Johannes Krisam

Dr. Johannes Krisam

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

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

Representative Publications

View All Publications
24 January 2019 in PLOS Medicine
Verified
Journal Article
Open access
PDF file
JKJakob Nikolas Kather
Jakob Nikolas Kather
JKJohannes Krisam
Johannes Krisam
PCPornpimol Charoentong
Pornpimol Charoentong
TLTom Luedde
Tom Luedde
EHEsther Herpel
Esther Herpel
NHNiels Halama
Niels Halama
For virtually every patient with colorectal cancer (CRC), hematoxylin–eosin (HE)–stained tissue slides are available. These images contain quantitative information, which is not routinely used to objectively extract prognostic biomarkers. In the present study, we investigated whether deep convolutional neural networks (CNNs) can extract prognosticators directly from these widely available images. We hand-delineated single-tissue regions in 86 CRC tissue slides, yielding more than 100,000 HE image patches, and used these to train a CNN by transfer learning, reaching a nine-class accuracy of >94% in an independent data set of 7,180 images from 25 CRC patients. With this tool, we performed automated tissue decomposition of representative multitissue HE images from 862 HE slides in 500 stage I–IV CRC patients in the The Cancer Genome Atlas (TCGA) cohort, a large international multicenter collection of CRC tissue. Based on the output neuron activations in the CNN, we calculated a “deep stroma score,” which was an independent prognostic factor for overall survival (OS) in a multivariable Cox proportional hazard model (hazard ratio [HR] with 95% confidence interval [CI]: 1.99 [1.27–3.12], p = 0.0028), while in the same cohort, manual quantification of stromal areas and a gene expression signature of cancer-associated fibroblasts (CAFs) were only prognostic in specific tumor stages. We validated these findings in an independent cohort of 409 stage I–IV CRC patients from the “Darmkrebs: Chancen der Verhütung durch Screening” (DACHS) study who were recruited between 2003 and 2007 in multiple institutions in Germany. Again, the score was an independent prognostic factor for OS (HR 1.63 [1.14–2.33], p = 0.008), CRC-specific OS (HR 2.29 [1.5–3.48], p = 0.0004), and relapse-free survival (RFS; HR 1.92 [1.34–2.76], p = 0.0004). A prospective validation is required before this biomarker can be implemented in clinical workflows. In our retrospective study, we show that a CNN can assess the human tumor microenvironment and predict prognosis directly from histopathological images.

22 May 2019 in Conflict and Health
Verified
Journal Article
Open access
PDF file
Fekri DureabFekri Dureab
Fekri Dureab
MAMaysoon Al-Sakkaf
Maysoon Al-Sakkaf
OIOsan Ismail
Osan Ismail
NKNaasegnibe Kuunibe
Naasegnibe Kuunibe
JKJohannes Krisam
Johannes Krisam
AJAlbrecht Jahn
Albrecht Jahn
War in Yemen started three years ago, and continues unabated with a steadily rising number of direct and indirect victims thus leaving the majority of Yemen’s population in dire need of humanitarian assistance. The conflict adversely affects basic socioeconomic and health conditions across the country. This study analyzed the recent ongoing diphtheria outbreak in Yemen and in particular, the health system’s failure to ensure immunization coverage and respond to this outbreak. Data from the weekly bulletins of the national electronic Disease Early Warning System’s (eDEWS) daily diphtheria reports and district immunization coverage were analyzed. The number of diphtheria cases and deaths, and immunization coverage (DPT) were reviewed by district including the degree to which a district was affected by conflict using a simple scoring system. A logistic regression and bivariate correlation were applied using the annual immunization coverage per district to determine if there was an association between diphtheria, immunization coverage and conflict. The study results confirm the association between the increasing cases of diphtheria, immunization coverage and ongoing conflict. A total of 1294 probable cases of diphtheria were reported from 177 districts with an overall case fatality rate of 5.6%. Approximately 65% of the patients were children under 15 years, and 46% of the cases had never been vaccinated against diphtheria. The risk of an outbreak increased by 11-fold if the district was experiencing ongoing conflict p < 0.05. In the presence of conflict (whether past or ongoing), the risk of an outbreak decreased by 0.98 if immunization coverage was high p > 0.05. The conflict is continuously devastating the health system in Yemen with serious consequences on morbidity and mortality. Therefore, the humanitarian response should focus on strengthening health services including routine immunization procedures to avoid further outbreaks of life-threatening infectious diseases, such as diphtheria.

