior therapies.

Metabolic compensation activates pro-survival mTORC1 signaling upon 3-phosphoglycerate dehydrogenase inhibition in osteosarcoma

Osteosarcoma is the most common pediatric and adult primary malignant bone cancer. Curative regimens target the folate pathway, downstream of serine metabolism, with high-dose methotrexate. Here, the rate-limiting enzyme in the biosynthesis of serine from glucose, 3-phosphoglycerate dehydrogenase (PHGDH), is examined, and an inverse correlation between PHGDH expression and relapse-free and overall survival in osteosarcoma patients is found. PHGDH inhibition in osteosarcoma cell lines attenuated cellular proliferation without causing cell death, prompting a robust metabolic analysis to characterize pro-survival compensation. Using metabolomic and lipidomic profiling, cellular response to PHGDH inhibition is identified as accumulation of unsaturated lipids, branched chain amino acids, and methionine cycle intermediates, leading to activation of pro-survival mammalian target of rapamycin complex 1 (mTORC1) signaling. Increased mTORC1 activation sensitizes cells to mTORC1 pathway inhibition, resulting in significant, synergistic cell death in vitro and in vivo. Identifying a therapeutic combination for PHGDH-high cancers offers preclinical justification for a dual metabolism-based combination therapy for osteosarcoma.

Primary Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Kidney: The MD Anderson Cancer Center Experience

Limited information exists on the clinical behavior of the Ewing sarcoma family of tumors (ESFT) of the kidney. We reviewed the records of 30 patients (aged 8-69 years) with ESFT of the kidney seen at our institution between 1990 and 2013. We analyzed the event-free survival (EFS) and overall survival (OS) for associations with patient demographics, disease group, tumor size, tumor thrombus, and treatment. Six patients (20%) had tumors confined to the kidney (Group I), seven (23.3%) had local tumor extension beyond the kidney (Group II), and 17 (56.7%) had distant metastasis at diagnosis (Group III). Twenty-five (83.3%) patients underwent radical (19 upfront, five delayed) or partial (one upfront) nephrectomy, 25 (83.3%) chemotherapy and four (13.3%) radiotherapy. The 4-year EFS and OS were 43% (95% CI, 26-61%) and 63% (95% CI, 46-81%), respectively. EFS and OS were significantly associated with disease group and chemotherapy (p < 0.039). The presence of tumor thrombus in renal vein and/or inferior vena cava was associated with worse EFS (p = 0.053). Patients with disease confined to the kidney treated with nephrectomy and adjuvant chemotherapy have favorable outcomes. Local tumor extension beyond the kidney, tumor thrombus, and distant metastasis are unfavorable factors that warrant intensification or novel approaches of therapy.

A prospective study of pediatric and adolescent renal cell carcinoma: A report from the Children's Oncology Group AREN0321 study

BACKGROUND

To the authors' knowledge, AREN0321 is the first prospective clinical study of pediatric and adolescent renal cell carcinoma (RCC). Goals of the study included establishing epidemiological, treatment, and outcome data and confirming that patients with completely resected pediatric RCC, including lymph node-positive disease (N1), have a favorable prognosis without adjuvant therapy.

METHODS

From 2006 to 2012, patients aged <30 years with centrally reviewed pathology of RCC were enrolled prospectively.

RESULTS

A total of 68 patients were enrolled (39 of whom were male; median age of 13 years [range, 0.17-22.1 years]). Stage was classified according to the American Joint Committee on Cancer TNM stage seventh edition as stage I in 26 patients, stage II in 7 patients, stage III in 26 patients, and stage IV in 8 patients, and was not available in 1 patient. Sixty patients underwent resection of all known sites of disease, including 2 patients with stage IV disease. Surgery included radical nephrectomy (53 patients [81.5%]), partial nephrectomy (12 patients [18.5%]), and unknown (3 patients [4.4%]). Histology was TFE-associated RCC (translocation-type RCC; tRCC) in 40 patients, RCC not otherwise specified and/or other in 13 patients, papillary RCC in 9 patients, and renal medullary carcinoma (RMC) in 6 patients. Lymph node status was N0 in 21 patients, N1 in 21 patients (tRCC in 15 patients, RMC in 3 patients, papillary RCC in 2 patients, and not otherwise specified and/or other in 1 patient), and Nx in 26 patients. The 4-year event-free survival and overall survival rates were 80.2% (95% CI, 69.6%-90.9%) and 84.8% (95% CI, 75.2%-94.5%), respectively, overall and 87.5% (95% CI, 68.3%-100%) and 87.1% (95% CI, 67.6%-100%), respectively, for the 16 patients with N1M0 disease. Among patients presenting with metastases, 2 of 8 patients (2 of 5 patients with RMC) were alive (1 with disease) at the time of last follow-up, including 1 patient who was lost to follow-up (succinate dehydrogenase deficiency). The predominant RCC subtypes associated with mortality were tRCC and RMC.

CONCLUSIONS

Favorable short-term outcomes can be achieved without adjuvant therapy in children and adolescents with completely resected RCC, independent of lymph node status. A prospective study of patients with tRCC and RMC with M1 or recurrent disease is needed to optimize treatment.

IGF-1R/mTOR Targeted Therapy for Ewing Sarcoma: A Meta-Analysis of Five IGF-1R-Related Trials Matched to Proteomic and Radiologic Predictive Biomarkers

Background : Ten to fourteen percent of Ewing sarcoma (ES) study participants treated nationwide with IGF-1 receptor (IGF-1R)-targeted antibodies achieved tumor regression. Despite this success, low response rates and short response durations (approximately 7-weeks) have slowed the development of this therapy. Methods: We performed a meta-analysis of five phase-1b/2 ES-oriented trials that evaluated the anticancer activity of IGF-1R antibodies +/− mTOR inhibitors (mTORi). Our meta-analysis provided a head-to-head comparison of the clinical benefits of IGF-1R antibodies vs. the IGF-1R/mTOR-targeted combination. Available pretreatment clinical samples were semi-quantitatively scored using immunohistochemistry to detect proteins in the IGF-1R/PI3K/AKT/mTOR pathway linked to clinical response. Early PET/CT imaging, obtained within the first 2 weeks (median 10 days), were examined to determine if reduced FDG avidity was predictive of progression-free survival (PFS). Results: Among 56 ES patients treated at MD Anderson Cancer Center (MDACC) with IGF-1R antibodies, our analysis revealed a significant ~two-fold improvement in PFS that favored a combination of IGF-1R/mTORi therapy (1.6 vs. 3.3-months, p = 0.042). Low pIGF-1R in the pretreatment specimens was associated with treatment response. Reduced total-lesion glycolysis more accurately predicted the IGF-1R response than other previously reported radiological biomarkers. Conclusion: Synergistic drug combinations, and newly identified proteomic or radiological biomarkers of IGF-1R response, may be incorporated into future IGF-1R-related trials to improve the response rate in ES patients.

