Development and validation of a questionnaire to assess knowledge in patients with Atrial Fibrillation

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Centre for Heart Rhythm Disorders

Background

Education is critical to empower individuals to self-monitor and manage their condition. Significant variability exists in the provision of education for atrial fibrillation (AF), whilst individual patient factors including health literacy and education level attainment may impact on knowledge levels. Objective assessment of knowledge  may help to target education to areas of need, and result in improved patient outcomes.

Objective

To describe the development and validation of a knowledge questionnaire for AF.

Methods

A multidisciplinary expert team of healthcare professionals developed the questionnaire, in conjunction with consumers, with question content based upon areas deemed most critical to AF and related self-management. The multiple choice questionnaire consists of 20 items, each worth 5 points, to give a total score out of 100. The questionnaire assesses five domains specific to AF: general knowledge, complications, medications, risk factors and action. The questionnaire was developed in English. The questionnaire was tested on 10 randomly selected patients with AF for face validity and 19 healthcare professionals for content validity. The final version was completed by 454 individuals with AF. Exploratory factor analysis was used to determine construct validity with factor loadings of 0.40 and above considered acceptable. Reliability was assessed using Cronbach’s alpha, with a value greater than 0.7 acceptable.

Results

Face and content validity were considered acceptable, after minor changes to wording. The cohort of 454 individuals with AF had a mean age of 66.9 ± 12 years and 43% were female. Mean (SD) total score was 57.7 ± 15.8. Exploratory factor analysis was undertaken using the principal components method. This resulted in a Kaiser–Meyer–Olkin Measure of Sampling Adequacy of .64 and a Bartlett"s Test of Sphericity being significant at 0.00. Seven factors were selected and analysed using principal component analysis with varimax rotation. All items loaded on one of the seven factors. Internal consistency demonstrated a Cronbach’s alpha of 0.65.

Conclusion

The Atrial Fibrillation Knowledge Questionnaire is a valid measure to assess knowledge in individuals with AF.

Cardiorespiratory fitness and electroanatomical remodelling in patients with atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Atrial fibrillation (AF) is the most common clinically-relevant arrhythmia. Its initiation and maintenance is linked to the presence cardiovascular risk factors such as hypertension and obesity. Higher cardiorespiratory fitness (CRF) has been associated with a better prognosis. However, specific electroanatomical features associated with baseline CRF have not been described. 

Purpose

Compare electroanatomical substrate across exercise capacity levels in patients with AF

Methods

Patients referred for de novo AF radiofrequency ablation at the Centre for Heart Rhythm Disorders from August 2017 until June 2020 were screened for inclusion and CRF was evaluated in metabolic equivalents (METs) by a symptom-limited maximal treadmill exercise test using the standard Bruce protocol prior to ablation. Predicted CRF was calculated based on established equations and patients were categorized according to the percentage of predicted CRF achieved; low (<85%), adequate (85-100%) and high (>100%). Total mean and regional peak-to-peak bipolar voltages, percent of low voltage areas (% LVA), conduction velocity (CV) and percent of complex fractionated electrograms (% CFE) in sinus rhythm were compared across groups. 

Results

There were no between-group differences in baseline characteristics, medication use or echocardiographic features. Total mean voltage was significantly lower in the low CRF group compared to both adequate and high CRF. Compared to the high CRF group, roof (3.25 ± 1.2 mV vs 1.9 ± 1.3 mV, p < 0.05), posterior (3.8 ± 1.8 mV vs 1.7 ± 0.9 mV, p < 0.001) and inferior mean voltages (3.4 ± 2 mV vs 1.6 ± 0.7 mV, p < 0.05) were significantly lower in the low CRF group (figure 1A). Furthermore, compared with the adequate CRF group, mean voltages were significantly lower in the posterior (3.7 ± 1.5 mV vs 1.7 ± 0.9 mV, p < 0.001), inferior (3.4 ± 1 mV vs 1.6 ± 0.7 mV, p < 0.001) and lateral (4.2 ± 2.2 mV vs 2.1 ± 1.4 mV, p < 0.05) walls of the low CRF group. Anterior and septal mean voltages were not significantly different across CRF groups (P for trend = 0.07, 0.3 and 0.15, respectively). Conduction velocities were not significantly different across groups. The inferior %LVA was significantly higher in the low CRF (5.6 ± 6%) compared to adequate CRF group (23 ± 18%) (p < 0.05) (figure 1B). Total and regional % CFE was higher in the low CRF compared to adequate and high CRF.

Conclusion

Participants in the lower baseline CRF category showed significant reductions in regional voltages along with higher fractionation with preserved conduction velocities. Research on the effect of physical activity and CRF on left atrial arrhythmogenic substrate is required.

Abstract Figure. Global and regional mV and % LVA by CRF

70Autonomic dysfunction in atrial fibrillation (AF) patients: absent vasomotor reflex to decreased cardiac venous return during af in comparison to sinus rhythm; implications for earlier rhythm control

Funding Acknowledgements

Dr Malik is supported by an Australian Postgraduate Award Scholarship from the University of Adelaide.

OnBehalf

Centre for Heart Rhythm Disorders, University of Adelaide & Royal Adelaide Hospital

Background

A bi-directional relationship exists between AF and the autonomic nervous system (ANS). Patients with AF studied in sinus rhythm (SR) have impaired vasomotor responses to decreased cardiac volume. Whether autonomic dysfunction worsens during AF itself, is unknown. 

