Jan Loeffen

Dr. Jan Loeffen


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
25 April 2021 in Cancers
Verified
Journal Article
Open access
PDF file
BBBirgit Burkhardt
Birgit Burkhardt
MTMary Taj
Mary Taj
NGNathalie Garnier
Nathalie Garnier
VMVeronique Minard-Colin
Veronique Minard-Colin
VHVolkan Hazar
Volkan Hazar
Marta PillonMarta Pillon
Marta Pillon
Despite poor survival, controversies remain in the treatment for refractory or relapsed pediatric non-Hodgkin lymphoma (r/r NHL). The current project aimed to collect international experience on the re-induction treatment of r/r NHL, hematopoietic stem cell transplantation (HSCT), risk factors associated with outcome, and to suggest treatment recommendations. Inclusion criteria were (i) refractory disease, disease progression or relapse of any NHL subtype except anaplastic large cell lymphoma, (ii) age < 18 years at initial diagnosis, (iii) diagnosis in/after January 2000. Data from 639 eligible patients were evaluable. The eight-year probability of overall survival was 34 ± 2% with highly significant differences according to NHL subtypes: 28 ± 3% for 254 Burkitt lymphoma/leukemia, 50 ± 6% for 98 diffuse large B-cell lymphomas, 57 ± 8% for 41 primary mediastinal large B-cell lymphomas, 27 ± 3% for 177 T-lymphoblastic lymphomas, 52 ± 10% for 34 precursor-B-cell lymphoblastic lymphomas and 30 ± 9% for 35 patients with rare NHL subtypes. Subtype-specific factors associated with survival and treatment recommendations are suggested. There were no survivors without HSCT, except in few very small subgroups. Conclusions: There is an urgent need to further improve survival in r/r NHL. The current study provides the largest real-world series, which underlines the role of HSCT and suggests treatment recommendations.

21 March 2019 in European Journal of Pediatrics
Verified
Journal Article
Open access
PDF file
ECEster Coolen
Ester Coolen
JDJos M. T. Draaisma
Jos M. T. Draaisma
JLJan Loeffen
Jan Loeffen
Situation awareness (SA) is an important human factor and necessary for effective teamwork and patient safety. Human patient simulation (HPS) with video feedback allows for a safe environment where health care professionals can develop both technical and teamwork skills. It is, however, very difficult to observe and measure SA directly. The Situation Global Assessment Technique (SAGAT) was developed by Endsley to measure SA during real-time simulation. Our objective was to measure SA among team members during simulation of acute pediatric care scenarios on the medical ward and its relationship with team effectiveness. Twenty-four pediatric teams, consisting of two nurses, one resident, and one consultant, participated in three acute care scenarios, using high-fidelity simulation. Individual SAGAT scores contained shared and complimentary knowledge questions on different levels of SA. Within each scenario, two “freezes” were incorporated to assess SA of each team members’ clinical assessment and decision-making. SA overlap within the team (team SA) was computed and compared to indicators of team effectiveness (time to goal achievement, consensus on primary problem, diagnosis, task prioritization, leadership, and teamwork satisfaction). In 13 scenarios (18%), the team failed to reach the primary goals within the prescribed time of 1200 s. There was no significant difference in failure of goal completion between the scripted scenarios; however, there was a significant difference between scenario 3 and the other scenarios in time to goal completion. In all three scenarios, SA overlap level 2 (consensus on primary problem during the first freeze and consensus on diagnosis during the second freeze) leads to significantly faster achievement of the predefined goals. There was a strong relationship between team SA on the primary problem and diagnosis and team SA on task prioritization. Consensus on leadership within the team was low. Teamwork satisfaction was more influenced by knowledge about the importance of the assigned task than outcome of the scenario.

