Citations

Proton therapy is an expanding radiotherapy modality in the United States and worldwide. With the number of proton therapy centers treating patients increasing, so does the need for consistent, high‐quality clinical commissioning practices. Clinical commissioning encompasses the entire proton therapy system's multiple components, including the treatment delivery system, the patient positioning system, and the image‐guided radiotherapy components. Also included in the commissioning process are the x‐ray computed tomography scanner calibration for proton stopping power, the radiotherapy treatment planning system, and corresponding portions of the treatment management system. This commissioning report focuses exclusively on intensity‐modulated scanning systems, presenting details of how to perform the commissioning of the proton therapy and ancillary systems, including the required proton beam measurements, treatment planning system dose modeling, and the equipment needed.

AbstractThis international multidisciplinary document intends to provide clinicians with evidence‐based practical patient‐centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

Abstract Objectives Pure erythroid leukemia (PEL) is exceptionally rare in the pediatric setting. Four pediatric PEL cases with t(1;16)(p31;q24) NFIA-CBFA2T3 were reported previously. We present a case of an infant with PEL presenting with erythroblastic sarcoma and harboring a novel t(1;8)(p31.3;q21.3) NFIA-RUNX1T1 fusion detected by RNA sequencing and conventional karyotype. Methods Bone marrow (BM) and abdominal mass biopsies from the patient were evaluated with extensive immunohistochemical, flow cytometric, cytogenetic, and molecular studies. Results The patient was a female infant who presented between 2 and 5 months of age with cytopenias and an enlarging abdominal mass. Blasts in the BM and abdominal mass expressed CD71 and CD117 with focal expression of CD43, E-cadherin, epithelial membrane antigen, and hemoglobin A. They were negative for additional myeloid, lymphoid, and nonhematolymphoid markers. These findings were most consistent with PEL and erythroblastic sarcoma. RNA sequencing revealed the novel NFIA-RUNX1T1 fusion. Conclusions Along with the previously reported PELs with NFIA-CBFA2T3 fusions, we describe a subset of PELs that occur in children, that frequently display extramedullary disease, and that harbor rearrangements of NFIA with core binding factor genes. We hypothesize that, together, these cases represent a rare but distinct clinicopathologic group of pediatric PELs with recurrent genetic abnormality.

Background: Abdominal aortic aneurysm (AAA) is an important cause of cardiovascular mortality; however, its genetic determinants remain incompletely defined. In total, 10 previously identified risk loci explain a small fraction of AAA heritability. Methods: We performed a genome-wide association study in the Million Veteran Program testing ≈18 million DNA sequence variants with AAA (7642 cases and 172 172 controls) in veterans of European ancestry with independent replication in up to 4972 cases and 99 858 controls. We then used mendelian randomization to examine the causal effects of blood pressure on AAA. We examined the association of AAA risk variants with aneurysms in the lower extremity, cerebral, and iliac arterial beds, and derived a genome-wide polygenic risk score (PRS) to identify a subset of the population at greater risk for disease. Results: Through a genome-wide association study, we identified 14 novel loci, bringing the total number of known significant AAA loci to 24. In our mendelian randomization analysis, we demonstrate that a genetic increase of 10 mm Hg in diastolic blood pressure (odds ratio, 1.43 [95% CI, 1.24–1.66]; P =1.6×10 −6 ), as opposed to systolic blood pressure (odds ratio, 1.06 [95% CI, 0.97–1.15]; P =0.2), likely has a causal relationship with AAA development. We observed that 19 of 24 AAA risk variants associate with aneurysms in at least 1 other vascular territory. A 29-variant PRS was strongly associated with AAA (odds ratio PRS , 1.26 [95% CI, 1.18–1.36]; P PRS =2.7×10 −11 per SD increase in PRS), independent of family history and smoking risk factors (odds ratio PRS+family history+smoking , 1.24 [95% CI, 1.14–1.35]; P PRS =1.27×10 −6 ). Using this PRS, we identified a subset of the population with AAA prevalence greater than that observed in screening trials informing current guidelines. Conclusions: We identify novel AAA genetic associations with therapeutic implications and identify a subset of the population at significantly increased genetic risk of AAA independent of family history. Our data suggest that extending current screening guidelines to include testing to identify those with high polygenic AAA risk, once the cost of genotyping becomes comparable with that of screening ultrasound, would significantly increase the yield of current screening at reasonable cost.

