Arterial stiffness for the early prediction of pre-eclampsia compared with blood pressure, uterine artery Doppler and angiogenic biomarkers: a prospective cohort study

OBJECTIVE

Our aim was to evaluate the ability of arterial stiffness parameters to predict pre-eclampsia early compared with peripheral blood pressure, uterine artery Doppler and established angiogenic biomarkers.

DESIGN

Prospective cohort study.

SETTING

Tertiary care antenatal clinics in Montreal, Canada.

POPULATION

Women with singleton high-risk pregnancies.

METHODS

In the first trimester, arterial stiffness was measured by applanation tonometry, along with peripheral blood pressure and serum/plasma angiogenic biomarkers; uterine artery Doppler was measured in the second trimester. The predictive ability of different metrics was assessed through multivariate logistic regression.

MAIN OUTCOME MEASURES

Arterial stiffness (carotid-femoral pulse wave velocity, carotid-radial pulse wave velocity) and wave reflection (augmentation index, reflected wave start time), peripheral blood pressure, ultrasound indices of velocimetry and circulating angiogenic biomarker concentrations.

RESULTS

In this prospective study, among 191 high-risk pregnant women, 14 (7.3%) developed pre-eclampsia. A first-trimester 1 m/s increase in carotid-femoral pulse wave velocity was associated with 64% increased odds (P < 0.05), and a 1-millisecond increase in time to wave reflection with 11% decreased odds for pre-eclampsia (P < 0.01). The area under the curve of arterial stiffness, blood pressure, ultrasound indices and angiogenic biomarkers was 0.83 (95% confidence interval [CI] 0.74-0.92), 0.71 (95% CI 0.57-0.86), 0.58 (95% CI 0.39-0.77), and 0.64 (95% CI 0.44-0.83), respectively. With a 5% false-positive rate, blood pressure had a sensitivity of 14% for pre-eclampsia and arterial stiffness a sensitivity of 36%.

CONCLUSIONS

Arterial stiffness predicted pre-eclampsia earlier and with greater ability than blood pressure, ultrasound indices or angiogenic biomarkers.

Prognostic biomarkers and clinical outcomes in neuroendocrine prostate cancer (NEPC)

209

Background: NEPC includes both pure small cell carcinoma and mixed tumors with varying degrees of adenocarcinoma and neuroendocrine histology. It arises de novo or is treatment associated (TA) post androgen deprivation therapy. Clinical outcome data and prognostic biomarkers are limited and were thus explored. Methods: Patients with high grade prostate cancer and morphologic and/or immunohistochemical (IHC) NEPC features were included in this retrospective multicentre study. Clinical stage, Gleason score, and serum biomarkers were recorded. Kaplan-Meier method and log-rank test calculated and compared overall survival (OS) from time of NEPC diagnosis.Cox proportional hazards regression assessed prognostic impact of serum biomarkers at diagnosis and de novo vs TA status, adjusting for clinical stage and castration resistance. Results: 135 NEPC cases were identified. 124 (92%) were mixed tumors. 56 (41%) arose de novo. 79 (59%) were TA. 77% of those with a Gleason score (N=85/110) were grade group 5. Median PSA pre-NEPC biopsy was 11.6 ng/mL. At NEPC diagnosis, 19 (14%) had localized disease (median OS 123.0 mo); 33 (24%) non-metastatic castrate-sensitive disease (median OS 42.3 mo); 6 (4%) non-metastatic castrate-resistant disease (median OS 14.3 mo); 35 (26%) metastatic castrate-sensitive disease (median OS 17.6 mo); and 42 (31%) metastatic castrate-resistant disease (median OS 9.6 mo). Median OS for those with visceral metastases was 8.6 mo (95% CI 6.0 – 14.6), compared to patients with non-visceral metastases (11.1 mo; 95% CI 13.7 – 21.5) and no metastases (42.3 mo; 95% CI 47 – 89). Anemia (adjusted HR 1.66; 95% CI 1.05 - 2.16, p = 0.031) and NLR >3 (adjusted HR 1.51; 95% CI 1.01 - 2.52, p = 0.045) were associated with increased risk of death. De novo disease, elevated LDH, serum PSA, and Gleason score were not prognostic. Conclusions: This study identifies NEPC clinical outcomes by stage, with survival poorer than expected in pure prostate adenocarcinoma. Anemia and elevated NLR >3 are prognostic biomarkers that may help risk stratify and guide treatment intensification, including platinum-based chemotherapy. Further biomarker characterization of NEPC through IHC-staining pattern and genomic analysis is currently underway by this group.

Advanced practice physiotherapy care in emergency departments for patients with musculoskeletal disorders: a pragmatic cluster randomized controlled trial and cost analysis

BACKGROUND

Advanced practice physiotherapy (APP) models of care where physiotherapists are primary contact emergency department (ED) providers are promising models of care to improve access, alleviate physicians' burden, and offer efficient centered patient care for patients with minor musculoskeletal disorders (MSKD).

OBJECTIVES

To compare the effectiveness of an advanced practice physiotherapist (APPT)-led model of care with usual ED physician care for persons presenting with a minor MSKD, in terms of patient-related outcomes, health care resources utilization, and health care costs.

METHODS

This trial is a multicenter stepped-wedge cluster randomized controlled trial (RCT) with a cost analysis. Six Canadian EDs (clusters) will be randomized to a treatment sequence where patients will either be managed by an ED APPT or receive usual ED physician care. Seven hundred forty-four adults with a minor MSKD will be recruited. The main outcome measure will be the Brief Pain Inventory Questionnaire. Secondary measures will include validated self-reported disability questionnaires, the EQ-5D-5L, and other health care utilization outcomes such as prescription of imaging tests and medication. Adverse events and re-visits to the ED for the same complaint will also be monitored. Health care costs will be measured from the perspective of the public health care system using time-driven activity-based costing. Outcomes will be collected at inclusion, at ED discharge, and at 4, 12, and 26 weeks following the initial ED visit. Per-protocol and intention-to-treat analyses will be performed using linear mixed models with a random effect for cluster and fixed effect for time.

DISCUSSION

MSKD have a significant impact on health care systems. By providing innovative efficient pathways to access care, APP models of care could help relieve pressure in EDs while providing efficient care for adults with MSKD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05545917 . Registered on September 19, 2022.

Stage migration of testicular germ cell tumours in Alberta, Canada, during the COVID-19 pandemic: a retrospective cohort study

BACKGROUND

An absence of screening recommendations and the rapid progression of testicular germ cell tumours (TGCTs) offer a perspective on the potential impact of the COVID-19 pandemic on cancer presentations. We evaluated the presenting cancer stages of TGCTs in a real-world population before and during the pandemic to assess stage migration.

