64 research outputs found
Development of CNS-type Primitive Neuroectodermal Tumor in Metastatic Testicular Mixed Germ Cell Tumor.
A 29-year-old man presenting with a retroperitoneal mass was found to have a testis lesion consistent with mixed germ cell tumor and the RPLND specimen showed teratoma with an area of central nervous system-type primitive neuroectodermal tumor (PNET) not present in the testis. Whether such primitive tumor components represent a de novo tumor component or represent progression from existing neuroepithelial teratomatous elements is unclear. Given the high likelihood of residual tumor and possibility of malignant transformation, post-chemotherapy RPLND remains vital in treating patients with testis cancer. PNET is chemo-resistant and lesions should be resected, without clear evidence for adjuvant chemotherapy
An Investigation into the Effects of Pre-training Data Distributions for Pathology Report Classification
Pre-trained transformer models have demonstrated success across many natural
language processing (NLP) tasks. In applying these models to the clinical
domain, a prevailing assumption is that pre-training language models from
scratch on large-scale biomedical data results in substantial improvements. We
test this assumption with 4 pathology classification tasks on a corpus of 2907
prostate cancer pathology reports. We evaluate 5 transformer pre-trained models
that are the same size but differ in pre-training corpora. Specifically, we
analyze 3 categories of models: 1)General-domain: BERT and Turing Natural
Language Representation (TNLR) models, which use general corpora for
pre-training, 2)Mixed-domain: BioBERT which is obtained from BERT by including
PubMed abstracts in pre-training and Clinical BioBERT which additionally
includes MIMIC-III clinical notes and 3)Domain-specific: PubMedBERT which is
pre-trained from scratch on PubMed abstracts. We find the mixed-domain and
domain-specific models exhibit faster feature disambiguation during
fine-tuning. However, the domain-specific model, PubMedBERT, can overfit to
minority classes when presented with class imbalance, a common scenario in
pathology report data. At the same time, the mixed-domain models are more
resistant to overfitting. Our findings indicate that the use of general natural
language and domain-specific corpora in pre-training serve complementary
purposes for pathology report classification. The first enables resistance to
overfitting when fine-tuning on an imbalanced dataset while the second allows
for more accurate modelling of the fine-tuning domain. An expert evaluation is
also conducted to reveal common outlier modes of each model. Our results could
inform better fine-tuning practices in the clinical domain, to possibly
leverage the benefits of mixed-domain models for imbalanced downstream
datasets
Using an abdominal phantom to teach urology residents ultrasound-guided percutaneous needle placement
ABSTRACT Introduction: To assess the effect of a hands-on ultrasound training session to teach urologic trainees ultrasound-guided percutaneous needle placement. Materials and methods: University of California, San Francisco (UCSF) urology residents completed a time trial, placing a needle into a phantom model target under ultrasound guidance. Participants were randomized into three educational exposure groups: Group 1's time trial occurred prior to any teaching intervention, group 2's after experiencing a hands-on training module, and group 3's after exposure to both the training module and one-on-one attending feedback. Needle placement speed and accuracy as well as trainees' perceived confidence in utilizing ultrasound were measured. Results: The study cohort consisted of 15 resident trainees. Seven were randomized to group 1, three to group 2, and five to group 3. All residents reported minimal prior ultrasound experience. Their confidence in using ultrasound improved significantly after completing the training module with the most significant improvement seen among junior residents. Time to needle placement was fastest after receiving attending feedback (46.6sec in group 3 vs. 82.7sec in groups 1 and 2, p<0.01). Accuracy also improved with attending feedback, though the number of repositioning attempts did not differ significantly between groups. Conclusions: A hands-on training module and use of an abdominal phantom trainer increased resident confidence and skill in their use of ultrasound to guide percutaneous needle positioning. Attending feedback is critical for improving accuracy in needle guidance toward a target. Ultrasound-guided needle positioning is a teachable skill and can be applicable to multiple urologic procedures
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