Clinical parameters affecting survival outcomes in patients with low-grade serous ovarian carcinoma: an international multicentre analysis

BACKGROUND

Women with low-grade ovarian serous carcinoma (LGSC) benefit from surgical treatment; however, the role of chemotherapy is controversial. We examined an international database through the Ovarian Cancer Association Consortium to identify factors that affect survival in LGSC.

METHODS

We performed a retrospective cohort analysis of patients with LGSC who had had primary surgery and had overall survival data available. We performed univariate and multivariate analyses of progression-free survival and overall survival, and generated Kaplan-Meier survival curves.

RESULTS

Of the 707 patients with LGSC, 680 (96.2%) had available overall survival data. The patients' median age overall was 54 years. Of the 659 patients with International Federation of Obstetrics and Gynecology stage data, 156 (23.7%) had stage I disease, 64 (9.7%) had stage II, 395 (59.9%) had stage III, and 44 (6.7%) had stage IV. Of the 377 patients with surgical data, 200 (53.0%) had no visible residual disease. Of the 361 patients with chemotherapy data, 330 (91.4%) received first-line platinum-based chemotherapy. The median follow-up duration was 5.0 years. The median progression-free survival and overall survival were 43.2 months and 110.4 months, respectively. Multivariate analysis indicated a statistically significant impact of stage and residual disease on progression-free survival and overall survival. Platinum-based chemotherapy was not associated with a survival advantage.

CONCLUSION

This multicentre analysis indicates that complete surgical cytoreduction to no visible residual disease has the most impact on improved survival in LGSC. This finding could immediately inform and change practice.

18F-DCFPyL PET/CT in advanced high-grade epithelial ovarian cancer: A prospective pilot study

Objectives

Glutamate carboxypeptidase-II (GCP-II), a zinc metalloenzyme that resides in cell membrane, has been reported as overexpressed in the neovasculature of ovarian cancers. The study objective was to determine whether GCP-II targeted imaging with ¹⁸F-DCFPyL PET/CT can detect disease sites in women with advanced high-grade serous ovarian cancer (HGSOC).

Materials and methods

Twenty treatment-naïve women with advanced HGSOC were recruited (median age 60 years). Prior to commencing therapy (primary cytoreductive surgery [n=9] or neoadjuvant chemotherapy [n=11]), subjects underwent routine staging with contrast-enhanced abdominopelvic CT (=CT), followed by ¹⁸F-DCFPyL PET/CT (=PET). CT and PET were reported independently using a standardized reporting template assessing 25 sites. The performance of PET was compared to CT in all subjects and to surgery and surgical histopathology in 9 patients who underwent primary cytoreductive surgery.

Results

Of the 25 sites assessed in 20 patients, CT detected disease in 292/500 (58.4%) locations and PET detected disease in 171/500 (34.2%). Compared to CT the sensitivity (95% CI) of PET to detect disease in the upper abdomen, the gastrointestinal tract or the peritoneum was 0.29 (0.20,0.40), 0.21 (0.11,0.33) and 0.74 (0.64,0.82), respectively. In the surgical cohort, 220 sites in 9 patients were evaluated. The sensitivity and specificity of CT and PET were 0.85 versus 0.54 (p<0.001) and 0.73 versus 0.93 (p<0.001), respectively.

Conclusion

Although ¹⁸F-DCFPyL has higher specificity than CT in detecting advanced HGSOC tumor sites, it detects less disease sites than CT, especially in the upper abdomen and along the gastrointestinal tract, likely limiting its clinical utility.

Clinical trial registration

ClinicalTrials.gov, NCT03811899.

Validation of the integrated prediction model algorithm for outcome of cytoreduction in advanced ovarian cancer

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Background: In advanced ovarian cancer, the decision for primary cytoreductive surgery(PCS) or neoadjuvant chemotherapy(NACT) remains a challenge and may impact survival. We previously developed the integrated prediction model(IPM) using a 4-step algorithm of unresectable stage IVb, patient factors, surgical resectability and surgical complexity to predict outcome of optimal cytoreduction in advanced epithelial ovarian cancer(AEOC) and triage patients to NACT or PCS. The objective of the current study was to validate this model on a retrospective historical cohort of patients. Methods: This is a retrospective cohort study of 107 patients with AEOC treated at the Princess Margaret Cancer Centre between January 2017 and September 2018 undergoing PCS or NACT. All diagnostic imaging was retrospectively reviewed to assign surgical resectability score (SRS) for sites of disease and the surgical complexity score (SCS) for procedures anticipated to be required to achieve optimal cytoreduction based on pre-operative imaging. Those scores were modified from previously validated tools. Patient factors (PF) included age, ECOG and albumin. We previously developed an IPM algorithm to achieve outcome of optimal cytoreduction and determined cut-offs using the Youden index J. Triaging patients to PCS without stage IVb unresectable disease, PF≤ 2, SRS≤5 and SCS≤ 9 led to an 85% specificity and 75% accuracy for outcome of optimal cytoreduction < 1 cm. The current validation study was performed reporting sensitivity, specificity, negative (NPV) and positive predictive value (PPV) on an external cohort. Results: Among 107 patients, 61 had PCS and 46 had NACT followed by ICS. Patients treated with NACT were significantly older (63.5 vs 61 years, p = 0.037), more likely stage IV (52% vs 18%, p < 0.001), had a higher proportion of ECOG > 1 (30% vs 11%, 0.045), a lower pre-operative album (37 vs 40, p < 0.001) and higher CA-125 (970 vs 227.5, p < 0.001) compared to PCS. They also had higher PF (2 vs 0, p = 0.013), SRS (4 vs 1, p < 0.001) and SCS (8 vs 5, p = < 0.001). There was no significant difference in outcome of cytoreduction; the optimal cytoreduction rate was 85% vs 87%, p = 0.12 between PCS and ICS patients. In this validation cohort, triaging patients without unresectable stage IVb disease, PF≤ 2, SRS≤ 5 and SCS≤ 9 to PCS had a sensitivity of 91% to correctly identify patients who will have optimal cytoreduction of < 1 cm at PCS and a specificity of 81%. The PPV was 83%, NPV was 90% and accuracy was 86%. Application of the IPM would have prevented 5 suboptimal patients and correctly triaged them to NACT. Conclusions: We validated a triage algorithm integrating patient factors, surgical complexity and surgical resectability for patients with AEOC to achieve optimal cytoreduction at PCS with high sensitivity and specificity. This may therefore be used in a clinical setting to decide between PCS and NACT.