METHODS

We performed a retrospective review of all new patients with TGCT diagnoses in Alberta, Canada, from Dec. 31, 2018, to Apr. 30, 2021, using the Alberta Cancer Registry. Because potential changes in staging should not occur instantaneously, we used a 6-month lag time from Apr. 1, 2020, for seminomas, and a 3-month lag time for nonseminomas, to compare initial cancer stages at presentation before and during the pandemic. We evaluated monthly rates of presentation by stage and histology. Exploratory outcomes included the largest tumour dimension, tumour markers and, for advanced disease, risk category and treatment setting.

RESULTS

Of 335 patients with TGCTs, 231 were diagnosed before the pandemic and 104 during the pandemic (using a lag time). In total, 18 (7.8%) patients diagnosed before the pandemic presented with stage III disease, compared to 16 (15.4%) diagnosed during the pandemic (relative risk 1.97, 95% confidence interval [CI] 1.05-3.72). We observed no significant differences for secondary outcomes. Without a lag time, the rate ratio for a stage II presentation decreased significantly during the pandemic (0.40, 95% CI 0.21-0.72).

INTERPRETATION

We observed signs of TGCT stage migration during the COVID-19 pandemic, driven by a decline in stage II disease and a potential rise in stage III disease. Management of TGCTs should remain a priority, even during a global pandemic.

Analysis of the role of PI3K-AKT and DNA damage repair (DDR) genomic biomarkers as predictors of clinical outcomes in nonmetastatic castration-resistant prostate cancer (nmCRPC)

175

Background: Clinically relevant outcomes in nmCRPC treated with androgen receptor-axis-targeted therapies (ARAT) may be inferior in patients with tumors harboring mutations bypassing androgen receptor signalling. This final update of a retrospective, multicenter analysis explores the association between genomic mutations in the PI3K-AKT and DDR signalling pathways with ARAT treatment outcomes in nmCRPC patients. Methods: Relevant clinical endpoint were collected for high-risk nmCRPC patients treated with an ARAT at APCaRI affiliated cancer centers, including median metastasis-free survival (MFS), overall survival (OS), PSA decline ≥ 50% (PSA50), and second progression free survival (PFS2). Archival tumor tissue was accessed for next generation gene sequencing, examining for genomic alterations in 500 genes, including those involved in the DDR and the PI3K-AKT signalling pathways. Comparison of outcomes of patients with DDR and PI3K-AKT pathway mutations was conducted using Cox proportional hazards regression using wildtype cases as the reference group, adjusting for PSA doubling time and pelvic lymphadenopathy. Results: Of the 37 patients included, 30 (82%) received apalutamide, 5 (13%) received darolutamide, and 2 (6%) received enzalutamide. 10 patients (27%) had PI3K-AKT pathway mutations (4 PTEN, 3 PIK3Ca, 2 PIK3C2G, 1 PIK3C2b), 8 patients (22%) had DDR gene mutations (3 ATM, 2 CHEK1, 1 BRCA2, 1 CDK12, 1 CHEK2, 1 FANCD2, 1 FANCL), and 1 patient (3%) had 2 MLH1 mutations (microsatellite instability). Of those who had subsequent treatment, 1 received enzalutamide and 5 received abiraterone. Patients with PI3K-AKT pathway mutations had significantly shorter MFS (4.8 mo; HR 4.2; 95% CI 1.2 – 15.0; p = 0.025). Those with DDR mutations had a trend towards shorter MFS (23.3 mo HR 3.7; 95% CI 0.71 – 13.4; p = 0.134). OS data remains immature. 4 (11%) patients did not achieve PSA50, including a patient with 2 MLH1 mutations. Conclusions: This final analysis demonstrates that nmCRPC with PI3K and DDR signalling pathway mutations have poor clinical outcomes when treated with ARAT, likely secondary to decreased reliance on the androgen receptor signalling pathway. These results highlight the potential value of exploring targeted therapies, such as PARP or AKT inhibitors in patients with these mutations.

Association between oncology drug review times and public funding recommendations

99

Background: New oncology drugs undergo detailed review of clinical, economic, and patient data. Thoroughly assessing these data can require lengthy review processes, in the absence of accelerated approval pathways. The aim of this study was to assess how cancer drug review times impact public funding recommendations. Methods: Drugs reviewed by Canada’s health technology assessment body, the pan-Canadian Oncology Drug Review (pCODR), from April 2012 to November 2020 were included in this study. Data was collected including Health Canada approval date, initial and final funding recommendations, treatment intent, drug class, clinical indication (tumour type) and incremental cost-effectiveness ratios (ICER). Univariable and multivariable analyses were used to determine the association between funding recommendations and review times. Results: Of the 227 applications submitted to pCODR, 168 had received positive funding recommendations. Amongst the total drug applications, 24 (14.3%) drugs were intended for the treatment of thoracic cancers, 19 (11.3%) for gastrointestinal cancers, 17 (10.1%) for genitourinary cancers, 17 (10.1%) for breast cancer, and 91 (54.2%) for other tumour sites. Median time from pCODR submission to final recommendation was longer for drugs indicated for the treatment of lung and breast cancer compared to those indicated for treatment of other tumours (223 vs. 212 vs. 203 days, respectively; Kruskal-Wallis p = 0.0322). Drugs with longer review times were more likely to receive a negative pCODR recommendation, even when adjusting for ICER (157 vs 298 days, Wilcoxon p-value = 0.0003). There was no association between positive or negative funding recommendation and tumour type. Conclusions: Oncology drugs with longer review times are less likely to receive recommendation for public funding in Canada. Addressing factors contributing to variance in review times and standardizing the review process can ensure equitable access to cancer drugs.

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39 Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected.