Purpose

We examined haemodynamic responses to lower body negative pressure (LBNP) in patients with persistent AF compared to AF studied in SR. LBNP decreases cardiac volume, deactivates atrial stretch receptors and induces a reflex to maintain blood pressure by increasing systemic vascular resistance (SVR). 

Methods

21 consecutive patients with paroxysmal or persistent AF were studied; during AF (n = 8) or SR (n = 13). Anti-arrhythmic and anti-hypertensives were withheld for 5 half-lives. Patients underwent LBNP using a custom-made chamber sealing both lower limbs. Negative pressure at sham (-0 mmHg), low (-20 mmHg) and high level (-40 mmHg) was applied for 5 minutes each. Finger photo plethysmography was used for beat-beat-blood pressure. Computation of SVR during AF is not feasible with this method. Therefore, the right forearm was used to perform venous occlusion plethysmography (VOP); non-invasive, well validated with LBNP and impervious to AF: to estimate forearm blood flow (FBF) and SVR (inversely proportional). 

Results

Baseline characteristics and responses to LBNP are presented in Table 1. MAP was maintained, and HR rose slightly, in the SR group. MAP and HR decreased in the AF group. VOP demonstrates a reduction in FBF in the SR group (vasoconstriction); whereas the vasomotor response to LBNP was absent during AF. Figure 1 (Panels A-C). 

Conclusion

The presence of AF is associated with autonomic dysfunction from impaired cardiac volume regulation. This novel finding may contribute to the known risk of falls and syncope due to AF. Further studies are needed to evaluate whether abnormal cardiac reflexes are involved in atrial remodelling and AF progression.

Table 1 Baseline Characteristics During AF During SR P Value Age 65 ± 5 59 ± 3 0.4 AAD & Anti-HTN medications withheld (%) 75 85 0.6 Resting mean arterial pressure (MAP) 109 ± 9 93 ± 6 0.1 Resting heart rate (HR) 94 ± 6 60 ± 4 0.0001* Haemodynamic response to LBNP % Δ MAP due to LBNP -9 ± 5 +0.5 ± 3 0.2 % Δ HR due to LBNP -6 ± 3 +5 ± 3 0.03* % Δ FBF due to LBNP +75 ± 59 -27 ± 8 0.02* AAD Anti-arrhthmic. HTN: Hypertension. Mean +/- SEM.

Abstract Figure. Vasomotor response to LBNP: in AF vs SR

P5657Fibrosis detected by late-gadolinium enhancement cardiac MRI is associated with atrial fibrillation and poorer ablation outcome: A meta-analysis

Background

Fibrosis is a hallmark of atrial fibrillation (AF) substrate. Recent data suggests that fibrosis detected by late-gadolinium enhancement (LGE) cardiac MRI (CMR) can predict AF. However, this relationship is not well described.

Objective

To delineate the association of cardiac fibrosis detected by LGE CMR with AF prevalence, AF recurrence after catheter ablation.

Methods

PubMed, Embase, Web of Science and Ovid MEDLINE were searched through November 2018, using the keywords: LGE AND Fibrosis AND CMR AND AF. Inclusion criteria: 1. LGE CMR of left atrial (LA LGE), ventricular wall (LV LGE) or right ventricular wall (RV LGE); 2. Studies reporting AF or recurrent arrhythmia after ablation; 3. Patient ≥18 years; and 4. ≥50 participants. Included studies were pooled in a random effects meta-analysis and reported as: mean difference (MD); unadjusted risk ratios (RR); adjusted hazard ratios (HR); and 95% confidence intervals (95% CI).

Results

After exclusions, we identified 9 studies (2,307 patients [65.9% males, 34.1% females]) conducted between 2003 and 2015 for LGE and AF. Fibrosis was present in 666 (35.1%) and detected by LV LGE in 7 (78%) and RV LGE in 2 (22%). The presence of AF was higher in patients positive for ventricular LGE than those negative, trending towards significance (RR: 1.51, 95% CI: 0.94–2.45, p=0.09). Pooled LV fibrosis associated with AF progression (RR [NPAF vs. PAF]: 2.2, 95% CI: 1.22–3.94, p=0.009). We identified 8 studies (2,041 patients [65.8% males, 34.2% females]) conducted between 2006 and 2016 reporting LGE and AF recurrence after catheter ablation, with fibrosis detected in 644 (31.6%) by LA LGE in 8 (88.9%, biased towards one centre). After 17.8±14.2 follow-up years, atrial fibrosis was significantly greater in recurrent AF than controls (MD: 4.97%, 95% CI: 1.23–8.7, p<0.01), and predicted 16% increased risk of AF recurrence (RR: 1.16, 95% CI: 1.07–1.26, p<0.05).

Conclusion

Myocardial fibrosis detected by LGE associates with prevalence and progress of AF and is predictive of AF recurrence post ablation. This further supports the proarrhythmic role of fibrosis and selection of patients for ablation therapy based on LGE.

P1234Weight fluctuation demonstrates residual atrial arrhythmogenic substrate despite final weight loss in a chronic sheep model: implications for epicardial fat and fibrofatty infiltrates

Background

Obesity-mediated epicardial adipose tissue (EAT) expansion drives fat cell infiltration which forms the unique substrate for atrial fibrillation (AF). The LEGACY study showed the benefits of weight loss but an attenuated response with weight fluctuation. How fluxes in weight impacts the atrial substrate in not known.