Risk reduction strategies for BRCA1/2 hereditary ovarian cancer syndromes: a clinical practice guideline

OBJECTIVE

The purpose of this guideline is to make recommendations regarding the care of women who harbour a pathogenic or likely pathogenic variant in BRCA1 and BRCA2.

METHODS

Draft recommendations were formulated based on evidence obtained through a systematic review of RCTs, comparative retrospective studies and guideline endorsement. The draft recommendations underwent an internal review by clinical and methodology experts, and an external review by clinical practitioners.

RESULTS

The literature search yielded 1 guideline, 5 systematic reviews, and 15 studies that met the eligibility criteria.

CONCLUSIONS

In women who harbour a pathogenic or likely pathogenic variant in BRCA1 and BRCA2 screening for ovarian cancer is not recommended. Risk-reducing surgery is recommended to reduce the risk of ovarian cancer. In the absence of contraindications, premenopausal women undergoing RRSO should be offered hormone therapy until menopause. Systemic hormone replacement therapy, is not recommended for women who have had a personal history of breast cancer. RRSO should be considered for breast cancer risk reduction in women younger than 50 years. After a breast cancer diagnosis, RRSO for breast cancer mortality reduction can be considered within two years to women who harbour a pathogenic or likely pathogenic variant in BRCA1 if younger than the recommended age range for ovarian cancer risk reduction. RRSO before the age of 40 and specifically for breast cancer treatment in BRCA2 should be considered only if recommended by their breast cancer oncologist. Following RRSO, it is not recommended to do surveillance for peritoneal cancer.

Comparison of two multiplexed technologies for profiling >1,000 serum proteins that may associate with tumor burden

Background: In this pilot study, we perform a preliminary comparison of two targeted multiplex proteomics technologies for discerning serum protein concentration changes that may correlate to tumor burden in ovarian cancer (OC) patients. Methods: Using the proximity extension assay (PEA) and Quantibody® Kiloplex Array (QKA), we measured >1,000 proteins in the pre-surgical and post-surgical serum from nine OC patients (N=18 samples). We expect that proteins that have decreased significantly in the post-surgical serum concentration may correlate to tumor burden in each patient. Duplicate sera from two healthy individuals were used as controls (N=4 samples). We employed in-house ELISAs to measure five proteins with large serum concentration changes in pre- and post-surgical sera, from four of the original nine patients and the two original controls. Results: Both platforms showed a weak correlation with clinical cancer antigen 125 (CA125) data. The two multiplexed platforms showed a significant correlation with each other for >400 overlapping proteins. PEA uncovered 15 proteins, while QKA revealed 11 proteins, with more than a two-fold post-surgical decrease in at least six of the nine patients. Validation using single enzyme-linked immunosorbent assays (ELISAs) showed at least a two-fold post-surgical decrease in serum concentration of the same patients, as indicated by the two multiplex assays. Conclusion: Both methods identified proteins that had significantly decreased in post-surgical serum concentration, as well as recognizing proteins that had been implicated in OC patients. Our findings from a limited sample size suggest that novel targeted proteomics platforms are promising tools for identifying candidate serological tumor-related proteins.  However further studies are essential for the improvement of accuracy and avoidance of false results.

The correlation between BRCA status and surgical cytoreduction in high-grade serous ovarian carcinoma

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Background: High grade serous ovarian cancers (HGSC) with BRCA mutation are biologically unique, with distinct molecular and clinical behaviour from sporadic cases. It is unclear if these biological differences translate to favorable outcomes at the time of primary cytoreductive surgery (PCS). The aim of this study is to compare the amount of residual disease following PCS in BRCA-mutated (BRCAm) and wildtype (BRCAwt) HGSC, and to assess whether BRCA status is an independent predictor of residual disease. Methods: We conducted a retrospective analysis of patients with HGSC with known germline and somatic BRCA mutation status, treated with PCS from 2000 to 2017. We compared the cytoreduction outcomes between the BRCAm and the BRCAwt cohorts and built a predictive model to assess whether BRCA status was associated with amount of residual disease at the time of PCS. Results: Of 355 women, 144 harbored germline or somatic BRCA mutations (41%) and 211 were BRCAwt (59%). BRCAm women tended to be younger (54 vs. 59; p < 0.001), but there were no differences between the two groups in stage, disease burden at presentation, surgical complexity score, length of surgery, or perioperative complications. The BRCAm group had a higher rate of complete cytoreduction to no residual disease (0mm) [75% vs. 54%], and a lower rate of optimal cytoreduction (1-9mm) [16% vs. 34%] or suboptimal cytoreduction (≥10mm) [9% vs. 12%] (p < 0.001). In our predictive model, after accounting for length of surgery, CA-125 level, stage, disease scores and surgical complexity scores, BRCAm status was predictive of complete cytoreduction to 0mm residual disease (OR 4.78; 95% CI 2.32-9.85; p < 0.001). Conclusions: BRCA status is predictive of complete cytoreduction at time of PCS in HGSC. Timely availability of BRCA testing is paramount as it may aid in the therapeutic decision making between PCS or neoadjuvant chemotherapy in women with newly diagnosed HGSC.