Retrospective cohort analysis of real-world clinical outcomes in nonmetastatic (M0) castration-resistant prostate cancer (CRPC) treated with novel androgen receptor pathway inhibitors (ARPI)

51

Background: The landscape of M0 CRPC has changed with the recent demonstration of metastasis-free survival (MFS) and overall survival (OS) improvements with the use of ARPIs in clinical trial settings. However, the extrapolation of this data to clinical practice is limited by strict exclusion criteria in these trials, including prior or concurrent malignancy, cardiovascular disease, or hypertension. The purpose of this study was to assess real-world outcomes in patients with M0 CRPC treated with ARPIs compared to historical controls. Methods: We designed a retrospective cohort study with the inclusion of patients in Alberta, Canada diagnosed with M0 CRPC between 2001-2020. Via chart review, we identified baseline characteristics, potential confounders, treatment details, and clinical outcomes. The primary outcome of interest was MFS. Secondary outcomes included: second progression-free survival (PFS2) and OS. Median survival times were measured using the Kaplan-Meier method and the log-rank test was used for comparison of outcomes based on ARPI exposure. Cox proportional hazard regression models were used to calculate hazard ratios (HR) accounting for impact of PSA doubling time (PSADT), use of osteoclast inhibiting agents, and presence of pelvic lymphadenopathy. Results: We identified 211 patients across multiple centres in Alberta with M0 CRPC, with 54 having received apalutamide (40/54), enzalutamide (7/54), or darolutamide (7/54). Median age at M0 CRPC diagnosis was 74 years; median PSADT was 4.4 months; and 19% of patients (40/211) had pelvic lymphadenopathy at diagnosis. Median MFS in patients treated with ARPIs was 47.5 months compared to 20.6 months in those not treated with ARPIs (HR, 0.23; 95% confidence interval [CI], 0.11-0.49; p < 0.001). Median PFS2 in ARPI treated patients was 66.3 months compared with 35.6 months (HR, 0.40; 95% CI, 0.18-0.87; p = 0.022). Median OS for patients treated with ARPI was not reached. Conclusions: Given the older age of men with advanced prostate cancer, real-world outcomes that include patients with comorbidities are important adjuncts to the interpretation of clinical trials exploring the benefit of novel therapeutics. Here, we demonstrate that in a real-world, unselected population of men with M0 CRPC, apalutamide, enzalutamide, and darolutamide seem to confer similar MFS and PFS2 benefits to those demonstrated in the SPARTAN, PROSPER, and ARAMIS studies. Real-world OS data remain immature and will be an important addition to these findings.

Sequence decision making for cabazitaxel (Cbz) versus abiraterone (Abt) or enzalutamide (Enz) post-docetaxel (Dtx) in a publicly funded health care system

57

Background: The TROPIC trial demonstrated an overall survival (OS) benefit of Cbz after Dtx in metastatic castrate-resistant prostate cancer (mCRPC). However, the novel anti-androgens (NAA) Abi and Enz have demonstrated similar improvements post-Dtx. The recent CARD trial suggests Cbz may provide the greatest OS benefit in selected patients who were rapid progressors ( < 12 months, RP) on first NAA, however Cbz use and efficacy in the real-world is uncertain. We sought to quantify the real-world use of Cbz and evaluate outcomes post-Dtx. Methods: mCRPC patients who received Dtx at the two tertiary referral centres in the Canadian province of Alberta from October 2012 (Cbz funding approval) to December 31st 2017 were assessed. We examined Cbz eligibility per TROPIC and CARD trial criteria, tracked therapies received, and documented objective and subjective reasoning for therapeutic decisions. OS was measured using the Kaplan-Meier method and the log-rank test was used to compare outcomes. The Chi-Square test was used to compare relative therapy utilization. Results: 463 mCRPC patients received Dtx over the study period, including 83 (18%) for castrate sensitive disease. At Dtx progression, 262 patients (56%) were eligible for Cbz per TROPIC trial criteria, while only 162 (62%) of those were RP on first NAA. Post-Dtx OS was lower among TROPIC-eligible patients receiving Cbz compared to those receiving Abi or Enz (9.1 vs 14.2 months, p = 0.001). This OS difference was not demonstrated among RP patients (11.2 vs 12 months, p = 0.664). The most common reasons for TROPIC ineligibility were Dtx intolerance (13%), serious comorbidities (12%), unacceptable blood counts (11%), performance status (9%) or, for CARD ineligible patients, no progression within 12 months on first NAA (38%). The most common agent immediately post-Dtx was Abi (n = 180, 39%), followed by Enz (n = 129, 28%). Significantly fewer patients (n = 56, 12%) received Cbz immediately post-Dtx (p = 0.001), and 149 (32%) received Cbz overall. First line post-Dtx, 286 patients (62%) did not have a documented discussion about Cbz, and in 172 cases (38%) consideration of Cbz was never documented. Patient choice against Cbz chemotherapy was recorded in 15% of discussions. Conclusions: In a real-world cohort of mCRPC patients, Cbz was a significantly less common choice than Abi or Enz after progression on Dtx. In a majority of these cases, no first line discussion of Cbz was documented, and in documented discussions, patient choice was the driving factor in a minority. OS post-Dtx in patients who met TROPIC trial criteria was lower for those receiving Cbz, noting that, unlike in TROPIC, these patients also received NAAs. This OS difference was not seen in those who also progressed rapidly on first NAA. These data suggest ongoing hesitation towards Cbz use in mCRPC and support careful selection of patients who may obtain benefit.

0682 Evaluation Of An Incentive-based Intervention To Improve 90-day Adherence In Pap-naive Patients

Introduction

Although PAP therapy is the gold standard treatment for obstructive sleep apnea, adherence to treatment is suboptimal. Without sustained therapy adherence, patients are at risk of serious negative health outcomes. The objective of this study was to test whether a digitally delivered monetary and social reward program helped patients new to PAP therapy. Financial incentive schemes are effective in helping patients adhere to difficult medication or therapy plans. Additionally, there is an abundance of evidence that social support is a critical component to long-term health behavior change.

Methods

This prospective, randomized, single site pilot is evaluating the effectiveness of an app-based intervention in helping patients adhere to PAP therapy. The financial incentive design leverages loss aversion, and the social incentive design leverages the strength of close ties and variable reinforcement. The primary endpoint is mean PAP usage at 3 months. Secondary endpoints include Medicare compliance, change in functional status, and baseline scores of perceived disease severity, claustrophobia, coping skills, and health literacy as moderators of the intervention’s effectiveness. Study recruitment is ongoing, with an expected sample size of 150 subjects.

Results

Of the 132 subjects enrolled, 56% are male, 61% are Caucasian, and 65% are married. The mean age is 49.6 ± 12.0 years and mean BMI is 32.4 ± 8.4 kg/m2. Additional demographics such as income level, education level, and number of children along with the primary and secondary endpoints will be presented. A subgroup analysis of the primary endpoint will be generated for subjects identified as strugglers within the first 3 days of usage.

Conclusion

The results of this study will provide insight into methods such as financial and social incentives delivered via a smartphone on initial compliance with PAP therapy, as well as provide more information on the behavioral change associated with beginning PAP therapy.