A phase I trial of aerosol gemcitabine for the treatment of patients with solid tumors and lung metastases

TPS3645

Background: Pre-clinical studies of aerosol gemcitabine (GCB) in mice and dogs with osteosarcoma (OS) lung metastases demonstrated therapeutic efficacy. Aerosol GCB administered once weekly proved to be safe in adults with lung cancer. Direct delivery of GCB to the lungs via inhalation may offer higher drug concentration in the tumor with fewer side effects. We initiated a Phase I study to evaluate the feasibility and safety of aerosol GCB treatment in patients >12 years with solid tumors and lung metastases (2015-0720- NCT03093909). Methods: Eligibility criteria: 1) Diagnosis of solid tumor with lung metastases, 2) willing to comply with protocol therapy, 3) adequate organ function, 4) patient age > 12 and < 50 years, 5) good performance status, 6) resolution of all acute toxic effects of any prior anti-cancer therapy, and 7) no radiotherapy within 2 weeks. Patients who previously received systemic GCB are eligible. Objectives: To determine the maximum tolerated dose (MTD) and toxicities of aerosol GCB, to evaluate for drug spillover into the circulation, and to preliminarily assess the anti-tumor activity. Correlative studies include effect of aerosol GCB on immune cell infiltration in the lung, autophagy, apoptosis, heat shock protein 27, evidence of DNA strand breaks (gH2AX) and expression of human equilibrative nucleoside transporter-1.Aerosol GCB is administered via a breath-induced nebulizer twice a week in 28-day cycles. A maximum of 6 dose levels will be studied; the starting dose is 0.75 mg/kg twice weekly. If no progressive disease or unacceptable treatment-related toxicity, patients may continue for 12 cycles. The study uses the accelerated titration method for the first 2 dose levels then the 3+3 design for the remaining dose levels. After determining the MTD, we will evaluate the defined MTD in an expansion cohort of 14 patients with relapsed OS. Symptoms, pulse oximetry, and pulmonary function are assessed prior to each nebulized dose using remote spirometry that allows raw numbers and flow-volume curves to be uploaded and transmitted via bluetooth to an android tablet provided to patients. Data is transmitted to a web portal and captured in a HIPAA-compliant web-based database (REDCap) that is accessible to the research team. Results: To date, the study enrolled 4 patients and accrual is ongoing at dose level 3. Conclusions: This study will provide information on the feasibility and safety of aerosol GCB. If proven to be feasible and safe, it can potentially offer a novel approach to treat metastatic OS to the lungs while minimizing systemic toxicity. Clinical trial information: NCT03093909 .

A phase II multi-arm study of durvalumab and tremelimumab for advanced or metastatic sarcomas

11509

Background: The combination of durvalumab (D), (anti- PD-L1) and tremelimumab (T), (anti-CTLA-4), was evaluated to determine activity in specific sarcoma subtypes (NCT02815995). We report final results of the clinical efficacy, safety and correlatives. Methods: Pts ≥12 yrs, with advanced/metastatic sarcoma, were enrolled based on subtype: LPS, LMS, angiosarcoma (AS), UPS, synovial sarcoma, osteosarcoma, ASPS, chordoma, and other sarcomas. Pts received D 1500mg and T 75mg every 4 wks for 4 cycles followed by D alone every 4 wks for up to 12 months (mo) unless the patients experienced unacceptable toxicity or disease progression. Re-treatment was allowed if progression occurred after stopping therapy within the next 12 mo. The primary end-point was PFS at 12 wks (RECIST). Secondary objectives included safety, response rates (irRC and RECIST) and survival. Biopsies were collected at baseline and at 6 wks for flow, PD-L1, multiplex IHC staining and sequencing. Results: Baseline characteristics of the 57 pts who received treatment are listed in the Table. Median OS for all pts was 20.8 mo (95% CI: 11.7, NR), the 12-mo survival was 63% (95% CI: 52%, 78%) and the 24-mo survival was 45% (95%CI: 33%, 61%). The mPFS for all pts was 4.5 mo (95% CI: 2.8, 6.9). The PFS at 12 wks for all pts was 51% (95%CI: 37%, 63%), PFS at 12 mo was 28% (95% CI: 18%, 43%), and PFS at 24 mo was 25% (95% CI: 16%, 41%). The 12 wk PFS was lowest for the LPS cohort (6 pts) at 16% (95% CI: 1%, 52%), and highest for the ASPS cohort (10 pts) at 90% (95% CI: 47%, 99%). PRs by irRC were observed in ASPS (5/10), chordoma, (1/5), UPS (1/5), and cutaneous AS (1/1), and 14 pts completed 12 mo of therapy. 14 pts (24.6%) experienced grade ≥3 related AEs (colitis, nausea, cardiac dysfunction, thyroiditis, pneumonitis, hepatitis, myositis, anemia and fatigue). Clinical benefit correlated with tumors with an inflamed phenotype; based on higher than median density of 3 major categories of tumor infiltrating lymphocytes (TIL): CD3+, CD3+CD8+, CD3+CD8+GZB+, seen in the 36 paired biopsies. Conclusions: In addition to histology (ASPS, cutaneous AS, UPS, chordoma), a higher TIL immune score can help predict clinical benefit. Clinical trial information: NCT02815995 . [Table: see text]

Activity of Vincristine and Irinotecan in Diffuse Anaplastic Wilms Tumor and Therapy Outcomes of Stage II to IV Disease: Results of the Children's Oncology Group AREN0321 Study

PURPOSE

AREN0321 evaluated the activity of vincristine and irinotecan (VI) in patients with newly diagnosed diffuse anaplastic Wilms tumor (DAWT) and whether a regimen containing carboplatin (regimen UH1) in addition to regimen I agents used in the National Wilms Tumor Study 5 (NWTS-5; vincristine, doxorubicin, cyclophosphamide, and etoposide plus radiotherapy) would improve patient outcomes.