Performance characteristics of brief family history questionnaire to screen for Lynch syndrome in women with newly diagnosed ovarian cancers

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Background: Ovarian cancer (OC) is the third most common Lynch syndrome (LS)-associated cancer in women but there is no established screening strategy to identify LS in this population. An adequate family history may identify patients suspected of LS, prompting a referral to genetic assessment. We have previously validated the 4-item brief Family History Questionnaire (bFHQ) in endometrial cancers. The objective of this study was to assess whether bFHQ can be used as a screening tool to identify women with OC at risk of LS. Methods: Prospective cohort study recruited women with newly diagnosed non-serous/non-mucinous OC from three cancer centers in Ontario, Canada. Participants completed bHFQ, extended Family History Questionnaire (eFHQ; encompassing Amsterdam II criteria, Society of Gynecologic Oncology 20-25% criteria and Ontario Ministry of Health criteria), immunohistochemistry (IHC) for mismatch repair (MMR) proteins and universal germline testing for LS. The performance characteristics were compared between bFHQ, eFHQ, and IHC. Results: Of 215 participants, 169 (79%) were evaluable with both bFHQ and germline mutation status; 12 of these 169 were confirmed to have LS (7%). Nine of 12 patients (75%) with LS were correctly identified by bFHQ, compared to 6 of 11 (55%) by eFHQ and 11 of 13 (85%) by IHC. The sensitivity, specificity, positive predictive values and negative predictive values of bFHQ were 75%, 66%, 15% and 98%, compared to 55%, 92%, 35% and 96% for eFHQ and 85%, 90%, 39% and 99% for IHC respectively. IHC was the most sensitive and specific approach. The 4-item bFHQ was more sensitive than eFHQ and took less than 10 minutes for each patient to complete. Conclusions: Patient-administered bFHQ may serve as an adequate screening tool to triage women with OC for further genetic assessment for LS, especially in centers without access to universal tumor testing for IHC for MMR.[Table: see text]

Tumor and germline next generation sequencing in high grade serous cancer: experience from a large population-based testing program

The aim of this study was to determine the prevalence of somatic and germline pathogenic variants (PVs) in high‐grade serous cancer (HGSC) and to demonstrate the technical feasibility and effectiveness of a large‐scale, population‐based tumor testing program. It involved a retrospective review of genetic test results in 600 consecutive HGSC tumor samples and a subsequent comparison of germline and tumor results in a subset of 200 individuals. Tumor testing was successful in 95% of samples (570/600) with at least one BRCA1/2 PV identified in 16% (93/570) of cases. Among the 200 paired cases, BRCA1/2 PVs were detected in 38 tumors (19%); 58% were somatic (22/38); and 42% were germline (16/38). There was 100% concordance between germline and tumor test results. This is the largest series of BRCA1/2 testing in HGSC (tumor‐only and paired cohorts), reported to date, and our data show that an effectively designed and validated population‐based tumor testing program can be used to determine both treatment eligibility and hereditary cancer risk.

Abstract 5144: Exploring the potential of a novel multiplex proteomics technology to identify personalized biomarkers of tumor burden in ovarian cancer patients

Objective: Owing to tumor heterogeneity, we hypothesize that each tumor secretes a unique mixture of tumor-related proteins into the bloodstream, which when quantified can serve as personalized markers of tumor load. We previously introduced the concept of "personalized tumor markers", which are highly sensitive for monitoring tumor load in a small subpopulation (5-30%) of patients. Screening against a robust panel of such personalized markers could identify the most effective markers of relapse in each patient. With the advent of multiplex proteomics technologies, for the first time we can screen serum for tumor-related proteins in individual patients. In this pilot study, we explored the potential of one of the leading new multiplex proteomics technologies for identifying personalized markers of tumor burden in the most common and deadliest type of ovarian cancer - high grade serous carcinoma (HGSC). Serum CA125 is the only widely used marker for HGSC but it is not informative of relapse in 30-60% of cases. With up-and-coming immunotherapies and precision medicines, there is a timely need for personalized markers to monitor for relapse and find the optimal timing for 2nd-line treatment in each patient.

Methods: We leveraged the multiplex immuno-PCR assay, Proseek Panels (Olink, Sweden), to concurrently measure 1,196 proteins in sera obtained pre- and post-surgically from 10 HGSC patients. Sera from two healthy individuals, with blinded technical duplicates, were used as controls. To validate the multiplexed results, we used independent, clinical grade ELISA immunoassays to measure three candidate proteins in sera collected pre- and post-surgically from five of the same 10 HGSC patients.

Results: Scatterplot analysis of 1,196 protein measurements in the technical duplicates showed high correlation and excellent assay precision. For candidate selection, we eliminated proteins that showed greater than two-fold change in the controls. We identified a panel of eight proteins that dropped more than 10-fold post-surgery in at least two patients. The panel as a whole was informative of tumor burden for 80% (8/10) of the patients tested. Using independent ELISAs, we observed high concordance in the post-surgical fold decrease between the Proseek panels and ELISA results, confirming the reliability of the novel platform. Further literature search demonstrated the relevance to tumorigenesis and ovarian cancer for the eight candidate personalized tumor markers.

Significance: With future validation in larger, longitudinal studies, our goal is to develop a panel of personalized HGSC biomarkers of relapse to aid in individualizing patient monitoring and ameliorating survival outcome. Our study also showed the utility of an innovative high throughput biotechnology that is promising for measuring tumor-derived proteins, which can be adapted for a myriad of biomarker studies, particularly in prevalent cancers with no reliable serum biomarkers such as lung cancer.

Citation Format: Annie Ren, Ioannis Prassas, Antoninus Soosaipillai, Marcus Bernardini, Vathany Kulasingam, Eleftherios Diamandis. Exploring the potential of a novel multiplex proteomics technology to identify personalized biomarkers of tumor burden in ovarian cancer patients [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 5144.