Support

ResMed

Metastasis-free survival as a predictor of overall survival in non-metastatic castration-resistant prostate cancer

201

Background: Recent trials have shown that apalutamide and enzalutamide can improve metastasis free survival (MFS) in advanced non-metastatic (M0) castrate-resistant prostate cancer (CRPC). MFS is a novel clinical endpoint, demonstrated to be a strong predictor of overall survival (OS) for localized prostate cancer, yet it is unknown if this is also true for M0 CRPC. Our aim was to determine how strongly MFS in M0 CRPC correlates with OS in a real world population. Secondary analyses evaluated whether a rapid PSA-doubling time (PSADT), of ≤10 months, impacts outcomes. Methods: We performed an analysis of patients diagnosed with advanced prostate cancer, followed at the Tom Baker Cancer Centre, in Calgary, Alberta from 2001-2017. Patients were excluded if they did not develop M0 CRPC. MFS and OS were measured using the Kaplan-Meier method and the log-rank test was used to compare outcomes based on PSADT. Correlation between OS and MFS was determined using Pearson Correlation and Kendall’s Tau-B. Results: A total of 1310 patients were identified with advanced prostate cancer, of which 87 developed M0 CRPC. The median age of diagnosis of M0 CRPC was 72 years, with a median Gleason score of 7.0, initial PSA of 10.4, and PSADT of 5.1 months. Only 6 patients were treated with second-generation anti-androgens or chemotherapy. Median MFS and OS after M0 CRPC diagnosis were 44.1 and 83.7 months, respectively. Pearson Correlation between MFS and OS was strong with a coefficient of 0.850 (p < 0.001); with non-parametric Kendall’s Tau, correlation was also strong with a coefficient of 0.632 (p < 0.001). PSADT ≤10 months was identified in 70 patients, and associated with a significantly shorter MFS, compared to a PSADT > 10 months (40.2 vs. 90.4 months; p = 0.001), as well as shorter OS (76.2 vs. 104.3 months; p = 0.008). Conclusions: MFS for M0 CRPC is strongly correlated with OS in a real world population. PSADT of ≤10 months seems to be a useful prognostic tool in estimating MFS and OS in patients with M0 CRPC. MFS was better than expected even in patients with a PSADT of ≤10 months, which may due to our adherence to the biochemical definition of castration-resistant disease, as well as lack of standard imaging intervals in the real world.

First Results from the DEAP-3600 Dark Matter Search with Argon at SNOLAB

This Letter reports the first results of a direct dark matter search with the DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing a large target mass, with the LAr target contained in a spherical acrylic vessel of 3600 kg capacity. The LAr is viewed by an array of PMTs, which would register scintillation light produced by rare nuclear recoil signals induced by dark matter particle scattering. An analysis of 4.44 live days (fiducial exposure of 9.87 ton day) of data taken during the initial filling phase demonstrates the best electronic recoil rejection using pulse-shape discrimination in argon, with leakage <1.2×10^{-7} (90% C.L.) between 15 and 31  keV_{ee}. No candidate signal events are observed, which results in the leading limit on weakly interacting massive particle (WIMP)-nucleon spin-independent cross section on argon, <1.2×10^{-44}  cm^{2} for a 100  GeV/c^{2} WIMP mass (90% C.L.).

Abstract P3-07-08: Quantitative HER family proteins assessment as prognostic and predictive biomarkers in the EGF30008 clinical trial

Background

Combined targeted strategy with letrozole (Le) and lapatinib (La) improves progression-free survival (PFS) in patients with metastatic breast cancer (MBC) co-expressing hormone receptor-positive (HR+) and HER2+ but not in HR+/HER2-negative (HER-) disease (Johnston J Clin Oncol 2009). However, among HER2+ tumors, quantitative levels of HER2 are heterogeneous with a broad dynamic range corresponding to approximately 163.7 to 17446.7 amol/µg as previously reported (Nuciforo SABCS 2014). In addition, within HER2- tumors, quantitative measurement of HER family proteins may identify those patients most likely to benefit from the addition of La to Le. In this retrospective study, we tested the prognostic and predictive ability of HER proteins quantification in clinically HER2+ tumor samples from the EGF30008 study.

Methods

Formalin-fixed paraffin-embedded primary tumor tissues sections from HER2+ MBC population were used. After laser microdissection, tissue lysates were prepared for selected reaction monitoring mass spectrometry (SRM-MS) analysis. Absolute quantitation was accomplished through simultaneous detection of endogenous target and synthetic labeled heavy peptide identical to analytical targets (EGFR, HER2, HER3). HER2 protein levels were correlated with PAM50 molecular subtypes, ERBB2 and ESR1 genes by nCounter. PFS and overall survival (OS) were analyzed by Kaplan–Meier and log-rank test. To determine whether HER2 protein levels were predictive of La benefit, we tested the interaction term of HER2 protein as a continuous variable by treatment arm in a Cox model.

Results

Within the HER2+ study cohort (n=219), 107 had an available tumor block; 84 cases had sufficient material for HER expression measurement by SRM-MS. Average HER2 levels were

2321.1 amol/ug (median, 817.6). HER2 levels were lower in Le+La (n=43; mean, 1761 amol/ug) compared to Le (n=41; mean, 2908 amol/ug) arms, although the difference was non-significant (p=0.108). No expression of EGFR and HER3 was observed. HER2 protein levels were significantly different among PAM50 subtypes with HER2-enriched (HER2E) tumors showing the highest expression followed by Basal-like, Luminal A, Luminal B, and Normal-like (p&lt;0.001). A correlation between HER2 protein, ERBB2 (r=0.5, p&lt;0.001) and ESR1 (r=-0.5, p=0.001) gene expression was found. In patients with disease that expresses HER2 protein levels above the median a trend towards worse PFS (2.9 vs 7.7 months, p=0.092) and OS (21 vs 39 months, p=0.071) were observed. A statistically significant interaction was observed between HER2 protein levels and La treatment for both PFS (p=0.049) and OS (p&lt;0.001). HER2+ tumors with lower expression of HER2 benefited more from La than those with higher expression.

Conclusions

Levels of HER2 protein in HER2+ MBC are extremely heterogeneous. An association between HER2 protein and gene expression by nCounter was observed. HER2E tumors by PAM50 showed the highest levels of HER2 protein. Within the group of HER2+ MBC by standard IHC/FISH, tumors with high HER2 protein had a statistically non-significant worse outcome and do not seem to benefit from La. Further validation of these findings is warranted.