18 December 2014 in Health and Quality of Life Outcomes
Verified
Journal Article
Open access
PDF file
MKMartina Kamradt
Martina Kamradt
KBKayvan Bozorgmehr
Kayvan Bozorgmehr
JKJohannes Krisam
Johannes Krisam
TFTobias Freund
Tobias Freund
MKMarion Kiel
Marion Kiel
DODominik Ose
Dominik Ose
One of the most widely used self-reporting tools assessing diabetes self-management in English is the Summary of Diabetes Self-Care Activities (SDSCA) measure. To date there is no psychometric validated instrument in German to assess self-management in patients with diabetes mellitus. Therefore, this study aimed to translate the SDSCA into German and examine its psychometric properties. The English version of the SDSCA was translated into German following the guidelines for cultural adaptation. The German version of the SDSCA (SDSCA-G) was administered to a random sample of 315 patients with diabetes mellitus type 2. Reliability was analyzed using Cronbach’s alpha coefficient and item characteristics were assessed. Exploratory and confirmatory factor analysis (EFA and CFA) were carried out to explore the construct validity. A multivariable linear regression model was used to identify the influence of predictor variables on the SDSCA-G sum score. The Cronbach’s alpha for the SDSCA-G (all items) was α = 0.618 and an acceptable correlation between the SDSCA-G and Self-management Diabetes Mellitus-Questionnaire (SDQ) (ρ = 0.664) was identified. The EFA suggested a four factor construct as did the postulated model. The CFA showed the goodness of fit of the SDSCA-G. However, item 4 was found to be problematic regarding the analysis of psychometric properties. The omission of item 4 yielded an increase in Cronbach’s alpha (α = 0.631) and improvements of the factor structure and model fit. No statistically significant influences of predictor variables on the SDSCA-G sum score were observed. The revised German version of the SDSCA (SDSCA-G) is a reliable and valid tool assessing self-management in adults with type 2 diabetes in Germany.

27 March 2022 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
PHPhilipp Hoegen-Saßmannshausen
Philipp Hoegen-Saßmannshausen
KZK. S. Zhang
K. S. Zhang
ETE. Tonndorf-Martini
E. Tonndorf-Martini
Fabian WeykampFabian Weykamp
Fabian Weykamp
SRSebastian Regnery
Sebastian Regnery
JHJuliane Hörner-Rieber
Juliane Hörner-Rieber
Background: Stereotactic body radiotherapy (SBRT) is an established local treatment method for patients with hepatic oligometastasis or oligoprogression. Liver metastases often occur in close proximity to radiosensitive organs at risk (OARs). This limits the possibility to apply sufficiently high doses needed for optimal local control. Online MR-guided radiotherapy (oMRgRT) is expected to hold potential to improve hepatic SBRT by offering superior soft-tissue contrast for enhanced target identification as well as the benefit of gating and daily real-time adaptive treatment. The MAESTRO trial therefore aims to assess the potential advantages of adaptive, gated MR-guided SBRT compared to conventional SBRT at a standard linac using an ITV (internal target volume) approach. Methods: This trial is conducted as a prospective, randomized, three-armed phase II study in 82 patients with hepatic metastases (solid malignant tumor, 1–3 hepatic metastases confirmed by magnetic resonance imaging (MRI), maximum diameter of each metastasis ≤ 5 cm (in case of 3 metastases: sum of diameters ≤ 12 cm), age ≥ 18 years, Karnofsky Performance Score ≥ 60%). If a biologically effective dose (BED) ≥ 100 Gy (α/β = 10 Gy) is feasible based on ITV-based planning, patients will be randomized to either MRgRT or ITV-based SBRT. If a lesion cannot be treated with a BED ≥ 100 Gy, the patient will be treated with MRgRT at the highest possible dose. Primary endpoint is the non-inferiority of MRgRT at the MRIdian Linac® system compared to ITV-based SBRT regarding hepatobiliary and gastrointestinal toxicity CTCAE III or higher. Secondary outcomes investigated are local, locoregional (intrahepatic) and distant tumor control, progression-free survival, overall survival, possible increase of BED using MRgRT if the BED is limited with ITV-based SBRT, treatment-related toxicity, quality of life, dosimetric parameters of radiotherapy plans as well as morphological and functional changes in MRI. Potential prognostic biomarkers will also be evaluated. Discussion: MRgRT is known to be both highly cost- and labor-intensive. The MAESTRO trial aims to provide randomized, higher-level evidence for the dosimetric and possible consecutive clinical benefit of MR-guided, on-table adaptive and gated SBRT for dose escalation in critically located hepatic metastases adjacent to radiosensitive OARs. Trial registration: The study has been prospectively registered on August 30th, 2021: Clinicaltrials.gov, “Magnetic Resonance-guided Adaptive Stereotactic Body Radiotherapy for Hepatic Metastases (MAESTRO)”, NCT05027711.