Long-term survival outcomes of intravenous versus intraperitoneal chemotherapy in the treatment of advanced ovarian cancer

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Background: The role of intraperitoneal (IP) chemotherapy in the management of advanced ovarian cancer has been questioned given emerging evidence showing lack of survival benefits. The objective of this study was to compare the long-term survival associated with IP chemotherapy at a tertiary cancer center. Methods: We reviewed the long-term survival records of 271 women with stage IIIC or IV high-grade serous ovarian cancer treated with primary cytoreductive surgery (PCS) followed by IP or intravenous (IV) chemotherapy between 2001-2015 with a minimum follow-up of 4 years. 5-year progression free (PFS) and overall survival (OS) rates were compared using Kaplan-Meier survival analysis and covariates were evaluated using Cox regression analysis. Results: Women who received IP chemotherapy after PCS (n = 91) were more likely to have undergone aggressive surgery (p < 0.001), longer surgery (p < 0.001), and had no residual disease (p < 0.001) compared to the IV arm (n = 180). Median follow-up was 51.6 months. Five-year PFS was 19% vs. 18% (p = 0.63) and OS was 73% vs. 44% (p = 0.00016) in the IP vs. IV arms, respectively. After controlling for covariates in a multivariable model, the use of IP was no longer a significant predictor of OS in the entire cohort (p = 0.12). In patients with 0mm residual disease, PFS was 28% vs. 26% (p = 0.67) and OS was 81% vs. 60% (p = 0.059) in IP (n = 61) vs. IV (n = 69), respectively. In patients with residual of 1-9mm, PFS was 30% vs. 48% (p = 0.076) and OS was 60% vs. 43% (p = 0.74) in IP (n = 29) vs. IV (n = 31), respectively. Conclusions: IP chemotherapy showed a trend towards improved survival over conventional IV chemotherapy, especially in patients with no residual disease. Given the retrospective nature and small numbers in this study, prospective non-randomized cohort studies are warranted to evaluate the role of IP chemotherapy in advanced ovarian cancer.

Abstract AP17: MOLECULAR AND FUNCTIONAL HETEROGENEITY OF CANCER ASSOCIATED FIBROBLASTS IN HIGH-GRADE SEROUS OVARIAN CANCER

High grade serous ovarian cancer (HGSC) is typically diagnosed at an advanced stage and the vast majority of patients relapse and die within 5 years of diagnosis. Significant clinical problems in HGSC include wide-spread abdominal dissemination of disease and chemotherapy resistance. Cancer-associated fibroblasts (CAFs) have been shown to play a role in promotion of cancer cell proliferation and invasion, and mediation of chemotherapy resistance. To interrogate the molecular properties of CAFs in HGSC we used fluorescence activated cell sorting to isolate CAFs directly from primary tumor samples and performed gene expression profiling. We found that patients stratify into two classes based on their CAF gene signatures: One with high expression of Fibroblast Activation Protein (FAP-High; FH) and one with low expression of FAP (FAP-Low; FL). FH CAFs express classical CAF genes whereas FL CAFs possesses a preadipocyte-like molecular signature. The FL phenotype has remained largely unnoticed as it is generally out-competed in vitro by FH cells when grown under classical CAF culture conditions. Patients from The Cancer Genome Atlas (TCGA), as well as from our own institute, can be stratified into FH and FL subtypes; in both cohorts patients with FH CAFs have a significantly shorter disease-free and overall survival. In vitro and in vivo functional assays performed with isolated CAFs of both types indicate that FH CAFs aggressively promote proliferation, invasion and therapy resistance of cancer cells, whereas FL CAFs do not. Finally, we identified TCF21, a transcriptional repressor, as a FL-specific transcription factor. Analysis of published TCF21 ChIP-Seq data indicates that TCF21 targets a large number of genes specific to FH CAFs. Overexpression of TCF21 in FH CAFs partially reversed their ability to promote cancer cell invasion and tumor growth. Our discovery of CAF heterogeneity in HGSC highlights the need to personalize patient treatment with respect to both cancer and stromal phenotypes. FH patients may benefit from inhibition of cancer-stroma interactions or from epigenetic modulators that reprogram cancer-promoting FH CAFs into the non-supportive FL state.

Citation Format: Ali Hussain, Veronique Voisin, Stephanie Poon, Jalna Meens, Julia Dmytryshyn, Josh Paterson, Marcus Bernardini3, Gary Bader, Benjamin G Neel, Laurie E Ailles. MOLECULAR AND FUNCTIONAL HETEROGENEITY OF CANCER ASSOCIATED FIBROBLASTS IN HIGH-GRADE SEROUS OVARIAN CANCER [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP17.

ABCB1 c.-6-180T>G polymorphism and clinical risk factors in a multi-breed cohort of dogs with refractory idiopathic epilepsy

Epilepsy is the most common chronic neurological disorder in dogs. Approximately 20-30% of dogs do not achieve satisfactory seizure control with two or more anti-epileptic drugs at appropriate dosages. This condition, defined as refractory epilepsy, is a multifactorial condition involving both acquired and genetic factors. The P glycoprotein might play and important role in the pathophysiological mechanism and it is encoded by the ABCB1 gene. An association between a single nucleotide variation of the ABCB1 gene (c.-6-180T>G) and phenobarbital resistance has previously been reported in a Border collie population with idiopathic epilepsy. To date, the presence and relevance of this polymorphism has not been assessed in other breeds. A multicentre retrospective, case-control study was conducted to investigate associations between ABCB1 c.-6-180T>G, clinical variables, and refractoriness in a multi-breed population of dogs with refractory idiopathic epilepsy. A secondary aim was to evaluate the possible involvement of the ABCB1 c.-6-180T>G single nucleotide variation this population. Fifty-two refractory and 50 responsive dogs with idiopathic epilepsy were enrolled. Of these, 45 refractory and 50 responsive (control) dogs were genotyped. The G allele was found in several breeds, but there was no evidence of association with refractoriness (P=0.69). The uncertain role of the c.-6-180T>G variation was further suggested by an association between the T/T genotype with both refractoriness and responsiveness in different breeds. Furthermore, high seizure density (cluster seizure) was the main clinical risk factor for refractory idiopathic epilepsy (P=0.003).

Experimental Observation of Proton Bunch Modulation in a Plasma at Varying Plasma Densities

We give direct experimental evidence for the observation of the full transverse self-modulation of a long, relativistic proton bunch propagating through a dense plasma. The bunch exits the plasma with a periodic density modulation resulting from radial wakefield effects. We show that the modulation is seeded by a relativistic ionization front created using an intense laser pulse copropagating with the proton bunch. The modulation extends over the length of the proton bunch following the seed point. By varying the plasma density over one order of magnitude, we show that the modulation frequency scales with the expected dependence on the plasma density, i.e., it is equal to the plasma frequency, as expected from theory.

