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Dive into the research topics where Klaus Richter Larsen is active.

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Featured researches published by Klaus Richter Larsen.


The New England Journal of Medicine | 2009

Preoperative Staging of Lung Cancer with Combined PET–CT

Barbara M. Fischer; Ulrik Lassen; Jann Mortensen; Søren S. Larsen; Annika Loft; Anne K Bertelsen; Jesper Ravn; Paul Clementsen; Asbjørn Høgholm; Klaus Richter Larsen; Torben Riis Rasmussen; Susanne Keiding; Asger Dirksen; Oke Gerke; Birgit Guldhammer Skov; Ida Steffensen; Hanne Sand Hansen; Peter Vilmann; Grete Krag Jacobsen; Vibeke Backer; Niels Maltbaek; Jesper Holst Pedersen; Henrik Madsen; Henrik Nielsen; Liselotte Højgaard

BACKGROUND Fast and accurate staging is essential for choosing treatment for non-small-cell lung cancer (NSCLC). The purpose of this randomized study was to evaluate the clinical effect of combined positron-emission tomography and computed tomography (PET-CT) on preoperative staging of NSCLC. METHODS We randomly assigned patients who were referred for preoperative staging of NSCLC to either conventional staging plus PET-CT or conventional staging alone. Patients were followed until death or for at least 12 months. The primary end point was the number of futile thoracotomies, defined as any one of the following: a thoracotomy with the finding of pathologically confirmed mediastinal lymph-node involvement (stage IIIA [N2]), stage IIIB or stage IV disease, or a benign lung lesion; an exploratory thoracotomy; or a thoracotomy in a patient who had recurrent disease or death from any cause within 1 year after randomization. RESULTS From January 2002 through February 2007, we randomly assigned 98 patients to the PET-CT group and 91 to the conventional-staging group. Mediastinoscopy was performed in 94% of the patients. After PET-CT, 38 patients were classified as having inoperable NSCLC, and after conventional staging, 18 patients were classified thus. Sixty patients in the PET-CT group and 73 in the conventional-staging group underwent thoracotomy (P=0.004). Among these thoracotomies, 21 in the PET-CT group and 38 in the conventional-staging group were futile (P=0.05). The number of justified thoracotomies and survival were similar in the two groups. CONCLUSIONS The use of PET-CT for preoperative staging of NSCLC reduced both the total number of thoracotomies and the number of futile thoracotomies but did not affect overall mortality. (ClinicalTrials.gov number, NCT00867412.)


Thorax | 2012

CT screening for lung cancer brings forward early disease. The randomised Danish Lung Cancer Screening Trial: status after five annual screening rounds with low-dose CT

Zaigham Saghir; Asger Dirksen; Haseem Ashraf; Karen Skjøldstrup Bach; John Brodersen; Paul Clementsen; Martin Døssing; Hanne Sand Hansen; Klaus F. Kofoed; Klaus Richter Larsen; Jann Mortensen; Jakob F. Rasmussen; Niels Seersholm; Birgit Guldhammer Skov; Hanne Thorsen; Philip Tønnesen; Jesper Holst Pedersen

Background The effects of low-dose CT screening on disease stage shift, mortality and overdiagnosis are unclear. Lung cancer findings and mortality rates are reported at the end of screening in the Danish Lung Cancer Screening Trial. Methods 4104 men and women, healthy heavy smokers/former smokers were randomised to five annual low-dose CT screenings or no screening. Two experienced chest radiologists read all CT scans and registered the location, size and morphology of nodules. Nodules between 5 and 15 mm without benign characteristics were rescanned after 3 months. Growing nodules (>25% volume increase and/or volume doubling time<400 days) and nodules >15 mm were referred for diagnostic workup. In the control group, lung cancers were diagnosed and treated outside the study by the usual clinical practice. Results Participation rates were high in both groups (screening: 95.5%; control: 93.0%; p<0.001). Lung cancer detection rate was 0.83% at baseline and mean annual detection rate was 0.67% at incidence rounds (p=0.535). More lung cancers were diagnosed in the screening group (69 vs 24, p<0.001), and more were low stage (48 vs 21 stage I–IIB non-small cell lung cancer (NSCLC) and limited stage small cell lung cancer (SCLC), p=0.002), whereas frequencies of high-stage lung cancer were the same (21 vs 16 stage IIIA–IV NSCLC and extensive stage SCLC, p=0.509). At the end of screening, 61 patients died in the screening group and 42 in the control group (p=0.059). 15 and 11 died of lung cancer, respectively (p=0.428). Conclusion CT screening for lung cancer brings forward early disease, and at this point no stage shift or reduction in mortality was observed. More lung cancers were diagnosed in the screening group, indicating some degree of overdiagnosis and need for longer follow-up.