4 May 2021 in Biometrical Journal
Verified
Journal Article
Open access
PDF file
MPMoritz Pohl
Moritz Pohl
JKJohannes Krisam
Johannes Krisam
MKMeinhard Kieser
Meinhard Kieser
Basket trials have become a virulent topic in medical and statistical research during the last decade. The core idea of them is to treat patients, who express the same genetic predisposition—either personally or their disease—with the same treatment irrespective of the location of the disease. The location of the disease defines each basket and the pathway of the treatment uses the common genetic predisposition among the baskets. This opens the opportunity to share information among baskets, which can consequently increase the information of the basket‐wise response with respect to the investigated treatment. This further allows dynamic decisions regarding futility and efficacy of individual baskets during the ongoing trial. Several statistical designs have been proposed on how a basket trial can be conducted and this has left an unclear situation with many options. The different designs propose different mathematical and statistical techniques, different decision rules, and also different trial purposes. This paper presents a broad overview of existing designs, categorizes them, and elaborates their similarities and differences. A uniform and consistent notation facilitates the first contact, introduction, and understanding of the statistical methodologies and techniques used in basket trials. Finally, this paper presents a modular approach for the construction of basket trials in applied medical science and forms a base for further research of basket trial designs and their techniques.

18 June 2019 in Trials
Verified
Journal Article
Open access
PDF file
CSCornelia Straßner
Cornelia Straßner
Eckhard FrickEckhard Frick
Eckhard Frick
GSGabriele Stotz-Ingenlath
Gabriele Stotz-Ingenlath
NBNicola Buhlinger-Göpfarth
Nicola Buhlinger-Göpfarth
JSJoachim Szecsenyi
Joachim Szecsenyi
SJStefanie Joos
Stefanie Joos
Strategies to improve the care of elderly, multimorbid patients frequently focus on implementing evidence-based knowledge by structured assessments and standardization of care. In Germany, disease management programs (DMPs), for example, are run by general practitioners (GPs) for this purpose. While the importance of such measures is undeniable, there is a risk of ignoring other dimensions of care which are essential, especially for elderly patients: their spiritual needs and personal resources, loneliness and social integration, and self-care (i.e., the ability of patients to do something on their own except taking medications to increase their well-being). The aim of this study is to explore whether combining DMPs with interventions to address these dimensions is feasible and has any impact on relevant outcomes in elderly patients with polypharmacy. An explorative, cluster-randomized controlled trial with general practices as the unit of randomization will be conducted and accompanied by a process evaluation. Patients aged 70 years or older with at least three chronic conditions receiving at least three medications participating in at least one DMP will be included. The control group will receive DMP as usual. In the intervention group, GPs will conduct a spiritual needs assessment during the routinely planned DMP appointments and explore whether the patient has a need for more social contact or self-care. To enable GPs to react to such needs, several aids will be provided by the study: a) training of GPs in spiritual needs assessment and training of medical assistants in patient counseling regarding self-care and social activity; b) access to a summary of regional social offers for seniors; and c) information leaflets on nonpharmacological interventions (e.g., home remedies) to be applied by patients themselves to reduce frequent symptoms in old age. The primary outcome is health-related self-efficacy (using the Self-Efficacy for Managing Chronic Disease 6-Item Scale (SES-6G)). Secondary outcomes are general self-efficacy (using the General Self-Efficacy Scale (GSES)), physical and mental health (using the Short-Form Health Survey (SF-12)), patient activation (using the Patient Activation Measure (PAM)), medication adherence (using the Medication Adherence Report Scale (MARS)), beliefs in medicine (using the Beliefs About Medicines Questionnaire (BMQ)), satisfaction with GP care (using selected items of the European Project on Patient Evaluation of General Practice (EUROPEP)), social contacts (using the 6-item Lubben Social Network Scale (LSNS-6)), and loneliness (using the 11-item De-Jong-Gierveld Loneliness Scale (DJGS-11)). Interviews will be conducted to assess the mechanisms, feasibility, and acceptability of the interventions. If the interventions prove to be effective and feasible, large-scale implementation should be sought and evaluated by a confirmatory design. German Clinical Trials Register (DRKS), DRKS00015696 . Registered on 22 January 2019.