Experimental Observation of Plasma Wakefield Growth Driven by the Seeded Self-Modulation of a Proton Bunch

We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of 2.1×10^{14} and 7.7×10^{14}  electrons/cm^{3}. We show that these wakefields periodically defocus the proton bunch itself, consistently with the development of the seeded self-modulation process. We show that the defocusing increases both along the bunch and along the plasma by using time resolved and time-integrated measurements of the proton bunch transverse distribution. We evaluate the transverse wakefield amplitudes and show that they exceed their seed value (<15  MV/m) and reach over 300  MV/m. All these results confirm the development of the seeded self-modulation process, a necessary condition for external injection of low energy and acceleration of electrons to multi-GeV energy levels.

Acceleration of electrons in the plasma wakefield of a proton bunch

High-energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. To increase the energy of the particles or to reduce the size of the accelerator, new acceleration schemes need to be developed. Plasma wakefield acceleration^1–5, in which the electrons in a plasma are excited, leading to strong electric fields (so called ‘wakefields’), is one such promising acceleration technique. Experiments have shown that an intense laser pulse^6–9 or electron bunch^10,11 traversing a plasma can drive electric fields of tens of gigavolts per metre and above—well beyond those achieved in conventional radio-frequency accelerators (about 0.1 gigavolt per metre). However, the low stored energy of laser pulses and electron bunches means that multiple acceleration stages are needed to reach very high particle energies^5,12. The use of proton bunches is compelling because they have the potential to drive wakefields and to accelerate electrons to high energy in a single acceleration stage¹³. Long, thin proton bunches can be used because they undergo a process called self-modulation^14–16, a particle–plasma interaction that splits the bunch longitudinally into a series of high-density microbunches, which then act resonantly to create large wakefields. The Advanced Wakefield (AWAKE) experiment at CERN^17–19 uses high-intensity proton bunches—in which each proton has an energy of 400 gigaelectronvolts, resulting in a total bunch energy of 19 kilojoules—to drive a wakefield in a ten-metre-long plasma. Electron bunches are then injected into this wakefield. Here we present measurements of electrons accelerated up to two gigaelectronvolts at the AWAKE experiment, in a demonstration of proton-driven plasma wakefield acceleration. Measurements were conducted under various plasma conditions and the acceleration was found to be consistent and reliable. The potential for this scheme to produce very high-energy electron bunches in a single accelerating stage²⁰ means that our results are an important step towards the development of future high-energy particle accelerators^21,22.

Electron acceleration to very high energies is achieved in a single step by injecting electrons into a ‘wake’ of charge created in a 10-metre-long plasma by speeding long proton bunches.

Intradural extramedullary granular cell tumour in a cat

A 7-year-old domestic shorthair cat was evaluated for progressive paraparesis, inability to jump, a paralysed tail and inability to void the bladder. Neurologic examination was consistent with a L4-S3 localisation. Survey radiographs of the lumbar vertebral column revealed L4-L7 vertebral body remodelling. A pre-contrast T1-weighted hyperintense, diffusely enhancing intradural lesion extending from L4 to S1 vertebral bodies was detected by MRI. Large, mesenchymal, round-to-polygonal cells arranged in nests or sheets were found on histologic examination at post mortem. These cells were characterised by abundant intracytoplasmic PAS-positive, diastase-resistant granules and positive immunoexpression of vimentin, S-100, neuron-specific enolase and desmin. This is the first report of a spinal granular cell tumour in a cat.

Analyses of germline variants associated with ovarian cancer survival identify functional candidates at the 1q22 and 19p12 outcome loci

We previously identified associations with ovarian cancer outcome at five genetic loci. To identify putatively causal genetic variants and target genes, we prioritized two ovarian outcome loci (1q22 and 19p12) for further study. Bioinformatic and functional genetic analyses indicated that MEF2D and ZNF100 are targets of candidate outcome variants at 1q22 and 19p12, respectively. At 19p12, the chromatin interaction of a putative regulatory element with the ZNF100 promoter region correlated with candidate outcome variants. At 1q22, putative regulatory elements enhanced MEF2D promoter activity and haplotypes containing candidate outcome variants modulated these effects. In a public dataset, MEF2D and ZNF100 expression were both associated with ovarian cancer progression-free or overall survival time. In an extended set of 6,162 epithelial ovarian cancer patients, we found that functional candidates at the 1q22 and 19p12 loci, as well as other regional variants, were nominally associated with patient outcome; however, no associations reached our threshold for statistical significance (p<1×10-5). Larger patient numbers will be needed to convincingly identify any true associations at these loci.

Phase II open-label randomized multi-centre study of neoadjuvant olaparib in patients (pts) with platinum sensitive (PS) relapsed high grade serous ovarian cancer (OC): The NEO trial

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Background: Olaparib is a PARP inhibitor with clinical benefit in relapsed OC, especially in pts with germline BRCA1/2 mutation ( gBRCA). Study 19 (NCT00753545) found a progression free survival (PFS) gain from maintenance olaparib, post chemotherapy for PS relapse. Olaparib treatment in gBRCA OC pts relapsing post ≥ 3 prior chemotherapy regimens gave a response rate (RR) of 46% in the PS subgroup (Study 42; NCT01078662). Efficacy of olaparib may extend to OC with homologous recombination DNA repair pathway deficiency (HRD); susceptible to synthetic lethality from PARP inhibition. NEO [NCT02489006] is a window of opportunity study to assess tumor heterogeneity and the pharmacodynamic effects of olaparib given prior to surgery in PS OC, analyse the tumor genomic landscape pre and post olaparib, and assess for predictive biomarkers beyond BRCA mutation. Methods: This phase 2 study enrols pts with high grade serous OC, primary peritoneal or fallopian tube cancer with a progression free interval of ≥6 months and sensitive to their last line of platinum therapy. Pts must be suitable for secondary debulking surgery and agree to pre-operative tumour biopsy. All pts receive olaparib tablets 300mg po bid for 6 ± 2 weeks pre-surgery. Post-operatively, pts are randomised 1:1 to olaparib or 6 cycles of platinum-based chemotherapy followed by maintenance olaparib. The primary endpoint is the degree of PAR and PARP-1 inhibition in the blood and tumor following pre-operative olaparib in PS relapsed OC. Clinical efficacy is assessed by RR (RECIST 1.1), CA125, PFS and PFS2. Translational studies include next generation sequencing HRD panel to assess for somatic and germline mutations including RAD51B/C/D, PPM1D, FANCM, BRIP1, PALB2 and BARD1; evaluation of gene expression change in tumor tissue pre and post olaparib; assessment for resistance mechanisms and impact of heterogeneity. Circulating tumor DNA measured weekly pre-surgery is assessed for its prognostic value, alone and compared with CA125. The study will enrol 50-70 pts with estimated accrual of 3 pts/month across multiple sites, and opened at Princess Margaret Cancer Centre in 7/2016. Clinical trial information: NCT02489006.