Citation Format: Nuciforo P, Thyparambil S, Galván P, Vilaro M, Jimenez J, Liao W-L, Cecchi F, Blackler A, Press MF, Gagnon R, Ellis C, Hembrough T, Johnston S, Prat A. Quantitative HER family proteins assessment as prognostic and predictive biomarkers in the EGF30008 clinical trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-08.

Abstract P2-08-16: Prognostic and predictive abilities of intrinsic subtype in hormone receptor-positive metastatic breast cancer from the EGF30008 phase III clinical trial

Background

Combination of letrozole and lapatinib improved progression-free survival (PFS) compared with letrozole and placebo in patients with hormone receptor-positive (HR+)/HER2+ metastatic breast cancer (MBC), but not HR+/HER2-negative (HER2-) disease (JCO 2009). However, HR+ disease is clinically and biologically heterogeneous with all intrinsic molecular subtypes (Luminal A, Luminal B, HER2-enriched [HER2E] and Basal-like) identified. Here, we tested retrospectively the prognostic and predictive ability of intrinsic subtype in tumor samples of the EGF30008 trial.

Methods

Expression profiling from FFPE tumor tissues was performed on the nCounter platform. Tumors were classified into each intrinsic subtype using the research-based PAM50 classifier (JCO 2009). Cox proportional hazard models for PFS and overall survival (OS) were used to generate point estimates of hazard ratios (HR) and corresponding 95% confidence intervals (CIs). Changes in likelihood ratio χ2 values were used to measure and compare the relative amount of information of each variable. Variables evaluated were: age, prior endocrine therapy, presence of visceral disease, number of metastatic sites, performance status, clinical HER2 status, and treatment. To determine whether the intrinsic subtypes were predictive of lapatinib benefit, we tested the interaction term of subtype by treatment arm in a Cox model that also included the main effects. Kaplan-Meier plots were used to depict the proportion of patients free from progression as a function of time.

Results

Tumor samples from 821 patients (63.8%) were profiled (85.7% primary and 14.3% metastatic tumor samples). Clinical-pathological features of this patient subset were well balanced compared with the original set. Within the entire cohort, all subtypes were identified: Luminal A (46.5%); Luminal B (29.7%); HER2E (7.4%); Basal-like (3.4%) and normal-like (12.9%). Within HER2+ disease, 28.6% of samples were HER2E. Intrinsic subtype was found the strongest prognostic factor independently associated with PFS and OS in all patients, and in patientswith HER2-negative or HER2+ disease (P&lt;0.0001). Median PFS and OS for each subtype within clinically HER2-negative disease were: Luminal A (16.85 and 45.0 months), Luminal B (10.97 and 37.0 months), HER2E (4.67 and 16.0 months) and Basal-like (4.14 and 23.0 months). Within clinically HER2-negative disease (n=644), 16 patients (2.5%) had HER2E disease. Patients with HER2-/HER2E disease benefited from lapatinib (6.5 vs 2.6 months; PFS HR =0.24, 95% CI: 0.07-0.86; P=0.019; HER2E vs not treatment interaction P=0.016). Finally, intrinsic subtype was not predictive of benefit from lapatinib within HER2+ disease.

Conclusions

HR-positive disease is biologically heterogeneous and intrinsic subtypes are strongly prognostic in a first-line MBC setting. HR+/HER2- disease with a HER2E profile may benefit from lapatinib. The clinical value of intrinsic subtyping in HR+ MBC warrants further investigation, but patients with Luminal A/HER2-negative MBC disease might be good candidates for letrozole monotherapy in the first-line setting regardless of visceral disease and number of metastases.

Citation Format: Prat A, Cheang MCU, Galván P, Nuciforo P, Paré L, Adamo B, Viladot M, Press MF, Gagnon R, Ellis C, Johnston S. Prognostic and predictive abilities of intrinsic subtype in hormone receptor-positive metastatic breast cancer from the EGF30008 phase III clinical trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-16.

A metabolomic study reveals novel plasma lyso-Gb3 analogs as Fabry disease biomarkers

Fabry disease is an X-linked, multisystemic lysosomal storage disorder due to alpha-galactosidase A deficiency. It is characterized by the accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb(3)), in biological fluids, vascular endothelium, heart, and kidneys. Treatment by enzyme replacement therapy has been shown to be beneficial in both males and females affected with the disease. In addition to Gb(3), increased concentrations of globotriaosylsphingosine (lyso-Gb(3)) have recently been reported in urine and plasma of Fabry patients. The overall objective of this metabolomic study was to identify and characterize new potential plasma biomarkers in treated and untreated males and females affected with Fabry disease which might better reflect disease severity and progression. We employed a time-of-flight mass spectrometry metabolomic approach using plasma samples of Fabry patients compared to age-matched controls. We found three new lyso-Gb(3) analogs in Fabry patients presenting m/z ratios at 802, 804, and 820. As previously detected by our group, we also found a m/z ratio of 784 corresponding to the lyso-Gb(3) molecule minus two hydrogen atoms. Using exact mass measurements and tandem mass spectrometry, we confirmed that these analogs result from modifications of the lyso-Gb(3) sphingosine moiety. We evaluated the relative plasma concentration by measuring area counts for each lyso-Gb(3) analog. None of these analogs was detected in the majority of healthy controls. The relative concentration of each analog was higher in males compared to female Fabry patients. We demonstrated that mass spectrometry combined to a metabolomic approach is a powerful tool to detect and identify new potential biomarkers.

Feasibility of vesicoamniotic shunt insertion in an inanimate model: comparison of fetoscopic and ultrasound-guided techniques

OBJECTIVES

To determine the feasibility of fetoscopic vesicoamniotic shunt insertion (F-VASI) in an inanimate model and to compare F-VASI to ultrasound (US)-guided VASI (US-VASI) with respect to accuracy of shunt placement and overall success rate.

METHODS

An inanimate second-trimester fetus with a replaceable bladder balloon was suspended in a pressurized water tank and localized with US. Fetal position was randomized, the operator was blinded and a 5-Fr Harrison Shunt® decompressed the bladder in both groups. Thirty shunt insertions were performed per group.

RESULTS

Procedure time was longer for F-VASI (15.0 vs. 2.8 min, p < 0.05), although it decreased with practice. F-VASI and US-VASI were similar for adequate depth of insertion (27/30 vs. 27/30, p = 1.0), placement within 1 cm of midline (27/30 vs. 25/30, p = 0.42), bladder puncture (28/30 vs. 28/30, p = 1.0), and overall success rate (27/30 vs. 23/30, p = 0.3).

CONCLUSIONS

F-VASI is feasible in an inanimate model. Overall success rate was similar between the groups, although procedure time was longer for F-VASI. Further study is required to determine whether shunt migration is decreased with F-VASI.