14 April 2022 in Cancers
Verified
Journal Article
Open access
PDF file
APAgata Pastorczak
Agata Pastorczak
AAAndishe Attarbaschi
Andishe Attarbaschi
SBSimon Bomken
Simon Bomken
ABArndt Borkhardt
Arndt Borkhardt
JBJutte van der Werff Ten Bosch
Jutte van der Werff Ten Bosch
JLJan Loeffen
Jan Loeffen
Patients with double stranded DNA repair disorders (DNARDs) (Ataxia Telangiectasia (AT) and Nijmegen Breakage syndrome (NBS)) are at a very high risk for developing hematological malignancies in the first two decades of life. The most common neoplasms are T-cell lymphoblastic malignancies (T-cell ALL and T-cell LBL) and diffuse large B cell lymphoma (DLBCL). Treatment of these patients is challenging due to severe complications of the repair disorder itself (e.g., congenital defects, progressive movement disorders, immunological disturbances and progressive lung disease) and excessive toxicity resulting from chemotherapeutic treatment. Frequent complications during treatment for malignancies are deterioration of pre-existing lung disease, neurological complications, severe mucositis, life threating infections and feeding difficulties leading to significant malnutrition. These complications make modifications to commonly used treatment protocols necessary in almost all patients. Considering the rarity of DNARDs it is difficult for individual physicians to obtain sufficient experience in treating these vulnerable patients. Therefore, a team of experts assembled all available knowledge and translated this information into best available evidence-based treatment recommendations.

12 August 2022 in Cancers
Verified
Journal Article
Open access
PDF file
EKEmma Kroeze
Emma Kroeze
LPLaura Arias Padilla
Laura Arias Padilla
MBMax Bakker
Max Bakker
JBJudith M. Boer
Judith M. Boer
MHMelanie M. Hagleitner
Melanie M. Hagleitner
JLJan Loeffen
Jan Loeffen
B-cell lymphoblastic lymphoma (BCP-LBL) and B-cell acute lymphoblastic leukemia (BCP-ALL) are the malignant counterparts of immature B-cells. BCP-ALL is the most common hematological malignancy in childhood, while BCP-LBL accounts for only 1% of all hematological malignancies in children. Therefore, BCP-ALL has been well studied and treatment protocols have changed over the last decades, whereas treatment for BCP-LBL has stayed roughly the same. Clinical characteristics of 364 pediatric patients with precursor B-cell malignancies were studied, consisting of BCP-LBL (n = 210) and BCP-ALL (n = 154) patients. Our results indicate that based on the clinical presentation of disease, B-cell malignancies probably represent a spectrum ranging from complete isolated medullary disease to apparent complete extramedullary disease. Hepatosplenomegaly and peripheral blood involvement are the most important discriminators, as both seen in 80% and 95% of the BCP-ALL patients and in 2% of the BCP-LBL patients, respectively. In addition, we show that the overall survival rates in this cohort differ significantly between BCP-LBL and BCP-ALL patients aged 1–18 years (p = 0.0080), and that the outcome for infants (0–1 years) with BCP-LBL is significantly decreased compared to BCP-LBL patients of all other pediatric ages (p < 0.0001).

21 December 2021 in HemaSphere
Verified
Journal Article
Open access
EKEmma Kroeze
Emma Kroeze
DWDilys D. Weijers
Dilys D. Weijers
MHMelanie M. Hagleitner
Melanie M. Hagleitner
HGHester A. de Groot-Kruseman
Hester A. de Groot-Kruseman
MJMarjolijn C. J. Jongmans
Marjolijn C. J. Jongmans
JLJan Loeffen
Jan Loeffen
This study describes the clinical characteristics of a complete Dutch T-cell lymphoblastic lymphoma (T-LBL) cohort, including second primary malignancies and comorbidities. We show that over 10% of patients in this complete T-LBL cohort have been diagnosed with a cancer predisposition syndrome (CPS), consisting almost exclusively of constitutional mismatch repair deficiency (CMMRD). The clinical characteristics of sporadic T-LBL patients were compared with T-LBL patients that have been diagnosed with CMMRD. This shows that disease presentation is comparable but that disease localization in CMMRD patients might be more localized. The percentage of CPS seems reliable considering the completeness of the cohort of Dutch T-LBL patients and might even be an underestimation (possibility of undiagnosed CPS patients in cohort). As the frequency of an underlying predisposition syndrome among T-LBL patients may be underestimated at present, we advocate for screening all pediatric T-LBL patients for the presence of germline mutations in mismatch repair genes.

13 November 2025 in Pediatric Radiology
Verified
Journal Article
Closed access
PDF file
IDIvana Dasic
Ivana Dasic
ALAnnemieke S. Littooij
Annemieke S. Littooij
NTNelleke Tolboom
Nelleke Tolboom
JLJan Loeffen
Jan Loeffen
PPPolina Pavicevic
Polina Pavicevic
RNRutger A.J. Nievelstein
Rutger A.J. Nievelstein