Prevalence and Risk Factors for Presumptive Ascending/Descending Myelomalacia in Dogs after Thoracolumbar Intervertebral Disk Herniation

Background

Ascending/descending myelomalacia (ADMM) is a severe complication of thoracolumbar intervertebral disk herniation (TL‐IVDH) in dogs.

Hypothesis/Objectives

To investigate the prevalence and risk factors for ADMM in nonambulatory dogs with surgically treated TL‐IVDH.

Animals

Six‐hundred and fifty‐two client‐owned dogs evaluated for TL‐IVDH that underwent decompressive spinal surgery.

Methods

Retrospective medical record review from February 2007 through December 2015.

Results

Thirteen dogs developed ADMM, with an overall prevalence of 2.0%. The prevalence of ADMM was 0% in dogs with neurological signs graded 1 or 2 at admission or before magnetic resonance imaging (MRI) or surgical procedures, 0.6% in dogs with neurological signs graded 3, 2.7% in dogs with neurological signs graded 4, and 14.5% in dogs with neurological signs graded 5. Age (<5.8 years), neurological status (grade 5), site of disk herniation (L5‐L6), duration of clinical signs before becoming nonambulatory (<24 hours), detection of intramedullary T2‐weighted (T2W) hyperintensity, and a T2 length ratio >4.57 were significant risk factors in the univariate analysis for development of ADMM.

Conclusions and Clinical Importance

The factors identified in this study may be useful for the prediction of ADMM. Multicenter studies with a higher number of dogs with ADMM are required to confirm these data.

Activation of P2X7 and P2Y11 purinergic receptors inhibits migration and normalizes tumor-derived endothelial cells via cAMP signaling

Purinergic signaling is involved in inflammation and cancer. Extracellular ATP accumulates in tumor interstitium, reaching hundreds micromolar concentrations, but its functional role on tumor vasculature and endothelium is unknown. Here we show that high ATP doses (>20 μM) strongly inhibit migration of endothelial cells from human breast carcinoma (BTEC), but not of normal human microvascular EC. Lower doses (1–10 mm result ineffective. The anti-migratory activity is associated with cytoskeleton remodeling and is significantly prevented by hypoxia. Pharmacological and molecular evidences suggest a major role for P2X7R and P2Y11R in ATP-mediated inhibition of TEC migration: selective activation of these purinergic receptors by BzATP mimics the anti-migratory effect of ATP, which is in turn impaired by their pharmacological or molecular silencing. Downstream pathway includes calcium-dependent Adenilyl Cyclase 10 (AC10) recruitment, cAMP release and EPAC-1 activation. Notably, high ATP enhances TEC-mediated attraction of human pericytes, leading to a decrease of endothelial permeability, a hallmark of vessel normalization. Finally, we provide the first evidence of in vivo P2X7R expression in blood vessels of murine and human breast carcinoma. In conclusion, we have identified a purinergic pathway selectively acting as an antiangiogenic and normalizing signal for human tumor-derived vascular endothelium.

Giant Cell Osteosarcoma in the Calvarium of a Cat

Feline primary osteosarcomas involving the skull are extremely rare. When they occur, orbit, mandible, and maxilla are the most common sites. Microscopically, scattered multinucleated giant cells (MGCs) are not an uncommon occurrence in osteosarcoma (OSC), but they are generally in low number. Only in a rare variant, the giant cell-rich OSC, are MGCs the prevalent cell type. Although osteoclast and osteoblast origin have been postulated in human and veterinary literature, the origin of MGCs in osteosarcomas is poorly understood. This report describes a giant cell-rich OSC in the calvarium of a 13-year-old spayed female shorthair cat. The animal exhibited a range of neurologic signs, including left circling, compulsive gait, lack of proprioception, and bilateral absence of menace reaction, with indication of left forebrain involvement. Gross lesions were characterized by a multilobate, spherical mass located in the left calvarium, compressing the left forebrain. Histologically, the tumor was characterized by scattered nests of MGCs separated by small bundles of pleomorphic, fusate to polygonal cells. Between spindle cells, osteoid was very sparse and arranged in thin strands. immunohistochemical stains for vimentin were positive, with no detectable cellular staining for cytokeratin, S-100 protein, or Class II major histocompatibility complex. Ultrastructurally, MGCs contained profiles of rough endoplasmic reticulum; no lysosomes were observed. The origin of MGCs in osteosarcoma remains obscure, and our results confirm their ambiguous identity.

Abstract PR16: Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy

High-grade serous ovarian carcinoma (HG-SOC) is the most common subtype of ovarian cancer and has the worst prognosis. There is intense controversy on whether the temporal order of cytoreductive surgery and chemotherapy affects treatment outcome, with the main options being primary debulking surgery with adjuvant chemotherapy (PDS) versus neo-adjuvant chemotherapy with interval debulking surgery (NACT). Although some studies report that PDS-treated patients survive significantly longer than those receiving NACT, other reports showed no significant difference patient outcome. To address this question in an unbiased way, we used computational modeling and simulated HG-SOC progression dynamics with different treatments.