PATIENTS AND METHODS

Patients with stage II to IV DAWT without measurable disease received regimen UH1. Patients with stage IV measurable disease were eligible to receive VI (vincristine, 1.5 mg/m² per day intravenously on days 1 and 8; irinotecan, 20 mg/m² per day intravenously on days 1-5 and 8-12 of a 21-day cycle) in an upfront window; those with complete (CR) or partial response (PR) had VI incorporated into regimen UH1 (regimen UH2). The study was designed to detect improvement in outcomes of patients with stage II to IV DAWT compared with historical controls treated with regimen I.

RESULTS

Sixty-six eligible patients were enrolled. Of 14 patients with stage IV measurable disease who received VI, 11 (79%) achieved CR (n = 1) or PR (n = 10) after 2 cycles. Doses of doxorubicin, cyclophosphamide, and etoposide were reduced midstudy because of nonhematologic toxicity. Four patients (6%) died as a result of toxicity. Four-year event-free survival, relapse-free survival, and overall survival rates were 67.7% (95% CI, 55.9% to 79.4%), 72.9% (95% CI, 61.5% to 84.4%), and 73.7% (95% CI, 62.7% to 84.8%), respectively, compared with 57.5% (95% CI, 47.6% to 67.4%; P = .26), 57.5% (95% CI, 47.6% to 67.4%; P = .048), and 59.2% (95% CI, 49.4% to 69.0%; P = .08), respectively, in NWTS-5.

CONCLUSION

VI produced a high response rate in patients with metastatic DAWT. AREN0321 treatment seemed to improve outcomes for patients with stage II to IV DAWT compared with NWTS-5, but with increased toxicity. The UH2 regimen warrants further investigation with modifications to reduce toxicity.

Abstract 1345: Automated capture and analysis of circulating tumor cells across different types of tumors in pediatric cancer patients

The clinical utility of blood analysis such as circulating tumor cells (CTCs) has garnered increasing interest in recent years. However very few studies were conducted in pediatric cancer patients especially in brain tumor, osteosarcoma, and leukemia patients due to the lack of an effective tool to isolate/capture CTC from these patients. For example, only three independent studies were published to investigate CTC capture from adult brain tumor patients but zero studies were conducted with pediatric brain cancer patients. Our previous studies showed the high specificity of using cell surface vimentin (CSV) to identify and capture CTCs from various types of adult tumor patients using a manual isolation method. Here we present the first automated system for capturing CTCs across different types of pediatric tumors. This automated system utilizes the Abnova CytoQuest system loaded with the CSV antibody 84-1-coated microfluidic cassette for capturing CTCs from peripheral blood samples. This automated assay was very sensitive because as few as one tumor cell can be captured out from one million normal cells. Based on our preliminary study, our success rate for non-DIPG brain tumor, ALL, and AML patients is 100%. This success provides a potential opportunity for analyzing brain tumor genetic properties using blood samples instead of the invasive tumor biopsy; likewise, this high sensitivity assay opens up clinical opportunities to use this assay for transplant and treatment decision making.

Note: This abstract was not presented at the meeting.

Citation Format: Izhar S. Batth, Wafik Zaky, Soumen Khatua, Najat C. Daw, Kris M. Mahadeo, Sajad Khazal, Aisha Albert, Wilber Huang, Diva Chen, Jonathan B. Gill, Eugenie Kleinerman, Richard Gorlick, Shulin Li. Automated capture and analysis of circulating tumor cells across different types of tumors in pediatric cancer patients [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 1345.

Phase II trial of ixazomib combined with gemcitabine and doxorubicin in patients with SMARCB1-deficient kidney malignancies

TPS678

Background: SMARCB1 (also known as INI-1, hSNF5, or BAF47) is a potent tumor suppressor inactivated in all cases of renal medullary carcinoma (RMC) and renal cell carcinoma unclassified with medullary phenotype (RCCU-MP), as well as the majority of malignant rhabdoid tumors (MRT). These highly aggressive malignancies often occur in young patients (pts) and are associated with poor prognosis. There are currently no approved therapies targeting SMARCB1 defects. We previously showed that SMARCB1 loss induces a synthetically lethal vulnerability to perturbations of the cellular proteostasis machinery by proteasome inhibitors (Genovese et al. Nature, 542:362-366, 2017). The present study was designed to determine whether the addition of the second-generation proteasome inhibitor ixazomib to cytotoxic chemotherapy with gemcitabine and doxorubicin (IGD regimen) can improve outcomes of pts with aggressive SMARCB1-deficient kidney malignancies. Methods: This single-arm trial uses the Bayesian optimal phase II (BOP2) design (Heng et al. Stat Med 2017) to determine if the IGD regimen will improve the two co-primary endpoints of objective response rate (ORR) to 50% and 28-week disease control rate (DCR) to 30% compared with the historical ORR and 28-week DCR of 29% and 14%, respectively, achieved using gemcitabine plus doxorubicin alone as first-line or salvage therapy in pts with SMARCB1-negative RMC, RCCU-MP, and adult-onset kidney MRTs treated at our institution. Up to 30 pts aged ≥ 12 years old will be enrolled and any number of prior therapies is allowed. Ongoing monitoring for safety and futility will be implemented in 10-patient cohorts. If both the ORR and DCR improve to 50% and 30%, respectively, then there is only a 3.5% chance of stopping early and a 93.1% chance of claiming that IGD is efficacious. Secondary endpoints include progression-free survival, and overall survival. Tissue correlative analyses will be performed to determine whether tumors from pts responding to IGD have increased levels of endoplasmic reticulum stress markers involved in protein turnover. At the time of the abstract submission, 5 pts have been enrolled on this study. Clinical trial information: NCT03587662.

Alpha Particle Radium 223 Dichloride in High-risk Osteosarcoma: A Phase I Dose Escalation Trial

PURPOSE

The prognosis of metastatic osteosarcoma continues to be poor. We hypothesized that alpha-emitting, bone-targeting radium 223 dichloride (²²³RaCl₂) can be safely administered to patients with osteosarcoma and that early signals of response or resistance can be assessed by quantitative and qualitative correlative imaging studies and biomarkers.