Objective

To investigate EAT and the atrial substrates due to weight fluctuation, with comparison to stable obesity.

Methods

We studied 24 sheep in 3 equal groups over 80 weeks: 1. Obesity induced by high calorie diet fed ad libitum; 2. Weight fluctuation induced by 20-week cycle of weight gain/loss (20:20:20:20); and 3. Lean controls fed quality hay to maintain baseline weight. All sheep underwent: daily weight measurement; haemodynamic and imaging assessments (cardiac MRI; dual-energy X-ray absorptiometry; and matrix assisted laser desorption infrared lipid imaging); electrophysiological studies and electroanatomic mapping; histological and structural analysis. Evaluations included: atrial voltage, conduction velocity, and refractoriness (7 sites, 2 cycle lengths), electrogram fractionation, EAT volume, fibro-fatty infiltration, myolysis of myocytes, and spatial distribution of intra-atrial lipids.

Results

The Table shows the group differences. Compared to reference controls, obesity demonstrated: Increased atrial volume and pressure, abnormal atrial electrical properties, expanded EAT and ensuing fibro-fatty infiltrations, and myolysis of myocytes. Despite comparable weight and EAT with controls, weight fluctuation resulted in extensive and severe fibro-fatty infiltrations, and twofold greater myolysis that persisted. Moreover, characteristic profiles and abundance of lipid species in the atrial myocardium were noted on further evaluation. More importantly, EAT and fibro-fatty infiltrates strongly correlated with increased atrial volume and pressure; with only fibro-fatty infiltrates correlating with fractionated electrograms (r=0.71, p<0.001) and conduction slowing (r=−0.59, p=0.006). Similarly, atrial myolysis exhibited significant correlations with atrial enlargement and haemodynamics, and electrical substrates (p<0.05 for all).

Conclusions

Obesity induces fibro-fatty replacement of atrial myocytes and deterioration of contractile units, which may drive impaired electrical remodeling. Despite final weight loss, weight fluctuation demonstrates residual electro-structural, fibro-fatty and contractile substrates.

P6294NLRP3 inflammasome is activated in the atrium of an ovine model of sustained obesity

Introduction

Obesity and enhanced inflammatory response are two independent risk factors involved in the pathogenesis of atrial fibrillation (AF). Components of the NLRP3 inflammasome have been found to be expressed in cardiomyocytes and cardiac fibroblasts and that increased inflammasome activation contributes to the pathogenesis of AF. The NLRP3 inflammasome is a multi-protein signaling complex that is activated in two steps: 1st) a priming event that includes a NFκB-activating stimuli which increases the expression of pro-inflammatory cytokines, and 2nd) a triggering event that includes the assembly of the inflammasome complex and activation of caspase-1 which promotes the production of pro-inflammatory cytokines like interleukin 1 beta (IL-1b).

Purpose

We used a sheep model of sustained obesity to characterize the association between atrial myocardial fat infiltration, atrial activation of the NLRP3 inflammasome and the development of an atrial arrhythmogenic substrate for AF.

Methods

Eight sheep were fed ad libitum calorie-dense diet over 40 weeks to gain weight and were maintained in this state of sustained obesity for another 40 weeks. Eight lean, weight-controlled and aged-matched sheep served as control. Atrial fat infiltration was determined by oil-red staining and NLRP3 inflammasome activation was assessed by immunoblot in atrial whole-tissue lysate. Atrial effective refractory periods (aERPs) were evaluated (twice diastolic threshold, cycle length (CL) of 400 ms, S1S2 -protocol).

Results

Sustained obesity was associated with increased atrial fat infiltration (lean: 0.8±0.3% vs. obese: 2.3±1.2%, p=0.1) and shorter aERP (lean: 169±22ms vs. obese: 138±26ms, p=0.03). Protein levels of caspase-1 and mature IL-1β were significantly enhanced (p=0.04 and p=0.01, respectively). Further shortening of aERP correlated with increasing atrial protein levels of caspase-1 (r=0.59, p=0.02). In contrast, levels of TNFα and NFκB were not significantly changed in atria of sheep with sustained obesity.

Conclusions

Sustained obesity is associated with increased expression of NLRP3 inflammasome-related proteins and the development of an arrhythmogenic substrate for AF. Our study suggest that the increased activity is due to increased triggering, rather than increased gene transcription. Whether NLRP3 inflammasome activation represents a modifiable target to prevent AF in obesity warrants further study.

Phase I study of the halichondrin B analogue eribulin mesylate in combination with cisplatin in advanced solid tumors

BACKGROUND

Eribulin mesylate is a synthetic macrocyclic ketone analogue of Halichondrin B that has demonstrated high antitumor activity in preclinical and clinical settings. This phase I study aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics in combination with cisplatin (CP) in patients with advanced solid tumours.

METHODS

Thirty-six patients with advanced solid tumours received eribulin mesylate 0.7-1.4 mg m(-2) and CP 60-75 mg m(-2). Eribulin mesylate was administered on days 1, 8, and 15 in combination with CP day 1 every 28-day cycle. The protocol was amended after dose level 4 (eribulin mesylate 1.4 mg m(-2), CP 60 mg m(-2)) when it was not feasible to administer eribulin mesylate on day 15 because of neutropenia; the treatment schedule was changed to eribulin mesylate on days 1 and 8 and CP on day 1 every 21 days.