We developed a mathematical framework to predict the evolution of chemotherapy resistance, and populated our model with clinical data from nearly 300 patients receiving PDS or NACT from multiple institutes. After estimating the rates of proliferation and mutation of carcinoma cells, we determined that most HG-SOC patients likely harbor chemotherapy-resistant cancer cells at diagnosis. Furthermore, we predicted the effects of PDS and NACT on the number of sensitive and resistant cells, as well as patient survival following treatment, and found that our model closely recapitulated clinical observations in both training and test sets. Based on our results, we predict that PDS with optimal debulking (&lt;1mm residual tumor) has the potential to be curative because surgery can sometimes remove all chemo-resistant cells, while adjuvant chemotherapy depletes the remaining chemo-sensitive cells. By contrast, NACT is unlikely to cure the disease because it depletes chemo-sensitive cells that can mark the location of accompanying “passenger” chemo-resistant cells. Our model also predicts that PDS should have a better outcome than NACT, when controlled for residual tumor size.

Finally, we evaluated the potential benefits of early diagnosis of naive or relapsed HG-SOC. We recapitualted the clinical finding that CA125-based earlier diagnosis of relapsed cancer does not improve survival compared to physical-symptom-based diagnosis. We also predict that more sensitive detection methods (such as ctDNA-based diagnosis) are unlikely to improve survival post-relapse with current chemotherapy, because earlier diagnosis does not decrease the number of chemo-resistant cells, which are already enriched at recurrence. By contrast, our model predicts that with sufficiently sensitive assays, early detection of treatment-naive HG-SOC could improve survival time and increase chance of cure.

This abstract is also presented as Poster B19.

Citation Format: Shengqing Gu, Stephanie Lheureux, Azin Sayad, Liat Hogen Ben-David, Iryna Vyarvelska, Paulina Cybulska, Marcus Bernardini, Barry Rosen, Amit Oza, Benjamin G. Neel. Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr PR16.

Abstract B2-06: Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy

High-grade serous ovarian carcinoma (HG-SOC) is the most common subtype of ovarian cancer and has the worst prognosis. There is intense controversy on whether the temporal order of cytoreductive surgery and chemotherapy affects treatment outcome, with the main options being primary debulking surgery with adjuvant chemotherapy (PDS) versus neo-adjuvant chemotherapy with interval debulking surgery (NACT). Although some studies report that PDS-treated patients survive significantly longer than those receiving NACT, other reports showed no significant difference in patient outcome. To address this question in an unbiased way, we used computational modeling and simulated HG-SOC progression dynamics with different treatments.

We developed a mathematical framework to predict the evolution of chemotherapy resistance, and populated our model with survival data from &gt;300 patients receiving PDS or NACT. After estimating the rates of proliferation and mutation of carcinoma cells, we determined that most HG-SOC patients likely harbor chemotherapy-resistant cancer cells at diagnosis. Furthermore, we predicted the effects of PDS and NACT on the number of sensitive and resistant cells, as well as patient survival following treatment, and found that our model closely recapitulated clinical observations in both training and test sets. Based on our results, we predict that PDS with optimal debulking (&lt;1mm residual tumor) has the potential to be curative because surgery can sometimes remove all chemo-resistant cells, while adjuvant chemotherapy depletes the remaining chemo-sensitive cells. By contrast, NACT is unlikely to cure the disease because it depletes chemo-sensitive cells that can mark the location of accompanying “passenger” chemo-resistant cells. Moreover, NACT results in extensive enrichment of chemo-resistant cells before surgery, but the deposits of such cells are typically too small to be visualized at eventual surgery. Our model also predicts that PDS should have a better outcome than NACT, when controlled for residual tumor size.

Finally, we evaluated the potential benefits of early diagnosis of naïve or relapsed HG-SOC. We recapitulated the clinical finding that CA125-based earlier diagnosis of relapsed cancer does not improve survival. We also predict that more sensitive detection methods (such as ctDNA-based diagnosis) are unlikely to improve survival post-relapse with current chemotherapy, because earlier diagnosis does not decrease the number of chemo-resistant cells, which are already enriched at recurrence. By contrast, our model predicts that with sufficiently sensitive assays, early detection could improve survival time and increase chances of cure.

Citation Format: Shengqing Gu, Stephanie Lheureux, Azin Sayad, Liat Frida Hogen, Iryna Vyarvelska, Paulina Cybulska, Marcus Bernardini, Barry Rosen, Amit Oza, Benjamin G. Neel. Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-06.

Abstract LB-307: Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy

High-grade serous ovarian carcinoma (HG-SOC) is the most common subtype of ovarian cancer and has the worst prognosis. There is intense controversy on whether the temporal order of cytoreductive surgery and chemotherapy affects treatment outcome, with the main options being primary debulking surgery with adjuvant chemotherapy (PDS) versus neo-adjuvant chemotherapy with interval debulking surgery (NACT). Although some studies report that PDS-treated patients survive significantly longer than those receiving NACT, other reports showed no significant difference in patient outcome. To address this question in an unbiased way, we used computational modeling to simulate HG-SOC progression dynamics with different treatments.

We adapted a mathematical framework to predict the evolution of chemotherapy resistance, and populated our model with survival data from &gt;300 patients receiving PDS or NACT. After estimating the mutation rate of carcinoma cells and cancer cell number at diagnosis, we determined that most HG-SOC patients likely harbor chemotherapy-resistant cancer cells at diagnosis. Furthermore, we predicted the effects of PDS and NACT on the number of sensitive and resistant cells, as well as patient survival following treatment, and found that our model closely recapitulated clinical observations in both training and test sets. Based on our results, we predict that PDS with optimal debulking (&lt;1mm residual tumor) has the potential to be curative because surgery can sometimes remove all chemo-resistant cells, while adjuvant chemotherapy depletes the remaining chemo-sensitive cells. By contrast, NACT is unlikely to cure the disease because neo-adjuvant chemotherapy depletes chemo-sensitive cells that can mark the location of accompanying “passenger” chemo-resistant cells. As a result, it leads to extensive enrichment of chemo-resistant cells before surgery, but the deposits of such cells are typically too small to be visualized at eventual surgery. Our model also predicts that PDS should have a better outcome than NACT, when controlled for residual tumor size.