PATIENTS AND METHODS

A 3+3 phase I, dose-escalation trial of ²²³RaCl₂ (50, 75, and 100 kBq/kg) was designed in patients with recurrent/metastatic osteosarcoma aged ≥15 years. Objective measurements included changes in standardized uptake values of positron emission tomography (PET; 18FDG and/or NaF-18) and single-photon emission CT/CT (99mTc-MDP) as well as alkaline phosphatase and bone turnover markers at baseline, midstudy, and the end of the study.

RESULTS

Among 18 patients enrolled (including 15 males) aged 15-71 years, tumor locations included spine (n = 12, 67%), pelvis (n = 10, 56%), ribs (n = 9, 50%), extremity (n = 7, 39%), and skull (n = 2, 11%). Patients received 1-6 cycles of ²²³RaCl₂; cumulative doses were 6.84-57.81 MBq. NaF PET revealed more sites of metastases than did FDG PET. One patient showed a metabolic response on FDG PET and NaF PET. Four patients had mixed responses, and one patient had a response in a brain metastasis. Bronchopulmonary hemorrhage from Grade 3 thrombocytopenia (N = 1) was a DLT. The median overall survival time was 25 weeks.

CONCLUSIONS

The first evaluation of the safety and efficacy of an alpha particle in high-risk osteosarcoma shows that the recommended phase II dose for ²²³RaCl₂ in osteosarcoma is 100 kBq/kg monthly (twice the dose approved for prostate cancer), with minimal hematologic toxicity, setting the stage for combination therapies.

Whole body magnetic resonance imaging (WB-MRI) and brain MRI baseline surveillance in TP53 germline mutation carriers: experience from the Li-Fraumeni Syndrome Education and Early Detection (LEAD) clinic

Individuals with Li-Fraumeni syndrome (LFS) have a significantly increased lifetime cancer risk affecting multiple organ sites. Therefore, novel comprehensive screening approaches are necessary to improve cancer detection and survival in this population. The objective of this study was to determine the diagnostic performance of whole body MRI (WB-MRI) and dedicated brain MRI screening as part of a comprehensive screening clinic called Li-Fraumeni Education and Early Detection (LEAD) at MD Anderson Cancer Center. Adult (≥21 year old) and pediatric (<21 year old) patients were referred to the LEAD clinic by healthcare providers or self-referred and screened at 6 month intervals. During the study period, 63 LFS individuals were seen in the LEAD clinic including 49 adults (11 male, 38 female) and 14 children (7 male, 7 female). Fifty-three of 63 potentially eligible individuals underwent baseline WB-MRI (41 adults and 12 children) with primary tumors detected in six patients, tumor recurrence in one patient and cancer metastases in one patient. Thirty-five of 63 patients (24 adults and 11 children) underwent baseline brain MRI with primary brain tumors detected in three individuals, also noted on subsequent WB-MRI scans. Three additional tumors were diagnosed that in retrospect review were missed on the initial scan (false negatives) and one tumor noted, but not followed up clinically, was prospectively found to be malignant. The high incidence of asymptomatic tumors identified in this initial screening (13%), supports the inclusion of WB-MRI and brain MRI in the clinical management of individuals with LFS.

Multi-level otsu method to define metabolic tumor volume in positron emission tomography

This study was to validate reliability and clinical utility of a PET tumor segmentation method using multi-level Otsu (MO-PET) in standard National Electrical Manufacturers Association (NEMA) image quality (IQ) phantom and patients with osteosarcoma. The NEMA IQ phantom was prepared with a lesion-to-background ratio (LBR) of either 8:1, 4:1, or 1.5:1. The artificial lesions in the phantom were segmented using MO-PET, gradient-based method (PETedge), relative threshold methods, and background threshold methods. Metabolic tumor volumes (MTVs) using MO-PET and PETedge were named as MTV (MO-PET) and MTV (PETedge), respectively. Among the MTVs using multiple methods, only MTV (MO-PET) and MTV (PETedge) showed excellent agreements with the actual volume of NEMA IQ phantom across the different LBRs (intraclass correlation coefficient, ICC = 0.987, 0.985 in LBR 8:1, 0.981, 0.993 in LBR 4:1 and 0.947, 0.994 in LBR 1.5:1). Repeated measurements of MTV (MO-PET) of the primary tumors showed excellent reproducibility with ICC of 0.994 (0.989-0.997) in patients with osteosarcoma. Also, MTV (MO-PET) was found to be predictive of Event Free Survival (EFS) [Hazard ratio (95% CI) = 6.1 (2.1-17.2), log rank P = 0.0003] in patients with osteosarcoma. We have validated in NEMA IQ phantom that the MTV (MO-PET) is accurate, and importantly, stable and consistent across a range of lesion sizes and LBRs representative of clinical tumor lesions. Furthermore, MTV (MO-PET) showed excellent reproducibility and was predictive for EFS in patients with osteosarcoma.

Health-Related Quality of Life and Survival Outcomes of Pediatric Patients With Nonmetastatic Osteosarcoma Treated in Countries With Different Resources

Purpose

Health-related quality of life (HRQOL) improves throughout treatment of patients with nonmetastatic osteosarcoma. We compared HRQOL for patients in the United States and Chile treated on an international trial (OS99) with polychemotherapy and surgery, and we assessed the relationships among HRQOL measures, event-free survival (EFS), and overall survival (OS).

Materials and Methods

Patients with newly diagnosed, localized osteosarcoma and their parents completed three HRQOL instruments (PedsQL v.4, PedsQL Cancer v.3, and Symptom Distress Scale [SDS]). Data were collected at four time points throughout therapy. Repeated measures models were used to investigate the effect of treatment site on instrument scores. The log-rank test examined the impact of treatment site on survival outcomes, and Cox proportional hazards regression models evaluated baseline HRQOL measures as predictors of EFS and OS.

Results

Of 71 eligible patients, 66 (93%) participated in the HRQOL studies in the United States (n = 44) and Chile (n = 22). The median age was 13.4 years (range, 5 to 23 years). Clinical characteristics were similar between treatment sites. US patients reported better scores for physical (P = .030), emotional (P = .027), and school functioning (P < .001). Chilean patients reported poorer scores for worry (P < .001) and nausea (P = .007). Patient and parent nausea scores were similar between patients treated in the United States and Chile by the end of therapy. Differences in symptom distress were not observed between the countries. Neither HRQOL measures nor treatment site were associated with EFS or OS.