Frequency of PIK 3CA Mutations in Chinese HER2+ Metastatic Breast Cancer Patients and Association with Clinical Benefit to Lapatinib and Capecitabine Treatment

Background: Activating mutations in PIK3CA are frequent in breast cancer (Campbell et al. Cancer Res 2004;64:7678-7681). Previous analyses suggest that the presence of PIK3CA activating mutations were associated with poor clinical outcome (Li et al. Breast Can Res Treat 2006;96:91-95) and could confer resistance to treatment with trastuzumab (T) (Berns et al. Cancer Cell 2007;12:395-402). Lapatinib (L) is an oral tyrosine kinase inhibitor targeting EGFR and HER2 pathways. L plus capecitabine (C) has demonstrated efficacy in women with HER2+ metastatic breast cancer (MBC) previously treated with T (Geyer et al. N Engl J Med 2006;355(26):2733-2743). EGF109491 evaluated the efficacy of L+C in 52 Chinese HER2+ MBC patients. The clinical benefit rate (CBR) was 57.7% (PR 44% and SD 44%) and median progression free survival (PFS) was 6.3 months. The purpose of this analysis was to establish the frequency of PIK3CA mutations in this small cohort of Chinese patients and to determine if the presence of a PIK3CA mutation has any impact on clinical benefit to L+C.Methods: 38/52 patients provided tumor samples for biomarker analysis. Briefly, DNA was extracted from these tumor samples, amplified by PCR and sequenced by Pyrosequencing methods to identify the presence of frequent activating mutations in exons 9 and 20 in PIK3CA. Mutation status was tested for association with CBR and PFS using contingency table analysis and proportional hazards analysis respectively.Results:11/38 (29%) patients harbored a mutation in the PIK3CA gene, consistent with published frequencies. 9/11 mutations reside in the catalytic domain and 2/11 mutations reside in the accessory domain of the gene. There was no statistical association with CBR (p=0.639) or PFS (HR=1.01, p=0.989) in PIK3CA wildtype patients vs. PIK3CA mutant patients. PIK3CA wildtype n=27 (%)PIK3CA Mutation n=11 (%)CR0 (0)0 (0)PR12 (44%)4 (36%)SD13 (48%)5 (45%)PD1 (4%)1 (9%)Unknown1 (4%)1 (9%)HR1.01 (p=0.989) Conclusion: The frequency of PIK3CA mutations in this small cohort of Chinese HER2+ MBC patients is consistent with published frequencies. There was no statistically significant association between the presence of a PIK3CA mutation and clinical benefit to L+C in these patients. These results are in agreement with previous reports that mutations in PIK3CA do not seem to impact clinical outcome following L-containing treatment regimens.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1140.

Biomarker Profiles in Trastuzumab (T) Refractory HER2+ Inflammatory Breast Cancer (IBC) That Predict for Survival Benefit from Lapatinib (L) Monotherapy

Background:L is a reversible, oral small molecule inhibitor of EGFR and HER2. L demonstrated an objective response rate (ORR) of 39%, a median progression free survival (PFS) of 14.6 weeks and a median overall survival (OS) of 11.2 months in a monotherapy Phase II study of 126 patients (pts) with HER2+ IBC (Kaufman et al. Lancet Oncology, 2009). In the initial cohort of pts we reported an association between response to L and coexpression of pHER3 with pHER2 (Johnston et al, J Clin Oncol, 2008 26; 1066-72). In this study we measured a series of biomarkers in tumor biopsies obtained before the start of treatment and evaluated their association with parameters of clinical benefit to L in relation to prior T.Methods:Core needle biopsies were obtained pretreatment, preserved in phosphatase inhibitor buffer, fixed in formalin and embedded in paraffin. Baseline expression of total and activated EGFR, HER2, HER3 and downstream markers, as well as markers specific to IBC were determined by standard IHC techniques yielding manual and optical density (OD) scores. 94/126 pts received prior T treatment before beginning L treatment, while 32 patients were T naive. The baseline expression of each marker was tested for association with ORR, PFS and OS using proportional hazards and logistic regression models.Results:OD IHC data indicated pEGFR and TGFα had statistically significant association with OS and PFS in pts treated with prior T. pHER3 also appeared to be associated with OS, although was not statistically significant. Higher levels of these biomarkers were associated with decreased hazard of progression or death. Correlation between OD and manual scores (0,1,2,3) were highly significant for these markers (R=0.80, p&lt;0.0001). These markers were not significant when tested against ORR.[table 1] OSPFSORRpEGFR (N=56)P&lt;0.0001, HR=0.45P=0.0192,HR=0.66P=0.2721,OR=1.44pHER3 (N=71)P=0.0634, HR=0.74P=0.1256, HR=0.78P=0.0920, OR=1.72TGFα (N=57)P=0.0019, HR=0.95P=0.0386, HR=0.97P=0.8211, OR=1.05HR; Hazard Ratio, OR; Odds Ratio (odds of response)When we evaluated the same panel of biomarkers in T naïve pts, higher levels of HER2 expression were significantly associated with improved ORR (p=0.0186) and a trend towards significance with OS (p=0.0674). Furthermore, higher levels of pAKT (p=0.0068) and pERK (p=0.006) were significantly associated with improved OS.Discussion:L monotherapy is clinically active in the treatment of relapsed/refractory HER2+ IBC. Higher levels of pEGFR and TGFa by IHC are significantly associated with improved OS and PFS but not ORR in patients with prior T therapy. In contrast, T naïve pts, higher levels of pAKT and pERK showed a significant association with OS. Thus, different biomarker profiles may predict benefit in T naïve vs T-refractory pts benefiting from L monotherapy in HER2+ IBC.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 706.