American Journal of Respiratory and Critical Care Medicine | 2016

Results of the Randomized Danish Lung Cancer Screening Trial with Focus on High-Risk Profiling

Mathilde M. W. Wille; Asger Dirksen; Haseem Ashraf; Zaigham Saghir; Karen S. Bach; John Brodersen; Paul Clementsen; Hanne Sand Hansen; Klaus Richter Larsen; Jann Mortensen; Jakob F. Rasmussen; Niels Seersholm; Birgit Guldhammer Skov; Laura H. Thomsen; Philip Tønnesen; Jesper Holst Pedersen

RATIONALE As of April 2015, participants in the Danish Lung Cancer Screening Trial had been followed for at least 5 years since their last screening. OBJECTIVES Mortality, causes of death, and lung cancer findings are reported to explore the effect of computed tomography (CT) screening. METHODS A total of 4,104 participants aged 50-70 years at the time of inclusion and with a minimum 20 pack-years of smoking were randomized to have five annual low-dose CT scans (study group) or no screening (control group). MEASUREMENTS AND MAIN RESULTS Follow-up information regarding date and cause of death, lung cancer diagnosis, cancer stage, and histology was obtained from national registries. No differences between the two groups in lung cancer mortality (hazard ratio, 1.03; 95% confidence interval, 0.66-1.6; P = 0.888) or all-cause mortality (hazard ratio, 1.02; 95% confidence interval, 0.82-1.27; P = 0.867) were observed. More cancers were found in the screening group than in the no-screening group (100 vs. 53, respectively; P < 0.001), particularly adenocarcinomas (58 vs. 18, respectively; P < 0.001). More early-stage cancers (stages I and II, 54 vs. 10, respectively; P < 0.001) and stage IIIa cancers (15 vs. 3, respectively; P = 0.009) were found in the screening group than in the control group. Stage IV cancers were nonsignificantly more frequent in the control group than in the screening group (32 vs. 23, respectively; P = 0.278). For the highest-stage cancers (T4N3M1, 21 vs. 8, respectively; P = 0.025), this difference was statistically significant, indicating an absolute stage shift. Older participants, those with chronic obstructive pulmonary disease, and those with more than 35 pack-years of smoking had a significantly increased risk of death due to lung cancer, with nonsignificantly fewer deaths in the screening group. CONCLUSIONS No statistically significant effects of CT screening on lung cancer mortality were found, but the results of post hoc high-risk subgroup analyses showed nonsignificant trends that seem to be in good agreement with the results of the National Lung Screening Trial. Clinical trial registered with www.clinicaltrials.gov (NCT00496977).


Thorax | 2011

Multimodality approach to mediastinal staging in non-small cell lung cancer. Faults and benefits of PET-CT: a randomised trial

Barbara M. Fischer; Jann Mortensen; Hanne Hansen; Peter Vilmann; Søren S Larsen; Annika Loft; Anne K Bertelsen; Jesper Ravn; Paul Clementsen; Asbjørn Høegholm; Klaus Richter Larsen; Asger Dirksen; Birgit Skov; Mark Krasnik; Liselotte Højgaard; Ulrik Lassen