Conclusion

Although significant differences in HRQOL were observed between countries, outcomes were similar, and HRQOL measures were not associated with prognosis.

Tumor thrombus in the large veins draining primary pelvic osteosarcoma on cross sectional imaging

PURPOSE

To evaluate the frequency of tumor thrombus in the large veins draining primary pelvic osteosarcoma on early cross-sectional imaging studies and its effect on patient survival.

MATERIALS AND METHODS

Our retrospective study included all patients with primary pelvic osteosarcoma treated at our facility between January 2000 and May 2014, who were ≤ 45 years of age, and had adequate imaging studies and clinical follow up. Four radiologists evaluated for tumor in the large draining veins on initial CT, MRI and PET/CTs. A consensus evaluation by the four radiologists together with findings on operative reports, pathology reports or follow-up imaging was used as the reference standard.

RESULTS

Thirty-nine patients with primary pelvic osteosarcoma met final inclusion criteria. Tumor thrombus was identified in the large draining veins in 10 of the 22 (45%) patients who underwent tumor resection and 10 of the 17 (59%) who did not. In the 22 patients who underwent tumor resection, tumor thrombus was significantly associated with worse overall survival (p = 0.03).

CONCLUSIONS

Tumor thrombus in the large draining veins is identified in a significant proportion of initial imaging studies in patients with pelvic osteosarcoma, and is associated with worse overall survival in patients who undergo tumor resection.

Multimodality Treatment of Desmoplastic Small Round Cell Tumor: Chemotherapy and Complete Cytoreductive Surgery Improve Patient Survival

Purpose: Desmoplastic small round cell tumor (DSRCT), which harbors EWSR1-WT1 t(11;22)(p13:q12) chromosomal translocation, is an aggressive malignancy that typically presents as intra-abdominal sarcomatosis in young males. Given its rarity, optimal treatment has not been defined.Experimental Design: We conducted a retrospective study of 187 patients with DSRCT treated at MD Anderson Cancer Center over 2 decades. Univariate and multivariate regression analyses were performed. We determined whether chemotherapy, complete cytoreductive surgery (CCS), hyperthermic intraperitoneal cisplatin (HIPEC), and/or whole abdominal radiation (WART) improve overall survival (OS) in patients with DSRCT. Critically, because our institutional practice limits HIPEC and WART to patients with less extensive, potentially resectable disease that had benefited from neoadjuvant chemotherapy, a time-variant analysis was performed to evaluate those adjunct treatment modalities.Results: The pre-2003 5-year OS rate of 5% has substantially improved to 25% with the advent of newer chemotherapies and better surgical and radiotherapy techniques (HR, 0.47; 95% CI, 0.29-0.75). Chemotherapy response (log rank P = 0.004) and CCS (log rank P < 0.0001) were associated with improved survival. Although WART and HIPEC lacked statistical significance, our study was not powered to detect their potential impact upon OS.Conclusions: Improved 3- and 5-year OS were observed following multidisciplinary treatment that includes Ewing sarcoma (ES)-based chemotherapy and complete tumor cytoreductive surgery, but few if any patients are cured. Prospective randomized studies will be required to prove whether HIPEC or WART are important. In the meantime, chemotherapy and CCS remain the cornerstone of treatment and provide a solid foundation to evaluate new biologically targeted therapies. Clin Cancer Res; 24(19); 4865-73. ©2018 AACR.

Prognostic Value of Metabolic and Volumetric Parameters of FDG PET in Pediatric Osteosarcoma: A Hypothesis-generating Study

Purpose To preliminarily assess the potential prognostic value of various fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) parameters before, during, and after neoadjuvant chemotherapy (NCT). Materials and Methods Thirty-four patients with osteosarcoma were enrolled prospectively from 2008 to 2012 and underwent FDG PET/computed tomography (CT) imaging before (baseline scan), during (interim scan) and after NCT (posttherapy scan). The study was approved by the institutional review board and informed consent was received from patients. Maximum and peak standardized uptake value (SUV_max and SUV_peak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured. Predictive value of FDG PET parameters for event-free survival (EFS) and overall survival (OS) were evaluated. Multivariable Cox regression analysis for EFS and OS was performed by using histologic response and initial presence of metastasis as covariates. Results At baseline scan, SUV_peak, MTV, and TLG were predictive of EFS (P = .006-.03) and OS (P = .001-.03) but not associated with histologic response. At interim and posttherapy scan, SUV_max, SUV_peak, MTV, and TLG were associated with histologic response (P = .0002-.04) and predictive of EFS (P = .004-.02) and OS (P = .001-.03). Multivariable Cox regression analysis revealed that the FDG PET parameters either at baseline, interim, or posttherapy were independently predictive of EFS and OS. In particular, baseline MTV was an independent predictor of EFS (hazard ratio, 5.0 [95% confidence interval {CI}: 1.5, 16.8]) and OS (hazard ratio, 29.4 [95% CI: 2.2, 392.2]). Conclusion SUV_peak, MTV, and TLG either at baseline, interim, or posttherapy were predictive of EFS and OS and may be useful prognostic biomarkers for osteosarcoma. ^© RSNA, 2018 Online supplemental material is available for this article.

18F-FDG PET/CT as an Indicator of Survival in Ewing Sarcoma of Bone

Objective: The existing literature of 18 F-FDG PET/CT in Ewing sarcoma investigates mixed populations of patients with both soft tissue and bone primary tumors. The aim of our study was to evaluate whether the maximum standardized uptake value (SUVmax) obtained with 18F-FDG PET/CT before and after induction chemotherapy can be used as an indicator of survival in patients with Ewing sarcoma originating exclusively in the skeleton.

Materials and Methods: A retrospective database search from 2004-2011 identified 28 patients who underwent 18 F-FDG PET/CT before (SUV1, n= 28) and after (SUV2, n=23) induction chemotherapy. Mean follow up was 3.3 years and median follow up for survivors was 6.3 years (range: 2.6-9.8 years). Multivariate and univariate Cox proportional hazard model was used to assess for correlation of SUV1, SUV2, and the change in SUVmax with overall survival (OS) and progression-free survival (PFS).