PurposeIn quantitative susceptibility mapping (QSM) using magnetic resonance imaging, image reconstruction methods usually aim at suppressing streaking artifacts. In this study, a streaking detection method is proposed for evaluating and optimizing quantitative susceptibility maps.MethodsNine healthy subjects participated in this study and underwent three‐dimensional multi‐echo gradient echo scans. Regularized iterative algorithm was used for reconstruction of tissue susceptibility maps in all subjects. Streaking detection was applied to evaluate streaking artifact in tissue susceptibility maps. In addition, an optimization process for QSM reconstruction by streaking detection was applied and was compared with matching noise level method.ResultsIt is shown that the proposed streaking detection technique effectively delineates streaking artifact in tissue susceptibility maps. In QSM reconstruction, optimization by streaking detection successfully determines the regularization factor that balances between streaking artifact suppression and tissue texture preservation. ROI analyses of brain tissue susceptibility show that optimization by streaking detection achieves results in good agreement with that from matching noise level method.ConclusionsStreaking detection enables direct visualization of streaking patterns in tissue susceptibility maps. It can be applied both for evaluating QSM reconstruction quality and for comparing different reconstruction algorithms. Furthermore, streaking detection can be incorporated into an optimization process of QSM reconstruction. Therefore, we conclude that the proposed method will add value to reconstruction of QSM.

Abstract Background: Obesity is a well established risk factor not only for increased prostate cancer incidence, but for poorer survival from prostate cancer. However, there is limited knowledge on the role of the circulating lipidome in prostate cancer. In order to target lipid metabolism optimally, it is critical to understand the spectrum of changes in circulating lipid profiles and the association with clinical outcome across the natural history of prostate cancer. Aim: To assess the relationship between the plasma lipidome and clinical outcome in localized and metastatic prostate cancer. Methods: Liquid chromatography-tandem mass spectrometry was used to quantitate over 500 lipid species in plasma samples from 3 cohorts (1) 389 men with localized prostate cancer, (2) 44 men with metastatic hormone-sensitive prostate cancer (mHSPC), and (3) 137 men with metastatic castration-resistant prostate cancer (CRPC). Associations between circulating lipids with metastatic relapse, androgen-deprivation therapy (ADT) failure or overall survival for each relevant disease stage were examined by latent class analysis and cox regression. Results: Circulating lipid profiles displaying elevated levels of ceramides were associated with metastatic relapse in localized prostate cancer (HR 5.8, 95% CI 3.0-11, P 1 × 10−6), early ADT failure in mHSPC (HR 2.4, 95% CI 1.1-5.3, P 0.03), and shorter overall survival in CRPC (HR 2.5, 95% CI 1.7-3.7, P 2 × 10−6). ADT failure in mHSPC and shorter overall survival in CRPC were also associated with elevated levels of other sphingolipids (sphingomyelins, hexosylceramides). The prognostic significance of the high risk lipid profiles in localized prostate cancer was independent of clinicopathological characteristics (lipid profile HR 4.7, 95%CI 2.4-9.3, P 7 × 10−6) when modeled with Gleason score (P<0.0001) and pathological stage (P<0.0001). Furthermore, the circulating lipid profiles were independent of metabolic factors (localized prostate cancer lipid profile HR 8.2, 95% CI 2.6-25, P 0.0003 when modeled with diabetes, statin, hypertension, body mass index [BMI]; CRPC lipid profile HR 2.6, 95% CI 1.7-3.8, P x10−6 when modeled with BMI). Conclusion: Elevated circulating ceramides are associated with poorer clinical outcomes across the natural history of prostate cancer (from localized to metastatic hormone-sensitive to metastatic castration resistant prostate cancer). This demonstrates that aberrant lipid metabolism in the patients occurs early in prostate cancer and could be therapeutically targeted in prospective clinical trials to improve prostate cancer outcomes. Citation Format: Lisa Glen Horvath, Hui-Ming Lin, Blossom Mak, Kate Mahon, Nicole Yeung, Maria Docanto, Peter Sutherland, andrew Shepherd, Winston Tan, Arun Azad, Manish Kohli, Peter Meikle, Lisa Butler. Lipidomic analysis of circulating lipids across the natural history of prostate cancer identifies aberrant ceramide metabolism [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4761.