Background Correct mediastinal staging is a cornerstone in the treatment of patients with non-small cell lung cancer. A large range of methods is available for this purpose, making the process of adequate staging complex. The objective of this study was to describe faults and benefits of positron emission tomography (PET)-CT in multimodality mediastinal staging. Methods A randomised clinical trial was conducted including patients with a verified diagnosis of non-small cell lung cancer, who were considered operable. Patients were assigned to staging with PET-CT (PET-CT group) followed by invasive staging (mediastinoscopy and/or endoscopic ultrasound with fine needle aspiration (EUS-FNA)) or invasive staging without prior PET-CT (conventional work up (CWU) group). Mediastinal involvement (dichotomising N stage into N0–1 versus N2–3) was described according to CT, PET-CT, mediastinoscopy, EUS-FNA and consensus (based on all available information), and compared with the final N stage as verified by thoracotomy or a conclusive invasive diagnostic procedure. Results A total of 189 patients were recruited, 98 in the PET-CT group and 91 in the CWU group. In an intention-to-treat analysis the overall accuracy of the consensus N stage was not significantly higher in the PET-CT group than in the CWU group (90% (95% confidence interval 82% to 95%) vs 85% (95% CI 77% to 91%)). Excluding the patients in whom PET-CT was not performed (n=14) the difference was significant (95% (95% CI 88% to 98%) vs 85% (95% CI 77% to 91%), p=0.034). This was mainly based on a higher sensitivity of the staging approach including PET-CT. Conclusion An approach to lung cancer staging with PET-CT improves discrimination between N0–1 and N2–3. In those without enlarged lymph nodes and a PET-negative mediastinum the patient may proceed directly to surgery. However, enlarged lymph nodes on CT needs confirmation independent of PET findings and a positive finding on PET-CT needs confirmation before a decision on surgery is made. Clinical trial number NCT00867412.


Medicine and Science in Sports and Exercise | 2008

Airway Responses to Eucapnic Hyperpnea, Exercise, and Methacholine in Elite Swimmers

Lars C. Pedersen; Simon Winther; Vibeke Backer; Sandra D. Anderson; Klaus Richter Larsen

PURPOSE The International Olympic Committee Medical Commission (IOC-MC) requires athletes to provide the result of an objective test to support a diagnosis of asthma or exercise-induced bronchoconstriction (EIB) if they want to inhale a beta-2-agonist. The purpose of the study was to evaluate the airway response to a methacholine challenge and to hyperpnea induced by exercise in the field and in the laboratory or that induced voluntarily by eucapnic hyperpnea in a group of female elite swimmers. METHODS Sixteen female nonasthmatic elite swimmers performed a eucapnic voluntary hyperpnea (EVH) test, a field-based exercise test (FBT), a laboratory-based exercise test (LBT), and a methacholine challenge. The criteria suggested by the IOC-MC were used to define a positive response to the challenges (EVH, field test, and laboratory test: minimum 10% decrease in FEV1; methacholine: PD20 < or = 2 micromol). RESULTS Eight swimmers (50%) had at least one positive test to hyperpnea. Five were identified with the EVH test, four with FBT, and four with LBT. None were identified using methacholine. Three swimmers with airway hyperresponsiveness to exercise would have been identified using a higher cutoff for methacholine (PD20 < or = 8 micromol). CONCLUSIONS The EVH test is the test that diagnoses most swimmers with an abnormal response to hyperpnea, but not all cases of EIB are identified with the EVH test. Performing a methacholine test using IOC-MCs cutoff value does not improve the chances of diagnosing EIB. We recommend performing the EVH test when diagnosing and evaluating EIB in elite swimmers and if EVH test negative then proceeding to a strenuous LBT.


Apmis | 2015

The prevalence of EGFR mutations in non-small cell lung cancer in an unselected Caucasian population.

Birgit Guldhammer Skov; Estrid Høgdall; Paul Clementsen; Mark Krasnik; Klaus Richter Larsen; Jens Benn Sørensen; Torsten Skov; Anders Mellemgaard