Results: Mean SUVmax was 10.74 before (SUV1) and after 4.11 (SUV2) induction chemotherapy. High SUV1 (HR = 1.05, 95% CI: 1.0-1.1, P = 0.01) and SUV2 (HR =1.2, 95% CI: 1.0-1.4, P = 0.01) were associated with worse OS. A cut off point of 11.6 was identified for SUV1. SUV1 higher than 11.6 had significantly worse OS (HR = 5.71, 95% CI: 1.85 - 17.61, P = 0.003) and PFS (HR = 3.16, 95% CI: 1.13 - 8.79, P = 0.03, P < 0.05 is significant).

Conclusion: 18F-FDG PET/CT can be used as a prognostic indicator for survival in primary Ewing sarcoma of bone.

A phase II trial evaluating the feasibility of adding bevacizumab to standard osteosarcoma therapy

Increased vascular endothelial growth factor (VEGF) expression in osteosarcoma correlates with a poor outcome. We conducted a phase II trial to evaluate the feasibility and efficacy of combining bevacizumab, a monoclonal antibody against VEGF, with methotrexate, doxorubicin and cisplatin (MAP) in patients with localized osteosarcoma. Eligible patients received two courses of MAP chemotherapy before definitive surgery at week 10. Bevacizumab (15 mg/kg) was administered 3 days before starting chemotherapy then on day 1 of weeks 3 and 5 of chemotherapy. After surgery, patients received MAP for a total of 29 weeks; bevacizumab was added every 2 or 3 weeks on day 1 of chemotherapy at least 5 weeks after surgery. Group sequential monitoring rules were used to monitor for unacceptable bevacizumab-related targeted toxicity (grade 4 hypertension, proteinuria or bleeding, grade 3 or 4 thrombosis/embolism, and grade 2-4 major wound complications). Thirty-one patients (median age 12.8 years) with localized osteosarcoma were enrolled. No unacceptable targeted toxicities were observed except for wound complications (9 minor and 6 major), which occurred in 15 patients; none required removal of prosthetic hardware or amputation. The estimated 4-year event-free survival (EFS) rate and overall survival rate were 57.5 ± 10.0% and 83.4 ± 7.8%, respectively. Eight (28%) of 29 evaluable patients had good histologic response (<5% viable tumor) to preoperative chemotherapy. The addition of bevacizumab to MAP for localized osteosarcoma is feasible but frequent wound complications are encountered. The observed histologic response and EFS do not support further evaluation of bevacizumab in osteosarcoma.

18F-FDG Uptake During Early Adjuvant Chemotherapy Predicts Histologic Response in Pediatric and Young Adult Patients with Osteosarcoma

The purpose of this study was to determine the relationship of ¹⁸F-FDG uptake in the primary tumor at diagnosis, during therapy, and after therapy with a histologic response and event-free survival in pediatric and young adult patients with osteosarcoma (OS). Methods: Serial (baseline and 5 and 10 wk after start of therapy) ¹⁸F-FDG PET/CT imaging was performed in patients with newly diagnosed OS treated uniformly in a therapeutic trial at a single institution. Whole-body images were obtained approximately 1 h after injection of ¹⁸F-FDG. Logistic regression was used to study the association of tumor uptake and changes in SUV_max between 0, 5, and 10 wk for both clinical endpoints. Results: Thirty-four patients (17 males; median age, 12.2 y; age range, 6.8-19.1 y) underwent PET imaging; 25 (74%) had localized disease. Primary tumor locations included the femur (n = 17; 50%), tibia (n = 9; 26%), and humerus (n = 5; 15%). Logistic regression showed that SUV_max at 5 wk (P = 0.034) and 10 wk (P = 0.022) and percentage change from baseline at 10 wk (P = 0.021) were highly predictive of a histologic response. Using SUV_max of 4.04 at week 5, SUV_max of 3.15 at week 10, and 60% decrease from baseline at week 10 as cutoff values, we determined that the respective sensitivities were 0.93, 0.93, and 0.79 and that the respective specificities were 0.53, 0.71, and 0.76. Conclusion: SUV_max on routine images at 5 or 10 wk and percentage change in SUV_max from baseline to week 10 were metabolic predictors of a histologic response in OS. These findings may be useful in the early identification of patients who are responding poorly to therapy and may benefit from a change in treatment.

A phase I, first-in-human, dose escalation study of intravenous TK216 in patients with relapsed or refractory Ewing sarcoma

TPS11626

Background: Ewing sarcoma (ES) is a rare cancer that affects children and young adults. Patients with recurrent/refractory ES have a poor prognosis (5-year survival 10-15%) with no improvement despite advances in cytotoxic and targeted therapies. Genomic rearrangements resulting in fusion proteins and over-expression of ets family transcription factors occur in 95% of ES. In particular, the EWS-FLI1 oncogenic fusion creates a constitutively active transcription factor that drives the malignant ES phenotype. Strategies to target the EWS-FLI1 fusion protein have been limited by lack of specificity. A promising approach is to target the interaction of the ets transcription factor with its critical protein partner, RNA helicase A (RHA). TK216 is a novel small-molecule that directly binds to EWS-FLI1 and inhibits its function by blocking binding to RHA. TK216 demonstrates potent anti-proliferative effects on ES cell lines and xenografts. Methods: We initiated a Phase 1, first-in-human, open-label, multi-center, dose-escalation/dose-expansion trial of TK216 in patients with recurrent/refractory ES who are ≥12 years of age (ClinicalTrials.gov: NCT02657005). TK216 is dosed based on body surface area and administered as a continuous intravenous infusion for 7 days followed by 14 days rest every 21 days. Treatment may continue in the absence of disease progression. One intrapatient dose escalation is allowed. Enrollment of 6 to 8 cohorts using a 3+3 dose-escalation design is anticipated. During dose expansion, a total of 18 patients with ES will be accrued at the recommended Phase 2 dose (RP2D). The primary objective of the study is to determine the maximum tolerated dose and RP2D of TK216. Secondary objectives are to assess the safety profile, pharmacokinetics, pharmacodynamics, and antitumor activity of TK216. Molecular assays will be performed to characterize EWS-FLI or EWS-ets abnormalities in archival tumor tissue. The overall response rate, duration of response, progression-free survival, and overall survival will be determined in the expansion cohort. Nine patients have been enrolled since June 2016. Accrual to cohorts 1, 2, and 3 completed and cohort 4 opened in January 2017. Clinical trial information: NCT02657005.