Clinical benefit of lapatinib-based therapy in patients with HER2-positive breast tumors expressing p95HER2

1048

Background: Approximately 25% of HER2 overexpressing breast tumors express a truncated form of the receptor (p95HER2) that lacks the extracellular domain but retains kinase activity. p95HER2-positive tumors are associated with a worse prognosis and resistant to trastuzumab therapy. In preclinical models, lapatinib (L), a tyrosine kinase inhibitor of EGFR and HER2, is active in p95HER2 expressing tumors. The aim of this analysis was to test the hypothesis that benefit from L-based therapy is independent of p95HER2 expression in 2 clinical trials in patients (pts) with HER2-positive tumors treated with either L monotherapy (Study EGF20009 ) or L in combination with capecitabine (Study EGF100151). Methods: Pre-treatment tumor tissue from both trials (N=201) was analyzed for p95HER2 expression by immunofluorescence as previously described (Scaltriti M. et al, JNCI 2007). Expression of p95HER2 was correlated with clinical benefit rate (CBR: complete response [CR] + partial response [PR] + stable disease [SD] ≥ 24 weeks) and progression-free survival (PFS) using logistic regression and Cox-proportional hazard models. Results: 68/105 and an initial 72/96 tissue samples were evaluable for p95HER2 expression from studies EGF20009 and EGF100151, respectively. The Table summarizes the results from the L treated pts. The CBR and PFS in L treated pts were not significantly different between the p95HER2 subgroups. Expanded data for p95HER2 expression in additional EGF100151 tumor samples will be presented. Conclusions: L as a monotherapy or in combination with capecitabine has similar response activity in pts with p95HER2-positive and p95HER2-negative HER2-positive breast tumors.

[Table: see text]

[Table: see text]

Relevance of serum HER2 extracellular domain (sECD) in EGF30008, a study of letrozole ± lapatinib in patients (pts) with hormone-receptor positive (HR+) metastatic breast cancer (MBC)

1019

Background: Elevated baseline sECD (BsECD) correlates weakly with HER2 overexpression (HER2+). HR+ MBC. Lapatinib benefit was reported in pts with HER2+ tumors irrespective of BsECD status; BsECD status did not predict benefit for HER2- negative (HER2-ve) tumors. sECD levels and their predictive and prognostic value for progression-free survival (PFS) were further examined in a randomized, phase III trial of letrozole ± lapatinib. Methods: Pts (n=1286) with HR+ MBC were randomized to letrozole with placebo (P) or lapatinib (L). HER2 status was evaluated by FISH or IHC in archived tissue. sECD was measured by ELISA at baseline (n=1102 available samples), and every 4 wk. Pts were considered sECD+ if serum sECD was >15 ng/ml. Results: BsECD was positive in 14% (125/894) and 42% (87/208) of pts with HER2-ve and HER2+ tumors, respectively. Correlation between BsECD and FISH was weak but significant in HER2+ pts (R=0.35, p<0.0001) but not in HER2-ve pts (R=0.03, p=0.362). Unlike for HER2+ tumors, BsECD+ did not predict benefit in PFS from L in pts with HER2-ve tumors. HR: Hazard Ratio In pts with HER2- ve tumors, median ECD levels were stable in the P arm but increased slightly (4 ng/mL) in the L arm. In the HER2+ group, median levels in the P arm declined (3.5 ng/mL) but increased at 4 wk in L arm (3.4 ng/mL) and were stable thereafter. Conversion from sECD-ve to sECD+ was observed in both arms but did not correlate with outcome or provide predictive value. Data related to ECD status conversion will be reported. Conclusions: BsECD+ status correlates with HER2+ tumor status and may predict L benefit but BsECD+ status did not predict benefit in pts with HER2-ve tumors. On therapy changes in median sECD were small. Conversion from BsECD-ve to sECD+ did not predict L benefit and we could not confirm that evaluation of on treatment ECD status may help treatment decision.

[Table: see text]

[Table: see text]

Relationship between total and high molecular weight adiponectin levels and plasma nonesterified fatty acid tolerance during enhanced intravascular triacylglycerol lipolysis in men

CONTEXT

Increased plasma nonesterified fatty acid (NEFA) appearance during enhanced intravascular triacylglycerol (TG) lipolysis is a marker of metabolic adipose tissue dysfunction and may lead to the development of insulin resistance. The relationship between total and high molecular weight (HMW) adiponectin levels, NEFA appearance, and total TG lipolytic capacity has not been previously studied in humans.

OBJECTIVES

Our objective was to determine whether total and HMW adiponectin plasma levels are associated with plasma NEFA level and appearance, and with total TG lipolytic rate during enhanced intravascular TG lipolysis in men.

DESIGN

This was a cross-sectional metabolic study.

SETTING

The study was performed at an academic clinical research center.

PARTICIPANTS

There were 15 healthy men (mean +/- sd body mass index 25.5 +/- 4.7 kg/m(2)) aged 21-50 yr (mean +/- sd 31.1 +/- 10.2) without first-degree relatives with type 2 diabetes included in the study.

INTERVENTIONS

Pancreatic clamps and iv infusion of stable isotopic tracers ([1,1,2,3,3-(2)H(5)]glycerol and [U-(13)C]palmitate) were performed, whereas intravascular TG lipolysis was clamped by iv infusion of heparin plus Intralipid at low (fasting) and high insulin levels. Total and HMW adiponectin levels were measured using an ELISA.

MAIN OUTCOME MEASURES

Levels of total and HMW adiponectin, palmitate appearance (plasma palmitate appearance rate), and glycerol appearance (plasma glycerol appearance rate) were calculated.

RESULTS

During heparin plus Intralipid infusion, total and HMW adiponectin was inversely correlated with plasma palmitate appearance rate (r = -0.65; P = 0.01), but this association was lost when expressed per nonlean weight. Adiponectin levels were positively associated with plasma glycerol appearance rate per nonlean weight (r = 0.71 and r = 0.66, respectively; P < or = 0.01).

CONCLUSIONS

Increased adipose tissue mass likely explains the association between low adiponectin and reduced NEFA tolerance. Adiponectin level is a marker of total TG lipolytic rate per adipose tissue mass in men.

A 6 gene molecular predictor of lapatinib related benefit: from cell line models to clinical trials

