Samuel Bobholz

Dr. Samuel Bobholz


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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6 September 2023 in Cancers
Verified
Journal Article
Open access
PDF file
SDSavannah Rae Duenweg
Savannah Rae Duenweg
SBSamuel Bobholz
Samuel Bobholz
MBMichael John Barrett
Michael John Barrett
ALAllison K. Lowman
Allison K. Lowman
AWAleksandra Winiarz
Aleksandra Winiarz
PLPeter S. LaViolette
Peter S. LaViolette
Prostate cancer (PCa) is the most diagnosed non-cutaneous cancer in men. Despite therapies such as radical prostatectomy, which is considered curative, distant metastases may form, resulting in biochemical recurrence (BCR). This study used radiomic features calculated from multi-parametric magnetic resonance imaging (MP-MRI) to evaluate their ability to predict BCR and PCa presence. Data from a total of 279 patients, of which 46 experienced BCR, undergoing MP-MRI prior to surgery were assessed for this study. After surgery, the prostate was sectioned using patient-specific 3D-printed slicing jigs modeled using the T2-weighted imaging (T2WI). Sectioned tissue was stained, digitized, and annotated by a GU-fellowship trained pathologist for cancer presence. Digitized slides and annotations were co-registered to the T2WI and radiomic features were calculated across the whole prostate and cancerous lesions. A tree regression model was fitted to assess the ability of radiomic features to predict BCR, and a tree classification model was fitted with the same radiomic features to classify regions of cancer. We found that 10 radiomic features predicted eventual BCR with an AUC of 0.97 and classified cancer at an accuracy of 89.9%. This study showcases the application of a radiomic feature-based tool to screen for the presence of prostate cancer and assess patient prognosis, as determined by biochemical recurrence.

9 September 2020 in Journal of Medical Imaging
Verified
Journal Article
Open access
PDF file
SMSean D. McGarry
Sean D. McGarry
JBJohn D. Bukowy
John D. Bukowy
KIKenneth A Iczkowski
Kenneth A Iczkowski
ALAllison K. Lowman
Allison K. Lowman
MBMichael Brehler
Michael Brehler
PLPeter S. LaViolette
Peter S. LaViolette
Despite being the most commonly diagnosed noncutaneous cancer in men, improved prostate cancer screening and aggressive therapies have led to a high five-year overall survival rate.1 There is still substitutional morbidity associated with overtreatment of indolent disease due to the semi-invasive nature of the current diagnostic paradigm, the 12-core transrectal ultrasound-guided biopsy.2 As such, there has been a growing interest in recent years for developing improved strategies for differentiating aggressive from indolent prostate cancer noninvasively.

13 October 2020 in Journal of Medical Imaging
Verified
Journal Article
Open access
PDF file
JBJohn D. Bukowy
John D. Bukowy
HFHalle Foss
Halle Foss
SMSean D. McGarry
Sean D. McGarry
ALAllison K. Lowman
Allison K. Lowman
SHSarah L. Hurrell
Sarah L. Hurrell
PLPeter S. LaViolette
Peter S. LaViolette
It is estimated that one in seven men will develop prostate cancer (PCa) in their lifetime and that PCa itself accounts for one in five new cancer diagnoses.1 Invasive removal of prostate tissue is currently required to confirm cancer diagnosis and drive treatment. From these samples, pathologists use the well-characterized Gleason criteria2,3 to interpret histomorphometric features and grade the tissues,4 which can then be used to assign a grade group (GG).5 While these grading criteria have been shown to hold great prognostic value, they are inherently subjective, relying on a pathologist’s interpretation.6

3 July 2023 in Preprints.org
Verified
Preprint
Open access
PDF file
SDSavannah Rae Duenweg
Savannah Rae Duenweg
SBSamuel Bobholz
Samuel Bobholz
MBMichael John Barrett
Michael John Barrett
ALAllison K. Lowman
Allison K. Lowman
AWAleksandra Winiarz
Aleksandra Winiarz
PLPeter S. LaViolette
Peter S. LaViolette
Prostate cancer (PCa) is the most diagnosed non-cutaneous cancer in men. Despite therapies such as radical prostatectomy, which is considered curative, distant metastases may form resulting in biochemical recurrence (BCR). This study used radiomic features calculated from multi-parametric magnetic resonance imaging (MP-MRI) to evaluate their ability to predict BCR and PCa presence. Data from a total of 279 patients, of which 46 experienced BCR, undergoing MP-MRI prior to surgery were assessed for this study. After surgery, the prostate was sectioned using patient-specific 3D-printed slicing jigs modeled using the T2-weighted imaging (T2WI). Sectioned tissue was stained, digitized, and annotated by a GU-fellowship trained pathologist for cancer presence. Digitized slides and annotations were co-registered to the T2WI and radiomic features were calculated across the whole prostate and cancerous lesions. A tree regression model was fitted to assess the ability of radiomic features to predict BCR, and a tree classification model was fitted with the same radiomic features to classify regions of cancer. We found that 10 radiomic features predict eventual BCR with an AUC of 0.97 and classifying cancer at an accuracy of 89.9%. This study showcases the application for a radiomics-based tool to screen for the presence of prostate cancer and assess patient prognosis, as determined by biochemical recurrence.

2 March 2022 in Tomography
Verified
Journal Article
Open access
PDF file
SDSavannah Rae Duenweg
Savannah Rae Duenweg
XFXi Fang
Xi Fang
SBSamuel Bobholz
Samuel Bobholz
ALAllison K. Lowman
Allison K. Lowman
MBMichael Brehler
Michael Brehler
PLPeter S. LaViolette
Peter S. LaViolette
The presence and extent of cribriform patterned Gleason 4 (G4) glands are associated with poor prognosis following radical prostatectomy. This study used whole-mount prostate histology and multiparametric magnetic resonance imaging (MP-MRI) to evaluate diffusion differences in G4 gland morphology. Fourty-eight patients underwent MP-MRI prior to prostatectomy, of whom 22 patients had regions of both G4 cribriform glands and G4 fused glands (G4CG and G4FG, respectively). After surgery, the prostate was sliced using custom, patient-specific 3D-printed slicing jigs modeled according to the T2-weighted MR image, processed, and embedded in paraffin. Whole-mount hematoxylin and eosin-stained slides were annotated by our urologic pathologist and digitally contoured to differentiate the lumen, epithelium, and stroma. Digitized slides were co-registered to the T2-weighted MRI scan. Linear mixed models were fitted to the MP-MRI data to consider the different hierarchical structures at the patient and slide level. We found that Gleason 4 cribriform glands were more diffusion-restricted than fused glands.