RESULTS

On the 28-day schedule, three patients had DLT during the first cycle: grade (G) 4 febrile neutropenia (1.0 mg m(-2), 60 mg m(-2)); G 3 anorexia/fatigue/hypokalemia (1.2 mg m(-2), 60 mg m(-2)); and G 3 stomatitis/nausea/vomiting/fatigue (1.4 mg m(-2), 60 mg m(-2)). On the 21-day schedule, three patients had DLT during the first cycle: G 3 hypokalemia/hyponatremia (1.4 mg m(-2), 60 mg m(-2)); G 4 mucositis (1.4 mg m(-2), 60 mg m(-2)); and G 3 hypokalemia (1.2 mg m(-2), 75 mg m(-2)). The MTD and recommended phase II dose was determined as eribulin mesylate 1.2 mg m(-2) (days 1, 8) and CP 75 mg m(-2) (day 1), on a 21-day cycle. Two patients had unconfirmed partial responses (PR) (pancreatic and breast cancers) and two had PR (oesophageal and bladder cancers).

CONCLUSIONS

On the 21-day cycle, eribulin mesylate 1.2 mg m(-2), administered on days 1 and 8, in combination with CP 75 mg m(-2), administered on day 1 is well tolerated and showed preliminary anticancer activity.

Automated quantification of atrial fibrillation complexity by probabilistic electrogram analysis and fibrillation wave reconstruction

The analysis of high-density activation maps of atrial fibrillation (AF) provides fundamental insights into the fibrillation wave propagation patterns and thus the mechanisms of AF. Current annotation of local activations in unipolar atrial electrograms and the construction of fibrillation waves require labor-intensive manual editing. To enhance the possibilities for spatiotemporal analysis of AF, we developed a rapid and fully automated procedure to accurately identify local, intrinsic atrial deflections and construct fibrillation waves based on these deflections. In this study, the automated procedure was validated using manually annotated electrograms and wave maps. We show that the novel procedure accurately detects intrinsic deflections (sensitivity=87%, positive predictive value=89%) and that reconstructed wave maps correlate well with manually edited wave maps in terms of number of waves (r=0.96), intra-wave conduction velocity (r=0.97), AF cycle length (r=0.97), and wave size (r=0.96) (p&#60;0.01 in all cases). The automated procedure is therefore an adequate substitute for manual annotation.

Evidence-based management of heart failure in clinical practice: a review of device-based therapy use

BACKGROUND

Heart failure is a growing health issue and is associated with significant mortality risk. Device therapy is efficacious in preventing sudden death in patients with heart failure; however, this evidence comes from rigorous clinical trials. It is unclear how device therapy is utilized in 'real-world' practice. The primary objective was to characterize patterns of device use in patients with heart failure at risk of sudden death and to identify barriers to guideline-driven prescription of implantable cardioverter-defibrillators.

METHODS

We report a cross-sectional study of patients attending general cardiology clinic over a 3-month period.

RESULTS

Of 1003 consecutive patients attending the cardiology clinic, 176 had heart failure. Of these, 66 were potentially eligible for device therapy, but only 16 of these had actually undergone device implantation. Potentially eligible non-recipients were older (P < 0.001), more likely to have ischaemic cardiomyopathy (P= 0.002), less likely to be prescribed spironolactone (P= 0.005) or warfarin (P= 0.02), and less likely to have a widened QRS > 120 ms (P= 0.005). There was a high prevalence of underuse of evidence-based pharmacotherapies among patients with heart failure.

CONCLUSION

There is substantial underuse of device therapy in patients with heart failure. Strikingly, whereas patients with symptoms of heart failure were more likely to receive a device, those being managed for ischaemic heart disease were not. There is also a high prevalence of failure to prescribe evidence-based pharmacotherapy in a tertiary hospital general cardiology clinic. This may be explained in part by the lack of a patient database to record treatment contraindications and to alert clinicians to possible gaps in patient therapy.

Triple-negative breast cancer in Hong Kong Chinese patients

e22127

Background: There is increasing data showing that breast cancer is a heterogeneous disease which should be assessed separately in different populations, as it differs substantially between Chinese and Caucasian women. Triple-negative breast tumours which are negative for ER, PR and HER-2 neu receptors are associated with younger age at presentation, tumour of higher grade with larger size and a poorer prognosis. There is recent suggestion that the prognostic outlook of Chinese triple-negative breast cancers might be somewhat different from those in the Western population, but few studies have attempted to understand the role of ethnic factor in the triple-negative entity. Methods: We conducted a preliminary retrospective comparison of 170 Hong Kong Chinese primary breast cancer patients seen as new cases during January 2004 and December 2004 in a teaching hospital. Clinico-pathological features of triple-negative tumours were compared to their non-triple-negative counterpart. Results: Triple negative breast cancer accounted for 12.4% of all breast cancer patients seen in the year of 2004 (n = 21). It is associated with more cancers with grade 3 tumour (68.4% vs 36.8%; p = 0.02) but there was no statistically difference between the age of presentation, tumour size, extensive intraductal component, lymph node status and rate of local relapse or metastasis after adjuvant therapy. Subset analysis further revealed that when triple negative breast cancer patients (n = 21) were compared to the HER-2 positive patients (n = 40) in the studied population, HER-2 positive patients were still associated with higher proportion of node positive disease (57.5% vs 30.0%; p = 0.04). Disease free survival and overall survival were not studied due to limited follow-up time. Conclusions: Our preliminary findings suggested that Hong Kong Chinese triple-negative breast cancers are associated with a more favourable outlook and might behave differently when compared to their Western counterpart. Further large-scale study of the ethnic factor with long-term follow-up is warranted.