Abstract #58

Background: Identification of molecular predictors of response is an important aspect of individualized cancer treatment. Responses to lapatinib (L), an oral inhibitor of HER2 and EGFR, approved in combination with capecitabine for HER2+ metastatic breast cancer (MBC), were evaluated in a panel of BC cell lines. Computational approaches were used to identify transcripts that quantitatively associate with response to L in the cell line panel that were then tested in 2 clinical trials.&#x2028; Methods: The clinical utility of a 6-gene predictor was tested retrospectively using a branched-chain DNA assay in paraffin-embedded archival tumor tissue from patients (pts) with HER2 negative or untested MBC tumors enrolled in a phase III trial of paclitaxel (P) vs. P+L, and from pts with HER2 positive MBC enrolled in a L monotherapy trial. Expression of HER2 transcript using the branched-chain assay was compared with HER2 fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) status; discordant cases were analyzed. Response patterns for pts with HER2+ tumors and a computational model that predicts L sensitivity or resistance is described.&#x2028; Results: Ingenuity analysis of the mRNA predictors of response to L identified in the BC cell line panel revealed saturated gene networks with HER2 as a major node. The 6-gene predictor of response was comprised of 2 genes associated with sensitivity to L: HER2 and GRB7; 4 genes associated with resistance to L: CRK, ACOT9, FLJ31079, and DDX5. Expression results for the 6 genes and progression-free survival (PFS) data were available for 159 pts on L+P. Median PFS in the branched-chain HER2+ group was 32.9 wks vs. 22.4 wks in the HER2-negative group. The 6-gene predictor was used to predict response to L in the HER2+ pts. Comparison of PFS in the 24 “L sensitive” tumors vs. 25 “L resistant” tumors indicated that the predictor, derived from cell-line analyses, had the potential to predict clinical response to L in pts treated with L+P (HR=0.58; 95% CI=0.30-1.11; p=0.07). The 6-gene predictor was further tested in an independent L monotherapy study in pts with HER2 FISH+ MBC. Comparison of PFS in the 24 “L sensitive” tumors vs. 28 “ L resistant” tumors reconfirmed the potential of the 6-gene predictor to enrich for HER2+ pts most likely to experience clinical benefit from L (HR=0.40; 95% CI=0.19-0.84; p=0.015). Further testing is ongoing.&#x2028; Conclusions: This study suggests that molecular predictors of clinical response can be developed through an analysis of response from a collection of 50 BC cell lines. The identification of a L specific 6-gene assay is promising as a clinical predictor of benefit from L in pts with HER2+ BC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 58.

Province-wide population survey of acute appendicitis in Canada. New twists to an old disease

BACKGROUND

This study, sponsored and conducted by Le Collège des Médecins du Québec, audited the management of acute appendicitis in the Province of Québec (Population 7.6 million), Canada, over a period of 1 year (April 2002-March 2003).

METHODS

A questionnaire was sent to the Health Records Department of all hospitals surgically treating appendicitis in the province. Data from 85 (100%) hospitals were received and reviewed.

RESULTS

During the study period, 7,599 appendectomies were performed, and 5,707 (75%) were selected for study (55% men). The rate of normal and perforated appendix was 5.4% and 15.9% respectively. Median hospital stay for simple and perforated appendicitis was 2.6 and 5.8 days, respectively. At least one imaging procedure was done in 86% of cases (23% computed tomography [CT], 55% ultrasound). Antibiotics were not given in 7% of cases and in 8% of patients with a perforation. Seventeen percent of patients did not receive preoperative or intraoperative doses, and postoperatively, 69% of patients received unnecessary doses. Laparoscopy was used in 35% of cases and was associated with a reduction in postoperative stay for simple (2.6 versus 2.9 days, p < 0.001) and perforated appendicitis (4.6 versus 5.9 days, p = 0.004). A low rate of laparoscopy (<25%) was found in 53% of teaching (University and Affiliated) and 45% of nonteaching institutions. Conversion to open surgery was necessary in 9.7% of simple appendicitis and 29.3% of perforated ones (p < 0.001).

CONCLUSIONS

Although results of this survey are comparable to those of similar published series, a few concerns emerge. Many have to do with patient noncompliance with recommended antibiotic usage for acute appendicitis. Further, although laparoscopy seems to be slowly making its way into the surgical armamentarium, the low rate of laparoscopic appendectomies in teaching hospitals raises the issue of appropriate resident training.

Initial development of an integrated optoelectronic probe for biomedical imaging

There has recently been increased interest and progress in the development of medical diagnostic techniques based on the optical properties of tissues (e.g. optical absorption and scattering at different wavelengths) and various substances of interest (e.g. fluorescence of intra-cellular structures, drugs, or dyes). Many applications could be envisaged for an optical probe or imaging system that is both inexpensive and small enough to be portable or even implantable. However, current systems do not meet these two criteria, as they are generally constructed using discrete components. We present an integrated circuit implementation of an optical probe, where a detector and receiver circuit are fabricated together on a single chip in a standard analog CMOS process. The advantages of an integrated probe, as opposed to a more conventional optical fiber-based approach, include improvements in light collection efficiency, signal to noise ratio, size, and cost.

Assessment in the context of uncertainty: how many members are needed on the panel of reference of a script concordance test?

PURPOSE

The script concordance test (SCT) assesses clinical reasoning in the context of uncertainty. Because there is no single correct answer, scoring is based on a comparison of answers provided by examinees with those provided by members of a panel of reference made up of experienced practitioners. This study aims to determine how many members are needed on the panel to obtain reliable scores to compare against the scores of examinees.

METHODS

A group of 80 residents were tested on 73 items (Cronbach's alpha: 0.76). A total of 38 family doctors made up the pool of experienced practitioners, from which 1000 random panels of reference of increasing sizes (5, 10, 15, 20, 25 and 30) were generated with a resampling procedure. Residents' scores were computed for each panel sample. Units of analysis were means of residents' score, test reliability coefficient and correlation coefficient between scores obtained with a given panel of reference versus the scores obtained with the full panel of 38. Statistics were averaged across the 1000 samples for each panel size for the mean and test reliability computations, and across 100 samples for the correlation computation.

RESULTS

For sample variability, there was a 3-fold increase in standard deviation of means between a sample panel size of 5 (SD=1.57) and a panel size of 30 (SD=0.50). For reliability, there was a large difference in precision between a panel size of 5 (0.62) and a panel size of 10 (0.70). When the panel size was over 20, the gain became negligible (0.74 for 20 and 0.76 for 38). For correlation, the mean correlation coefficient values were 0.90 with 5 panel members, 0.95 with 10 members and 0.98 with 20 members.

CONCLUSION

Any number over 10 is associated with acceptable reliability and good correlation between the samples versus the full panel of 38. For high stake examinations, using a panel of 20 members is recommended. Recruiting more than 20 panel members shows only a marginal benefit in terms of psychometric properties.

Peak Effect and the Phase Diagram of Moving Vortices in FexNi1-xZr2 Superconducting Glasses

In the mixed state of type II superconductors, vortices penetrate the sample and form a correlated system due to the screening of supercurrents around them. Interestingly, we can study this correlated system as a function of density and driving force. The density, for instance, is controlled by the magnetic field B, whereas a current density j acts as a driving force F=j x B on all vortices. To minimize the pinning strength, we study a superconducting glass in which the depinning current is 10 to 1000 times smaller than in previous studies, which enables us to map out the complete phase diagram in this new regime. The diagram is obtained as a function of B, driving current, and temperature, and leads to a remarkable set of new results, which includes a huge peak effect, an additional reentrant depinning phase, and a driving force induced pinning phase.