Analysis of osteosarcoma subtypes by clinical genomic testing to identify clinically actionable alterations

11019

Background: Genomic testing is being utilized with increasing frequency to identify matched therapies for patients (pts) with advanced disease; however, the utility of such testing has not been defined in osteosarcoma (OS). We report our experience with 36 pts with recurrent/metastatic OS who underwent testing on a genomic testing protocol, including actionable alterations across multiple histologic subtypes of OS. Methods: Standardized hotspot mutation analysis was performed in 36 pts with recurrent/metastatic OS, using either a 46-, 50-gene, or 128-gene CLIA certified multiplex platform. 12 pts had a 200-gene analysis on a companion research protocol. We used the Catalogue Of Somatic Mutations In Cancer (COSMIC) database to identify alterations that are in mutation hotspots in OS or in other cancers. Clinical outcomes were retrospectively collected. Histologic subtype classifications were made by an experienced sarcoma pathologist based upon the pre-treatment and resection specimens. Cases with only metastatic samples available were classified as “other high-grade osteosarcoma.” Additional clinical correlations are ongoing. Results: A total of 36 pediatric and adult pts were analyzed. All osteosarcomas were high grade; the most common osteosarcoma histologic subtypes were chondroblastic, osteoblastic, and other. Samples analyzed were from primary tumor in 15/36 (42%), with the remaining from metastatic specimens (58%). Mutations were identified in 26 pts (72%). The most common mutations were in TP53. An activating PIK3CA E545K mutation was found in chondroblastic OS. Other notable hotspot mutations include a GNAS R201 mutation in osteoblastic osteosarcoma and a KRASG12V mutation in a fibroblastic osteosarcoma. Conclusions: Clinical gene panel sequencing can identify a limited number of potentially actionable mutations in patients with osteosarcoma. Given the heterogeneity of osteosarcoma at the molecular level, clinical genomic testing may be warranted to identify patients for participation on matched clinical trials.

Ewing sarcoma family of tumors in children younger than 10 years of age

AIM

Few data exist regarding the clinical characteristics and outcome of young children with Ewing sarcoma family of tumors (ESFT).

METHODS

We reviewed the records of ESFT patients at our institution younger than 10 years of age at diagnosis.

RESULTS

Forty-two patients were identified. Median age was 6.4 years (range 0.6-9.5 years). Most patients had T2 (>5 cm) tumors (n = 31; 74%). Most common primary site was the extremity (n = 17; 41%). Seven patients (17%) had metastasis at diagnosis. For local tumor control, 20 patients had surgery only, 13 had radiation therapy only, and 6 had surgery plus radiation. Surgical margin status was negative in 19 patients (73%). Median follow-up was 4.7 years (range 0.7-29.7 years), and 5-year relapse-free survival (RFS) and overall survival (OS) estimates were 67% (95% CI: 53-84%) and 82% (95% CI: 71-95%), respectively. Metastasis at presentation was the only significant predictor for decreased RFS (P = 0.008) and OS (P = 0.01). A trend was seen for T2 tumors with worse OS (P = 0.09).

CONCLUSION

Patients younger than 10 years of age with ESFT may have a better OS than older patients, but further study of a homogeneously treated larger cohort is needed.

Prospective study of neuropathic pain after definitive surgery for extremity osteosarcoma in a pediatric population

BACKGROUND

Neuropathic pain (NP) after definitive surgery for extremity osteosarcoma (OS) has not been previously characterized. This study prospectively investigates the incidence, duration, and treatment of NP in limb sparing surgery and amputation groups.

PROCEDURE

In patients treated for OS on a chemotherapy and definitive surgery (limb sparing vs. amputation) protocol (OS08), we prospectively collected the following data: (i) demographical data (age, sex, race); (ii) NP time of onset and duration; and (iii) dose (starting, maximum) and duration of gabapentin, amitriptyline, and methadone treatment.

RESULTS

Thirty-seven patients underwent 38 definitive surgeries: limb sparing (26, 68.4%) or amputations (12, 31.6%). Localization included lower extremity (30, 81%), upper extremity (6, 16%), or pelvis (1, 3%). Thirty patients (81%) developed NP and 26 of them required NP-specific medications (87.7%). The mean [standard deviation (SD)] duration of NP was 6.5 weeks (7.2) (median 4.4, range 0.3-29.9). All 26 patients (27 surgeries) treated with NP medications received gabapentin, either as single therapy (65.4%) (17 patients, 18 surgeries), dual therapy with gabapentin and amitriptyline (five patients), or triple therapy with gabapentin, amitriptyline, and methadone (four patients). The mean starting (maximum) doses of gabapentin, amitriptyline, and methadone (mg/kg/day) were 20.2 (43.8), 0.5 (0.7), and 0.3 (0.3), respectively. The incidence and duration of NP, duration of treatment, and NP-specific dose regimens were similar in the limb sparing and the amputation groups.

CONCLUSIONS

NP after definitive surgery for OS is frequently encountered, can persist for a significant time, and NP outcomes are similar in limb sparing and amputation groups.

A phase II study of clinical activity of SCH 717454 (robatumumab) in patients with relapsed osteosarcoma and Ewing sarcoma

BACKGROUND

Robatumumab (19D12; MK-7454 otherwise known as SCH717454) is a fully human antibody that binds to and inhibits insulin-like growth factor receptor-1 (IGF-1R). This multiinstitutional study (P04720) determined the safety and clinical efficacy of robatumumab in three separate patient groups with resectable osteosarcoma metastases (Group 1), unresectable osteosarcoma metastases (Group 2), and Ewing sarcoma metastases (Group 3).

PROCEDURE

Robatumumab infusions were administered every 2 weeks and were well tolerated with minimal toxicity. Centrally reviewed response data were available for 144 patients.

RESULTS

Low disease burden was important for osteosarcoma response: three of 31 patients had complete response or partial response (PR) by Response Evaluation Criteria in Solid Tumors (RECIST) in resectable patients (Group 1) versus zero of 29 in unresectable patients (Group 2); median overall survival was 20 months in Group 1 versus 8.2 months in Group 2. In centrally reviewed patients with Ewing sarcoma with PET-CT data (N = 84/115), there were six PR, 23 stable disease, and 55 progression of disease by RECIST at 2 months. Patients with Ewing sarcoma had a median overall survival of 6.9 months. However, responding patients with Ewing sarcoma were allowed to continue on treatment after study closure. A minority of patients with metastatic Ewing sarcoma showed clinical responses and have remained healthy after receiving 25-115 doses of robatumumab with remissions of >4 years duration (N = 6).