No significant financial relationships to disclose.

Dual epidermal growth factor receptor (EGFR) inhibition: Phase I study combining cetuximab (C225) and erlotinib (E) in advanced solid tumors

3552

Background: The EGFR pathway is implicated in lung tumorigenesis by aberrantly regulating cell proliferation, apoptosis, and invasion. Maximal blockade of the EGFR can be achieved by dually inhibiting the extracellular and intracellular domain with the monoclonal antibody C225 and the tyrosine kinase inhibitor, E. Given preclinical synergy of C225 and E, we hypothesized this combination would be feasible and result in improved therapeutic benefit. Methods: Patients (pts) with advanced solid tumors were enrolled using a standard phase I dose escalation design. C225 was administered IV weekly, with no loading dose, and E given orally daily on a 28-day cycle. Four dose levels were studied: C225 150 mg/m2, E 100 mg; C225 200 mg/m2, E 100 mg; C225 250 mg/m2, E 100 mg; and C225 250 mg/m2, E 150 mg. Dose limiting toxicity (DLT) was defined as: grade (Gr) 4 platelets, Gr 3 platelets with bleeding, febrile neutropenia, ≥ Gr 3 ANC with documented infection, or clinically significant > Gr 3 non-hematologic toxicity. Gr 3 rash based solely on pain or Gr 3 hypersensitivity infusion reactions were not considered DLTs. Results: 18 pts were treated: 13 NSCLC, 3 H&N, 1 pancreas, and 1 invasive thymoma. Characteristics: Age range 41–80, median 62.5; Gender: 7 M; ECOG PS ≤1 = 17; Prior chemo ≤1 = 10. Planned dose escalation was completed without reaching the MTD. The highest dose level was expanded to 6 pts. A single DLT for Gr 3 diarrhea was observed at the second dose level (C225 200 mg/m2, E 100 mg). Gr 3/4 toxicities were: lymphopenia (3), acneiform rash (3), nausea/vomiting (3), pruritis (1), fatigue (1), diarrhea (1), confusion (1), hypomagnesemia (1), hypocalcemia (1), hyponatremia (1), hyperkalemia (1), and anemia (1). Of 13 evaluable pts, 1 PR (NSCLC) and 4 with SD (2 NSCLC, 2 H&N). Median cycles: 2 (1–14) with one NSCLC pt on therapy for 8 cycles and one H&N pt receiving 14 cycles. Biomarker analysis of EGFR polymorphisms, gene copy number via FISH, and protein expression will be presented, along with the mutation status of EGFR and KRAS. Conclusions: 1) Dual EGFR inhibition with C225 250 mg/m2 weekly and E 150 mg daily is feasible, well tolerated, and the recommended phase II dose. 2) Efficacy of this combination in NSCLC is being evaluated in a phase II trial.

[Table: see text]

Integration of new chemotherapeutic agents into chemoradiotherapy for stage III non--small cell lung cancer: focus on docetaxel

Randomized clinical trials have shown that combinations of chemotherapy plus thoracic radiation improve survival compared with radiotherapy alone in stage III non--small cell lung cancer (NSCLC). Furthermore, two recent studies have concluded that concurrent chemoradiotherapy produces superior results to sequential administration. Dependent on the dose and schedule used, chemotherapy may contribute by eradicating distant micrometastases by improving local control as a radiosensitizer, or through both mechanisms. In general, sequential approaches in which full-dose platinum-based chemotherapy precedes thoracic radiation or surgery have improved outcome by impacting distant metastases. In contrast, concurrent chemoradiotherapy using low-dose cisplatin is reported to improve survival by reducing local recurrence without an impact on distant failure rates. In view of these observations, chemoradiotherapy strategies integrating both radiosensitizing agents and dose levels of chemotherapy effective against micrometastases may prove to be most efficacious. Because distant metastases remain the major site of failure, it also is likely that more effective chemotherapy will be required to further improve the current level of response and survival. Fortunately, several newly available chemotherapeutic agents are both highly active against NSCLC and are potent radiosensitizers. In this report we review recent data regarding integration of new chemotherapeutic agents into chemoradiotherapy programs in stage III NSCLC, focusing on trials investigating docetaxel. Encouraging results, including those of the Southwest Oncology Group trial 9504, suggest that docetaxel will play a major role in the future of combined-modality therapy for locally advanced NSCLC. Semin Oncol 28 (suppl 9):26-32.

Activity of high-dose toremifene plus cisplatin in platinum-treated non-small-cell lung cancer: a phase II California Cancer Consortium Trial

PURPOSE

Although cisplatin is an important agent in non-small-cell lung cancer (NSCLC), de novo resistance is common and acquired resistance emerges rapidly during therapy. Proposed mediators of platinum resistance include the protein kinase C (PKC) signal transduction pathway and associated c-FOS overexpression. While estrogen administration has been reported to upregulate PKC and c-FOS expression, the triphenylethylenes tamoxifen and toremifene potentiate platinum cytotoxicity by inhibition of PKC. Downregulation of c-FOS expression has been reported to result from PKC inhibition. In view of these findings, we hypothesized that toremifene would reverse platinum resistance and that this interaction would be influenced by tumor estrogen receptor (ER) status.