Abstract More Americans die every year of lung cancer than any other cancer. While the environmental risks for lung cancer are well understood, the genetic risk factors for this disease are not, even though it has been shown that lung cancer risk aggregates in families. Segregation analyses have confirmed the likelihood of rare, highly penetrant variants affecting lung cancer. Family studies offer a unique opportunity to identify such rare risk variants. We have previously identified a genome-wide significant risk locus for lung cancer using multipoint linkage analysis in highly aggregated lung cancer families. In this study, we performed targeted sequencing on this 6q23-6q27 region on 75 individuals from the 9 most strongly linked families. Parametric two-point linkage analysis using an autosomal dominant model with 10% penetrance for carriers and a 1% phenocopy rate and disease allele frequency of 1% was performed for each family. While we did not find any genome-wide significant results in any of the individual families, we did observe several interesting potential rare risk variants. First, we observed that the significant signal previously observed on 6q is recapitulated in these data but the location of the peak LOD is highly heterogeneous across families and it is likely that each family has a different risk gene. While most of the highest LOD scores were in noncoding variants, we did observe exonic variants with the highest LOD scores in two families (44 and 42). Both variants were rare, with a minor allele frequency (MAF) of approximately 1% and were in LPA and GPR126 respectively. Both these genes have been implicated somatically in lung cancer, however this is the first time that they have been implicated in the germline. While the other families have their highest LOD scores in noncoding variants, some of these genes are also good potential candidate genes including PARK2 (family 30), GRM1 (family 47), and PDE10A (family 102). All three genes have been implicated in lung cancer in some capacity, and this is the first time that GRM1 and PDE10A have been implicated as germline mutations. Again, all these variants are rare (MAF ⇐ 0.01) in the general population, which makes sense for a potential highly penetrant risk variant. In this study, we have elucidated that a previously identified risk locus on 6q25 is heterogeneous in the nine most strongly linked families, with different families appearing to be carrying different risk variants. Many of the top variants in each family are rare variants that are in good potential causal genes that have been identified for the first time here as germline risk variants for lung cancer. Further functional annotation is underway for these variants and some additional linkage analyses using other penetrance matrices may also be performed. Citation Format: Anthony M. Musolf, Claire L. Simpson, Bilal A. Moiz, Mariza de Andrade, Diptasri Mandal, Colette Gaba, Ping Yang, Ming You, Elena Y. Kupert, Marshall W. Anderson, Ann G. Schwartz, Susan M. Pinney, Christopher I. Amos, Joan E. Bailey-Wilson. Highly aggregated lung cancer families reveal a heterogeneous cause for a previous linkage signal on 6q [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 37.

Abstract PARP inhibitor (PARPi) resistance in high-grade serous ovarian carcinoma (HGSOC) can be acquired as a result of restored homologous recombination (HR) due to secondary or reversion mutations in HR genes, such as BRCA1, BRCA2, and RAD51C, or due to loss of BRCA1 promoter methylation (meBRCA1). We have demonstrated that homozygous meBRCA1 can be lost or reverted to heterozygous methylation following treatment with platinum-based chemotherapy, resulting in HR-competent PARPi-resistant tumors. RAD51C promoter methylation (meRAD51C) is detected in approximately 2% of HGSOC cases and, as with meBRCA1, is associated with gene silencing and HR deficiency. We are exploring PARPi response in meRAD51C preclinical models to determine clinical relevance. Two patient-derived xenograft (PDX) models of HGSOC with RAD51C gene silencing caused by meRAD51C have distinct meRAD51C profiles (measured by methylation-specific high-resolution melt analysis and targeted bisulfite next-generation sequencing), and different responses to PARPi treatment pressure. PDX PH039 loses methylation and regains RAD51C expression after only 2 cycles of PARPi retreatment (niraparib), resulting in PARPi-refractory tumors by cycle 3-4. Illumina EPIC methylation array analysis of PH039 revealed increasing global methylation losses following each round of PARPi treatment. Lack of meRAD51C stability and rapid development of PARPi resistance in PH039 may be due to the high degree of meRAD51C heterogeneity within the tumor favoring selection of pre-existing HR-competent clones under PARPi pressure. In contrast, PDX 183 has a relatively homogeneous and stable meRAD51C profile. We have multiple examples of using unique PDX models to demonstrate various important features of PARPi resistance, including loss of promoter methylation for BRCA1 vs. RAD51C. Thus, meRAD51C confers response to PARPi in HGSOC, but PARPi treatment pressure can cause loss of methylation and drug resistance in some tumors. The contrasting PARPi responses of these PDX provide a platform for the study of meRAD51C stability in vivo and may present therapeutic opportunities to improve meRAD51C durability and PARPi responses in patients. Citation Format: Kasenija Nesic, Rachel M Hurley, Cordelia McGehee, Olga Kondrashova, Maria I. Harrell, Giada V. Zapparoli, Ashan Musafer, Ming E. Wong, John Weroha, Xiaonan Hou, Hu Li, Vivian Negron, Kevin Peterson, Paula Schneider, Elizabeth M. Swisher, Melissa Southey, Alexander Dobrovic, Matthew Wakefield, Scott H. Kaufmann, Clare L. Scott. DNA repair gene promoter methylation patterns adapt and influence PARP inhibitor response [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA02.