EGFR mutation frequencies in unselected Caucasian populations are unknown. This study assesses the prevalence of EGFR mutations in an unselected population‐based cohort, and the correlation between mutation and gender, age, ethnicity, smoking habits, and pathological data. NSCLC patients diagnosed in a well‐defined Danish population were included. The type of the diagnostic material, and data on smoking were registered. The mutation analyses were investigated by Therascreen EGFR RGQ‐PCR Kit or Sanger sequencing. A total of 658 men and 598 women were included. 6.2% were never smokers, 38.9% were ex‐smokers, and 54.9% were current smokers. One thousand one hundred and sixty‐one (92.4%) patients had sufficient material for mutation analysis. Cytological material was used for 38% of the mutation analyses. 5.4% had mutation in the EGFR gene (4.3% men/6.7% women). 87% were activating mutations. 8.0% of adenocarcinomas, and 1.9% of squamous cell carcinomas were mutated. 29.4%, 4.4% and 2.9% of never, ex‐ and current smokers were mutated (p < 0.001). No difference in mutation rate was observed between patients with cytology only, histology only or both cytology and histology available. 5.4% of the patients had EGFR mutation. Adenocarcinomas were mutated more often (8.0%) than squamous cell carcinomas (1.9%). Mutations were found in never smokers as well as in former and current smokers. No difference in gender and age regarding mutation status was observed. EGFR mutations analysis was possible in almost all patients with no difference between cytology and histology specimens.


Radiotherapy and Oncology | 2016

Liquid fiducial marker performance during radiotherapy of locally advanced non small cell lung cancer

Jonas Scherman Rydhög; Steen Riisgaard Mortensen; Klaus Richter Larsen; Paul Clementsen; Rasmus Irming Jølck; Mirjana Josipovic; Marianne C. Aznar; Lena Specht; Thomas Lars Andresen; Per Munck af Rosenschöld; Gitte Fredberg Persson

BACKGROUND AND PURPOSE We analysed the positional and structural stability of a long-term biodegradable liquid fiducial marker (BioXmark) for radiotherapy in patients with locally advanced lung cancer. MATERIAL AND METHODS Markers were injected via endoscopic- or endobronchial ultrasound in lymph nodes and reachable primary tumours. Marker volume and Hounsfield Units (HU) changing rates were estimated using breath-hold CBCT. Inter-fraction variation in marker position relative to gross tumour volume (GTV) position was established, as well as the inter-fraction variation in mediastinal marker registration relative to a carina registration through the treatment. RESULTS Fifteen patients were included and 29 markers analysed. All markers that were in situ at planning were visible through the treatment. Mean HU was 902±165HU for lymph node and 991±219HU for tumour markers. Volume degradation rates were -5% in lymph nodes and -23% in primary tumours. Three-dimensional inter-fraction variation for marker position relative to the GTV position was -0.1±0.7mm in lymph nodes and -1.5±2.3mm in primary tumours. Inter-fraction variations in marker registration relative to carina registration were -0.4±1.2mm in left-right, 0.2±2.0mm in anterior-posterior and -0.5±2.0mm in cranio-caudal directions. CONCLUSIONS The liquid fiducial markers were visible and stable in size and position throughout the treatment course.


Integrative Cancer Therapies | 2016

Perioperative Rehabilitation in Operable Lung Cancer Patients (PROLUCA) A Feasibility Study

Maja S. Sommer; Karen Trier; Jette Vibe-Petersen; Malene Missel; Merete Sanvig Christensen; Klaus Richter Larsen; Seppo W. Langer; Carsten Hendriksen; Paul Clementsen; Jesper Holst Pedersen; Henning Langberg

Introduction. Surgical resection in patients with non–small cell lung cancer (NSCLC) may be associated with significant morbidity, functional limitations, and decreased quality of life. Objectives. The safety and feasibility of a preoperative and early postoperative rehabilitation program in patients operated for NSCLC was determined in a nonhospital setting, with focus on high-intensity interval exercise. Methods. Forty patients with biopsy-proven NSCLC stages I to IIIa referred for surgical resection at the Department of Cardiothoracic Surgery RT, Rigshospitalet, University of Copenhagen, were randomly assigned to 1 of 4 groups (3 intervention groups and 1 control group). The preoperative intervention consisted of a home-based exercise program, while the postoperative exercise program comprised a supervised group exercise program involving resistance and high-intensity interval cardiorespiratory exercise 2 hours weekly for 12 weeks combined with individual counseling. The study endpoints were inclusion rate, adherence, and number of adverse events. Results. Forty patients (of 124 screened; 32%) were included and randomized into the 4 groups. The postoperative exercise was completed by 73% of the patients randomized to this intervention. No adverse events were observed, indicating that the early postoperative exercise program is safe. The preoperative home-based exercise program was not feasible due to interfering diagnostic procedures and fast-track surgery that left only 1 to 2 weeks between diagnosis and surgery. Conclusion. The early postoperative exercise program for patients with NSCLC was safe and feasible, but in a fast-track set up, a preoperative home-based exercise program was not feasible for this population.