MATERIALS AND METHODS

A phase II trial of high-dose toremifene (600 mg orally daily on days 1-7) plus cisplatin (50 mg/m2 intravenously on days 4 and 11) every 28 days in NSCLC patients was conducted. A group of 30 patients with metastatic NSCLC who had been previously treated with platinum-based therapy were enrolled.

RESULTS

All of the 30 patients were assessable for toxicity and 28 for tumor response. Therapy was well tolerated with minimal hematologic and non-hematologic toxicity. Common toxicity criteria grade 3 hematologic toxicity was seen in only three patients. Five patients achieved a partial response for an overall response rate of 18% (95% CI 6-37). Median overall survival was 8.1 months (95% CI 5.4-17). To assess PKC, ER, and c-Fos expression by immunohistochemistry, 12 informative pretreatment patient tumor specimens were obtained. Four patient tumor specimens were positive for one or both PKC isoforms (alpha and epsilon) while c-Fos was overexpressed in three. None of the responding patient tumors exhibited c-FOS or PKC-epsilon overexpression. ER expression was found to be infrequent (8%), contrasting with previous reports in this tumor type.

CONCLUSION

While this phase II study indicates that high-dose toremifene plus cisplatin is feasible, active, and well tolerated in NSCLC patients previously treated with platinum compounds, the mechanism of action remains unclear. Further study of this regimen is warranted.

Sequential combination chemotherapy in patients with advanced nonsmall cell lung carcinoma: carboplatin and gemcitabine followed by paclitaxel

BACKGROUND

The objective of this Phase II study was to evaluate the concept of sequential chemotherapy in the treatment of patients with advanced nonsmall cell lung carcinoma (NSCLC) by the administration of carboplatin plus gemcitabine followed by of paclitaxel.

METHODS

Patients with Stage IIIB (pleural effusion) or Stage IV NSCLC and a Southwest Oncology Group (SWOG) performance status (PS) of 0--2 were eligible. Therapy consisted of three cycles of carboplatin (area under the concentration-time curve = 5.5 mg/mL per minute) on Day 1 and gemcitabine 1000 mg/m(2) on Days 1 and 8 every 21 days followed by three cycles of paclitaxel 225 mg/m(2) every 21 days.

RESULTS

Of the 37 eligible patients, 81% had Stage IV disease, and 27% had a PS of 2; all were assessable for survival and toxicity; 32 patients were assessable for response. After treatment with carboplatin plus gemcitabine, there were no complete responses (CRs) and eight partial responses (PRs) (response rate [RR], 25%; 95% confidence interval [95% CI], 11--43%). The best overall response was two CRs and eight PRs (RR, 31%; 95% CI, 16--50%). The median survival time was 9.5 months, the 1-year survival rate was 36% (95% CI, 26--44%), the 2-year survival rate was 11% (95% CI, 3--25%), and the median time to disease progression was 4.9 months. The median survivals were 11.2 months for patients with a PS of 0--1 and 6.4 months for patients with a PS of 2. Noncumulative, reversible thrombocytopenia was the principal toxicity with carboplatin/gemcitabine therapy. Paclitaxel therapy was well tolerated, and moderate (Grade 3) neutropenia was the primary toxic effect. One cardiac death occurred, possibly related to paclitaxel.

CONCLUSIONS

This study is the first to evaluate planned sequential chemotherapy in patients with NSCLC. Carboplatin plus gemcitabine followed by paclitaxel was well tolerated and resulted in promising survival in this patient population. This pilot experience forms the basis for an ongoing SWOG trial. Cancer 2001;92:146-52. Published 2001 American Cancer Society.

KT3.2 and KT3.3, two novel human two-pore K(+) channels closely related to TASK-1

We report the cloning of human KT3.2 and KT3.3 new members of the two-pore K(+) channel (KT) family. Based on amino acid sequence and phylogenetic analysis, KT3.2, KT3.3, and TASK-1 constitute a subfamily within the KT channel mammalian family. When Xenopus oocytes were injected with KT3.2 cRNA, the resting membrane potential was brought close to the potassium equilibrium potential. At low extracellular K(+) concentrations, two-electrode voltage-clamp recordings revealed the expression of predominantly outward currents. With high extracellular K(+) (98 mM), the current-voltage relationship exhibited weak outward rectification. Measurement of reversal potentials at different [K(+)](o) revealed a slope of 48 mV per 10-fold change in K(+) concentration as expected for a K(+)-selective channel. Unlike TASK-1, which is highly sensitive to changes of pH in the physiological range, KT3.2 currents were relatively insensitive to changes in intracellular or extracellular pH within this range due to a shift in the pH dependency of KT3.2 of 1 pH unit in the acidic direction. On the other hand, the phorbol ester phorbol 12-myristate 13-acetate (PMA), which does not affect TASK-1, produces strong inhibition of KT3.2 currents. Human KT3.2 mRNA expression was most prevalent in the cerebellum. In rat, KT3.2 is exclusively expressed in the brain, but it has a wide distribution within this organ. High levels of expression were found in the cerebellum, medulla, and thalamic nuclei. The hippocampus has a nonhomogeneous distribution, expressing at highest levels in the lateral posterior and inferior portions. Medium expression levels were found in neocortex. The KT3.2 gene is located at chromosome 8q24 1-3, and the KT3.3 gene maps to chromosome 20q13.1.