Finally, we evaluated the potential benefits of early diagnosis of naïve or relapsed HG-SOC. We recapitulated the clinical finding that CA125-based earlier diagnosis of relapsed cancer does not improve survival. We also predict that more sensitive detection methods (such as ctDNA-based diagnosis) are unlikely to improve survival post-relapse with current chemotherapy, because earlier diagnosis does not decrease the number of chemo-resistant cells, which are already enriched at recurrence. By contrast, our model predicts that with sufficiently sensitive assays, early detection could improve survival time and increase chances of cure.

Note: This abstract was not presented at the meeting.

Citation Format: Shengqing Gu, Liat Hogen, Stephanie Lheureux, Azin Sayad, Iryna Vyarvelska, Paulina Cybulska, Marcus Bernardini, Barry Rosen, Amit Oza, Benjamin G. Neel. Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-307. doi:10.1158/1538-7445.AM2015-LB-307

Technical update on tissue morcellation during gynaecologic surgery: its uses, complications, and risks of unsuspected malignancy

OBJECTIVE

To review the use of tissue morcellation in minimally invasive gynaecological surgery.

OUTCOMES

Morcellation may be used in gynaecological surgery to allow removal of large uterine specimens, providing women with a minimally invasive surgical option. Adverse oncologic outcomes of tissue morcellation should be mitigated through improved patient selection, preoperative investigations, and novel techniques that minimize tissue dispersion.

EVIDENCE

Published literature was retrieved through searches of PubMed and Medline in the spring of 2014 using appropriate controlled vocabulary (leiomyomsarcoma, uterine neoplasm, uterine myomectomy, hysterectomy) and key words (leiomyoma, endometrial cancer, uterine sarcoma, leiomyosarcoma, morcellation, and MRI). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date limits but results were limited to English or French language materials. Searches were updated on a regular basis and incorporated in the guideline to August 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the report of the Canadian Task Force on Preventive Health Care. (Table 1) BENEFITS, HARMS, AND COSTS: Gynaecologists may offer women minimally invasive surgery and this may involve tissue morcellation and the use of a power morcellator for specimen retrieval. Women should be counselled that in the case of unexpected uterine sarcoma or endometrial cancer, the use of a morcellator is associated with increased risk of tumour dissemination. Appropriate training and safe practices should be in place before offering tissue morcellation. SUMMARY STATEMENTS: 1. Uterine sarcomas may be difficult to diagnose preoperatively. The risk of an unexpected uterine sarcoma following surgery for presumed benign uterine leiomyoma is approximately 1 in 350, and the rate of leiomyosarcoma is 1 in 500. (II-2) This risk increases with age. (II-2) 2. An unexpected uterine sarcoma treated by primary surgery involving tumour disruption, including morcellation of the tumour, has the potential for intra-abdominal tumour-spread and a worse prognosis. (II-2) 3. Uterus-sparing surgery remains a safe option for patients with symptomatic leiomyomas who desire future fertility. (II-1) RECOMMENDATIONS: 1. Techniques for morcellation of a uterine specimen vary, and physicians should consider employing techniques that minimize specimen disruption and intra-abdominal spread. (III-C) 2. Each patient presenting with uterine leiomyoma should be assessed for the possible presence of malignancy, based on her risk factors and preoperative imaging, although the value of these is limited. (III-C) 3. Preoperative endometrial biopsy and cervical assessment to avoid morcellation of potentially detectable malignant and premalignant conditions is recommended. (II-2A) 4. Hereditary cancer syndromes that increase the risk of uterine malignancy should be considered a contraindication to uncontained uterine morcellation. (III-C) 5. Uterine morcellation is contraindicated in women with established or suspected cancer. (II-2A) If there is a high index of suspicion of a uterine sarcoma prior to surgery, patients should be advised to proceed with a total abdominal hysterectomy, bilateral salpingectomy, and possible oophorectomy. (II-2C) A gynaecologic oncology consultation should be obtained. 6. Tissue morcellation techniques require appropriate training and experience. Safe practice initiatives surrounding morcellation technique and the use of equipment should be implemented at the local level. (II-3B) 7. Morcellation is an acceptable option for retrieval of benign uterine specimens and may facilitate a minimally invasive surgical approach, which is associated with decreased perioperative risks. Each patient should be counselled about the possible risks associated with the use of morcellation, including the risks associated with underlying malignancy. (III-C).

The impacts of neoadjuvant chemotherapy and of debulking surgery on survival from advanced ovarian cancer

OBJECTIVES

Women with advanced ovarian cancer are treated with chemotherapy either before (neoadjuvant) or after surgery (primary debulking). The goal is to leave no residual disease post-surgery; for women treated with primary debulking surgery this has been associated with an improvement in survival. It has not been shown that the survival advantage conferred by having no residual disease post-surgery is present for women who receive neoadjuvant chemotherapy.

METHODS

We reviewed the records of 326 women with stage IIIc or IV serous ovarian cancer. We determined if they received neoadjuvant chemotherapy or primary debulking surgery and we measured the extent of residual disease post-surgery. We estimated seven-year survival rates for women after various treatments.

RESULTS

Women who had neoadjuvant chemotherapy were more likely to have no residual disease than women who had primary debulking surgery (50.1% versus 41.5%; p=0.03) but they experienced inferior seven-year survival (8.6% versus 41%; p<0.0001). Among women who had primary debulking surgery, those with no residual disease had much better seven-year survival than women who had any residual disease (73.6% versus 21.0%; p<0.0001). Women who had no residual disease after debulking surgery and who received intraperitoneal chemotherapy had a seven-year survival of 90%.

CONCLUSIONS

Neoadjuvant chemotherapy should be reserved for ovarian cancer patients who are not candidates for primary debulking surgery. Among women with no residual disease after primary debulking surgery, intraperitoneal chemotherapy extends survival.