CONCLUSIONS

These findings show that although the IGF-1R remains an attractive treatment target, additional research is needed to identify responders and/or means to achieve durable remissions in order to successfully exploit IGF-1R signal blockade in Ewing sarcoma (clinicaltrials.gov: NCT00617890).

IGF-1R and mTOR Blockade: Novel Resistance Mechanisms and Synergistic Drug Combinations for Ewing Sarcoma

BACKGROUND

Therapies cotargeting insulin-like growth factor receptor 1 (IGF-1R) and mammalian target of rapamycin (mTOR) have demonstrated remarkable, albeit short-lived, clinical responses in a subset of Ewing sarcoma (ES) patients. However, the mechanisms of resistance and applicable strategies for overcoming drug resistance to the IGF-1R/mTOR blockade are still undefined.

METHODS

To elucidate predominant mechanism(s) of acquired drug resistance while identifying synergistic drug combinations that improve clinical efficacy, we generated more than 18 ES cell lines resistant to IGF-1R- or mTOR-targeted therapy. Two small-molecule inhibitors of IGF-1R were chosen, NVP-ADW-742 (IGF-1R-selective) and OSI-906 (a dual IGF-1R/insulin receptor alpha [IR-α] inhibitor). Reverse-phase protein lysate arrays (RPPAs) revealed proteomic changes linked to IGF-1R/mTOR resistance, and selected proteins were validated in cell-based assays, xenografts, and within human clinical samples. All statistical tests were two-sided.

RESULTS

Novel mechanisms of resistance (MOR) emerged after dalotuzumab-, NVP-ADW-742-, and OSI-906-based targeting of IGF-1R. MOR to dalotuzumab included upregulation of IRS1, PI3K, and STAT3, as well as p38 MAPK, which was also induced by OSI-906. pEIF4E(Ser209), a key regulator of Cap-dependent translation, was induced in ridaforolimus-resistant ES cell lines. Unique drug combinations targeting IGF-1R and PI3K-alpha or Mnk and mTOR were synergistic in vivo and vitro (P < .001) as assessed respectively by Mantel-Cox and isobologram testing.

CONCLUSIONS

We discovered new druggable targets expressed by chemoresistant ES cells, xenografts, and relapsed human tumors. Joint suppression of these newfound targets, in concert with IGF-1R or mTOR blockade, should improve clinical outcomes.

Comparison of (18) F-FDG-PET-CT and Bone Scintigraphy for Evaluation of Osseous Metastases in Newly Diagnosed and Recurrent Osteosarcoma

BACKGROUND

Bone scintigraphy (BS) is used to detect osseous metastases in osteosarcoma. (18) F-fluorodeoxyglucose-positron emission tomography-computed tomography ((18) F-FDG-PET-CT) is being increasingly used for staging. We compared the sensitivity, specificity, and diagnostic accuracy of (18) F-FDG-PET-CT and BS for detecting osseous metastases in osteosarcoma.

METHODS

We retrospectively reviewed 39 patients with osteosarcoma who had paired PET-CT and BS at diagnosis and/or first recurrence from 2003 to 2012. Imaging studies were reviewed by two pediatric imaging specialists who were blinded to results of the opposing modality and reference standard. Reviewers categorized lesions as benign, malignant, or indeterminate. Reference standard for lesion histology was biopsy or clinical follow-up. Diagnostic performance of PET-CT, BS, and combined modalities were determined.

RESULTS

There were 40 examinations from 39 patients and 65 distant lesions were evaluated. Median age was 12 years (range 5-19 years). Four patients had 15 osseous metastases at diagnosis (two biopsied and 13 clinically), and two had five osseous metastases at recurrence (one biopsied and five clinically). For distant sites, sensitivity, specificity, and diagnostic accuracy were 79%, 89% and 86% for PET-CT, 32%, 96%, and 77% for BS, and 95%, 85%, and 88% for PET-CT/BS combined. Sensitivity of PET-CT was superior to BS (P = 0.035); combined imaging modalities were superior to BS (P < 0.001) but not better than PET-CT alone (P = 0.25). Specificity for BS approached significance compared to combined imaging (P = 0.063). Examination-based analysis yielded similar results between individual and combined imaging modalities.

CONCLUSIONS

(18) F-FDG-PET-CT demonstrated superior sensitivity over BS for detecting osseous metastases, supporting the use of (18) F-FDG-PET-CT for staging of osteosarcoma.

Local Control Modality and Outcome for Ewing Sarcoma of the Femur: A Report From the Children's Oncology Group

BACKGROUND

The choice of a local control (LC) modality for Ewing sarcoma (EWS) of the femur is controversial. This study aimed to determine the effect of LC modality on tumor LC and patient outcomes.

METHODS

The study reviewed the treatment and outcomes for 115 patients who had EWS of the femur treated with similar chemotherapy in three cooperative group trials. Patient outcomes were analyzed according to the LC modality using the log-rank test and the cumulative incidence of local or distant failure using competing risks regression.

RESULTS

The median age of the patients was 13 years. The most common tumor location was the proximal femur followed by the mid femur. For 55 patients with available data, the tumor was larger than 8 cm in 29 patients and 8 cm or smaller in 26 patients. For 84 patients (73 %), surgery only was performed, whereas 17 patients (15 %) had surgery plus radiation, and 14 patients (12 %) had radiation only. The 5-year event-free survival (EFS) rate was 65 % (95 % confidence interval [CI], 55-73 %), and the 5-year overall survival (OS) rate was 70 % (95 % CI, 61-78 %). Patient outcomes did not differ significantly according to tumor location within the femur (proximal, mid or distal) or tumor size (<8 vs ≥8 cm). The findings showed no statistically significant differences in EFS, OS, cumulative incidence of local failure, or cumulative incidence of distant failure according to LC modality (surgery, surgery plus radiation, or radiation).

CONCLUSIONS

The LC modality did not significantly affect disease outcome for EWS of the femur. Further study of treatment complications and functional outcome may help to define the optimal LC modality.