Integration of new chemotherapeutic agents into chemoradiotherapy for stage III non--small cell lung cancer: focus on docetaxel

Randomized clinical trials have shown that combinations of chemotherapy plus thoracic radiation improve survival compared with radiotherapy alone in stage III non--small cell lung cancer (NSCLC). Furthermore, two recent studies have concluded that concurrent chemoradiotherapy produces superior results to sequential administration. Dependent on the dose and schedule used, chemotherapy may contribute by eradicating distant micrometastases by improving local control as a radiosensitizer, or through both mechanisms. In general, sequential approaches in which full-dose platinum-based chemotherapy precedes thoracic radiation or surgery have improved outcome by impacting distant metastases. In contrast, concurrent chemoradiotherapy using low-dose cisplatin is reported to improve survival by reducing local recurrence without an impact on distant failure rates. In view of these observations, chemoradiotherapy strategies integrating both radiosensitizing agents and dose levels of chemotherapy effective against micrometastases may prove to be most efficacious. Because distant metastases remain the major site of failure, it also is likely that more effective chemotherapy will be required to further improve the current level of response and survival. Fortunately, several newly available chemotherapeutic agents are both highly active against NSCLC and are potent radiosensitizers. In this report we review recent data regarding integration of new chemotherapeutic agents into chemoradiotherapy programs in stage III NSCLC, focusing on trials investigating docetaxel. Encouraging results, including those of the Southwest Oncology Group trial 9504, suggest that docetaxel will play a major role in the future of combined-modality therapy for locally advanced NSCLC. Semin Oncol 28 (suppl 9):26-32.

Prospective evaluation of cancer clinical trial accrual patterns: identifying potential barriers to enrollment

PURPOSE

Well-conducted cancer clinical trials are essential for improving patient outcomes. Unfortunately, only 3% of new cancer patients participate in clinical trials. Barriers to patient accrual in cancer clinical trials must be identified and overcome to increase patient participation.

MATERIALS AND METHODS

We prospectively tracked factors that potentially affected patient accrual into cancer clinical trials at the University of California Davis Cancer Center. Oncologists seeing new outpatients were asked to complete questionnaires regarding patient characteristics and the physician's decision-making on patient eligibility, protocol availability, and patient opinions on participation. Statistical analysis was performed to correlate these parameters with subsequent protocol accrual.

RESULTS

There were 276 assessable patients. At the initial visits, physicians did not consider clinical trials in 38% (105/276) of patients principally because of a perception of protocol unavailability and poor performance status. Physicians considered 62% (171/276) of patients for participation in clinical trials. Of these, only 53% (91/171) had an appropriate protocol available for site and stage of disease. Seventy-six of 90 patients (84%) with available protocols met eligibility criteria for a particular study. Only 39 of 76 patients (51%) agreed to participate in cancer clinical trials, for an overall accrual rate of 14% (39/276). The remainder (37/76, 49%) declined trial participation despite meeting eligibility criteria. The most common reasons were a desire for other treatment (34%), distance from the cancer center (13%), patient refusal to disclose reason (11%), and insurance denial (8%). Patients with private insurance were less likely to enroll in clinical trials compared to those with government-funded insurance (OR, 0.34; P =.03; 95% CI, 0.13 to 0.9).

CONCLUSION

Barriers to cancer clinical trial accrual can be prospectively identified and addressed in the development and conduct of future studies, which may potentially lead to more robust clinical trials enrollment. Investigation of patient perceptions regarding the clinical trials process and the role of third party-payers is warranted.

Gemcitabine in combination with new platinum compounds: an update

Combinations of gemcitabine (Gemzar) with cisplatin (Platinol) are among the most active new chemotherapy regimens developed for advanced non-small-cell lung cancer. Carboplatin (Paraplatin) is a platinum analog devoid of many of the nonhematologic toxicities associated with cisplatin. Although few direct comparisons have been made, when administered by area under the concentration-time curve (AUC) dosing, carboplatin is probably equivalent to cisplatin in advanced non-small-cell lung cancer and provides an improved therapeutic index. Based on its favorable toxicity profile, carboplatin has supplanted cisplatin for use in combination with paclitaxel in several different tumor types. Initial trials combining gemcitabine and carboplatin using standard days 1, 8, and 15 dosing of gemcitabine suggested that thrombocytopenia was problematic. More recently, 21-day schedules in which gemcitabine is administered only on days 1 and 8 have demonstrated both efficacy and improved toxicity profiles. Here we review recent studies investigating gemcitabine plus carboplatin and preliminary data regarding combinations of gemcitabine with the new platinum analog oxaliplatin.