European Clinical Respiratory Journal | 2016

Bronchoscopy as a supplement to computed tomography in patients with haemoptysis may be unnecessary.

Klaus Nielsen; Magnus Gottlieb; Sara Colella; Zaigham Saghir; Klaus Richter Larsen; Paul Clementsen

Background Haemoptysis is a common symptom and can be an early sign of lung cancer. Careful investigation of patients with haemoptysis may lead to early diagnosis. The strategy for investigation of these patients, however, is still being debated. Objectives We studied whether the combination of computed tomography (CT) and bronchoscopy had a higher sensitivity for malignant and non-malignant causes of haemoptysis than CT alone. Methods The study was a retrospective, non-randomised, two-centre study and included patients who were referred from primary care for the investigation of haemoptysis. Results A total of 326 patients were included in the study (mean age 60.5 [SD 15.3] years, 63.3% male). The most common aetiologies of haemoptysis were cryptogenic (52.5%), pneumonia (16.3%), emphysema (8.0%), bronchiectasis (5.8%) and lung cancer (4.0%). In patients diagnosed with lung cancer, bronchoscopy, CT and the combination of bronchoscopy and CT had a sensitivity of 0.61, 0.92 (p<0.05) and 0.97 (p=0.58), respectively. In patients with non-malignant causes of haemoptysis, most aetiologies were diagnosed by CT and comprised mainly pneumonia, emphysema and bronchiectasis. Bronchoscopy did not reveal these conditions and the sensitivity to these conditions was not increased by combining CT and bronchoscopy. Conclusions CT can stand alone as a diagnostic workup for patients with haemoptysis referred to an outpatient clinic. Bronchoscopy does not identify any malignant aetiologies not already diagnosed by CT. Combining the two test modalities does not result in a significant increase in sensitivity for malignant or non-malignant causes of haemoptysis.


Radiotherapy and Oncology | 2017

Liquid fiducial marker applicability in proton therapy of locally advanced lung cancer

Jonas Scherman Rydhög; Rosalind Perrin; Rasmus Irming Jølck; F. Gagnon-Moisan; Klaus Richter Larsen; Paul Clementsen; Steen Riisgaard de Blanck; Gitte Fredberg Persson; Damien C. Weber; Tony Lomax; Thomas Lars Andresen; Per Munck af Rosenschöld

BACKGROUND AND PURPOSE We investigated the clinical applicability of a novel liquid fiducial marker (LFM) for image-guided pencil beam scanned (PBS) proton therapy (PBSPT) of locally advanced lung cancer (LALC). MATERIALS AND METHODS The relative proton stopping power (RSP) of the LFM was calculated and measured. Dose perturbations of the LFM and three solid markers, in a phantom, were measured. PBSPT treatment planning on computer tomography scans of five patients with LALC with the LFM implanted was performed with 1-3 fields. RESULTS The RSP was experimentally determined to be 1.164 for the LFM. Phantom measurements revealed a maximum relative deviation in dose of 4.8% for the LFM in the spread-out Bragg Peak, compared to 12-67% for the solid markers. Using the experimentally determined RSP, the maximum proton range error introduced by the LFM is about 1mm. If the marker was displaced at PBSPT, the maximum dosimetric error was limited to 2 percentage points for 3-field plans. CONCLUSION The dose perturbations introduced by the LFM were considerably smaller than the solid markers investigated. The RSP of the fiducial marker should be corrected in the treatment planning system to avoid errors. The investigated LFM introduced clinically acceptable dose perturbations for image-guided PBSPT of LALC.

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Jann Mortensen

University of Copenhagen

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Birgit Guldhammer Skov

Copenhagen University Hospital

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Asger Dirksen

University of Copenhagen

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Rasmus Irming Jølck

Technical University of Denmark

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Annika Loft

University of Copenhagen

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