Neoadjuvant therapy for non-small cell lung cancer

Clinical trials evaluating neoadjuvant or preoperative therapy for locally advanced non-small cell lung cancer (NSCLC) have demonstrated the feasibility, tolerability and activity of this approach. Three randomized trials have reported improved survival in patients with stage III NSCLC treated with preoperative chemotherapy followed by surgical resection compared to surgery alone. Combinations of neoadjuvant chemotherapy plus thoracic radiotherapy have also been investigated, generally resulting in higher rates of pathologic response, but higher toxicity rates as well. The best approach to neoadjuvant therapy remains to be determined and may well be substage dependent. In bulky stage III NSCLC, the role of surgery itself remains unclear and is the subject of an ongoing intergroup trial in the US. Regardless, neoadjuvant therapy has emerged as an important paradigm for clinical research since it serves as an in vivo test of chemosensitivity in patients, and represents a 'window of opportunity' for testing new chemotherapeutic agents and novel strategies. Among the new chemotherapeutic agents being investigated in this setting is docetaxel, one of the most active agents in first- and second-line chemotherapy of NSCLC, and a potent radiosensitizer. Preliminary studies have confirmed the feasibility of integrating docetaxel into neoadjuvant treatment strategies and encouraging results have been reported.

Gemcitabine/carboplatin combination regimens: importance of dose schedule

Platinum compounds, either cisplatin (Platinol) or carboplatin (Paraplatin), in combination with a number of new chemotherapeutic agents, have demonstrated improved response or survival compared to cisplatin alone or older platinum-based regimens. Gemcitabine (Gemzar)-platinum combinations are of particular interest because of their interactive mechanisms of action, demonstrated preclinical synergism, and the single-agent activity of gemcitabine. Indeed, gemcitabine and cisplatin regimens have proven to be among the most efficacious in the palliative treatment of advanced non-small-cell lung cancer. In view of the reduced nonhematologic toxicities associated with the platinum analogue, carboplatin, several combinations of new agents and carboplatin have been developed and incorporated into clinical practice. This article describes recent clinical trials evaluating gemcitabine plus carboplatin, and the impact of the dosing schedule on the feasibility and tolerability of this combination.

Treatment of poor-prognosis extensive disease small-cell lung cancer with an all-oral regimen of etoposide and cyclophosphamide - a Southwest Oncology Group clinical and pharmacokinetic study

PURPOSE

An all-oral regimen of etoposide and cyclophosphamide was developed for use in poor-prognosis extensive disease small-cell lung cancer. Limited pharmacokinetic sampling was used to derive a pharmacodynamic model predictive of myelosuppression early in the course of therapy.

PATIENTS AND METHODS

Eligible patients were chemotherapy-naive and had extensive disease small-cell lung cancer with either SWOG performance status 2 or serum albumin <3.5 g/dl. The first cohort (n = 18) received etoposide orally at 50 mg daily and cyclophosphamide orally at 50 mg daily days 1-14 every 28 days. Due to good hematologic tolerance, the second cohort (n = 39) received both agents orally at 50 mg twice daily days 1-14 every 28 days. Plasma etoposide levels were determined in samples drawn at baseline, and at 1 h, 2 h, and 23.5 h (trough) after the first dose. Linear regression analysis was used to determine pharmacokinetic and demographic parameters predictive of myelosuppression.

RESULTS

A total of 173 treatment cycles were delivered. Patients on the daily regimen had a 22% response rate (complete and partial), a 22% unconfirmed response rate, and a 5-month median survival, while patients on the twice-daily regimen had a 28% response rate (complete and partial), a 13% unconfirmed response rate, and a 7-month median survival. Granulocytopenia and alopecia were the most common toxicities seen. Significant granulocytopenia could be predicted for the twice-daily regimen according to the formula ln(AGC nadir)=7.80 - 1.88(trough), with an increased incidence of granulocytopenia if the etoposide trough value was >/=1.49 microg/ml.

CONCLUSION

Oral etoposide and oral cyclophosphamide given days 1-14 every 28 days is well tolerated and results in an acceptable response rate and median survival in poor-prognosis (poor performance status or low serum albumin) extensive disease small-cell lung cancer. A trough etoposide level obtained within 24 h of starting therapy can predict severe granulocytopenia.

Paclitaxel (Taxol): an inhibitor of angiogenesis in a highly vascularized transgenic breast cancer

Paclitaxel (Taxol), a promoter of microtubule polymerization and a radiosensitizing agent, is one of the more active anticancer drugs in the current treatment of solid tumors. In this study, we show that paclitaxel possesses an antiangiogenic property associated with a down-regulation of vascular endothelial growth factor (VEGF) in a highly-vascularized transgenic murine breast cancer (Met-1). Paclitaxel, at non-cytotoxic doses of 0, 3 and 6 mg/kg/day, was administered intraperitoneally for 5 days to nude mice bearing the Met-1 breast tumor. Extent of intratumoral angiogenesis, as indicated by microvessel tortuosity and microvessel density, was significantly reduced by paclitaxel in a dose-dependent manner. Paclitaxel also suppressed expression of VEGF in the Met-1 cells transplanted in nude mice or maintained in cell culture. These results indicate that antiangiogenesis associated with a down-regulation of VEGF is an additional mode of action of paclitaxel.

Severe esophageal toxicity after thoracic radiation therapy for lung cancer associated with the human immunodeficiency virus: a case report and review of the literature

This case report documents severe esophagitis and rapid esophageal stricture formation in a man infected with the human immunodeficiency virus (HIV) who was treated with standard thoracic irradiation for locally advanced non-small-cell lung cancer. Severe late esophageal toxicity is a rare complication of radiation therapy in patients who are HIV negative, but those who are HIV positive may be at increased risk. This article reviews the literature suggesting that HIV infection may lead to unusually severe radiation-induced mucosal injury. High-dose chest irradiation should be performed with caution in this group of patients.