Helder Oliveira

Dr. Helder Oliveira


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

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

Representative Publications

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16 April 2021 in Frontiers in Oncology
Verified
Journal Article
Open access
PDF file
CFCláudia Freitas
Cláudia Freitas
CSCatarina Sousa
Catarina Sousa
FMFrancisco Machado
Francisco Machado
MSMariana Serino
Mariana Serino
VSVanessa Santos
Vanessa Santos
VHVenceslau Hespanhol
Venceslau Hespanhol
Liquid biopsy is an emerging technology with a potential role in the screening and early detection of lung cancer. Several liquid biopsy-derived biomarkers have been identified and are currently under ongoing investigation. In this article, we review the available data on the use of circulating biomarkers for the early detection of lung cancer, focusing on the circulating tumor cells, circulating cell-free DNA, circulating micro-RNAs, tumor-derived exosomes, and tumor-educated platelets, providing an overview of future potential applicability in the clinical practice. While several biomarkers have shown exciting results, diagnostic performance and clinical applicability is still limited. The combination of different biomarkers, as well as their combination with other diagnostic tools show great promise, although further research is still required to define and validate the role of liquid biopsies in clinical practice.

1 April 2020 in The Breast
Verified
Journal Article
Open access
CMCarlos Mavioso
Carlos Mavioso
RARicardo J. Araújo
Ricardo J. Araújo
HOHelder Oliveira
Helder Oliveira
JAJoão C. Anacleto
João C. Anacleto
MVMaria Antónia Vasconcelos
Maria Antónia Vasconcelos
MCMaria João Cardoso
Maria João Cardoso
The deep inferior epigastric perforator (DIEP) is the most commonly used free flap in mastectomy reconstruction. Preoperative imaging techniques are routinely used to detect location, diameter and course of perforators, with direct intervention from the imaging team, who subsequently draw a chart that will help surgeons choosing the best vascular support for the reconstruction. In this work, the feasibility of using a computer software to support the preoperative planning of 40 patients proposed for breast reconstruction with a DIEP flap is evaluated for the first time. Blood vessel centreline extraction and local characterization algorithms are applied to identify perforators and compared with the manual mapping, aiming to reduce the time spent by the imaging team, as well as the inherent subjectivity to the task. Comparing with the measures taken during surgery, the software calibre estimates were worse for vessels smaller than 1.5 mm (P = 6e-4) but better for the remaining ones (P = 2e-3). Regarding vessel location, the vertical component of the software output was significantly different from the manual measure (P = 0.02), nonetheless that was irrelevant during surgery as errors in the order of 2-3 mm do not have impact in the dissection step. Our trials support that a reduction of the time spent is achievable using the automatic tool (about 2 h/case). The introduction of artificial intelligence in clinical practice intends to simplify the work of health professionals and to provide better outcomes to patients. This pilot study paves the way for a success story.

27 February 2020 in Scientific Reports
Verified
Journal Article
Open access
PDF file
GPGil Pinheiro
Gil Pinheiro
TPTânia Pereira
Tânia Pereira
CDCatarina Dias
Catarina Dias
CFCláudia Freitas
Cláudia Freitas
VHVenceslau Hespanhol
Venceslau Hespanhol
HOHelder Oliveira
Helder Oliveira
EGFR and KRAS are the most frequently mutated genes in lung cancer, being active research topics in targeted therapy. The biopsy is the traditional method to genetically characterise a tumour. However, it is a risky procedure, painful for the patient, and, occasionally, the tumour might be inaccessible. This work aims to study and debate the nature of the relationships between imaging phenotypes and lung cancer-related mutation status. Until now, the literature has failed to point to new research directions, mainly consisting of results-oriented works in a field where there is still not enough available data to train clinically viable models. We intend to open a discussion about critical points and to present new possibilities for future radiogenomics studies. We conducted high-dimensional data visualisation and developed classifiers, which allowed us to analyse the results for EGFR and KRAS biological markers according to different combinations of input features. We show that EGFR mutation status might be correlated to CT scans imaging phenotypes; however, the same does not seem to hold for KRAS mutation status. Also, the experiments suggest that the best way to approach this problem is by combining nodule-related features with features from other lung structures.

30 May 2024 in npj Precision Oncology
Verified
Journal Article
Open access
PDF file
MTMarco Teixeira
Marco Teixeira
FSFrancisco Silva
Francisco Silva
RFRui M. Ferreira
Rui M. Ferreira
TPTânia Pereira
Tânia Pereira
CFCeu Figueiredo
Ceu Figueiredo
HOHelder Oliveira
Helder Oliveira
Recent studies have shown that the microbiome can impact cancer development, progression, and response to therapies suggesting microbiome-based approaches for cancer characterization. As cancer-related signatures are complex and implicate many taxa, their discovery often requires Machine Learning approaches. This review discusses Machine Learning methods for cancer characterization from microbiome data. It focuses on the implications of choices undertaken during sample collection, feature selection and pre-processing. It also discusses ML model selection, guiding how to choose an ML model, and model validation. Finally, it enumerates current limitations and how these may be surpassed. Proposed methods, often based on Random Forests, show promising results, however insufficient for widespread clinical usage. Studies often report conflicting results mainly due to ML models with poor generalizability. We expect that evaluating models with expanded, hold-out datasets, removing technical artifacts, exploring representations of the microbiome other than taxonomical profiles, leveraging advances in deep learning, and developing ML models better adapted to the characteristics of microbiome data will improve the performance and generalizability of models and enable their usage in the clinic.

26 December 2023 in Computer Science Review
Verified
Journal Article
Closed access
TSTomás Santos
Tomás Santos
HOHelder Oliveira
Helder Oliveira
António CunhaAntónio Cunha
António Cunha

3 February 2025 in Image and Vision Computing
Verified
Journal Article
Open access
ANAna Filipa Rodrigues Nogueira
Ana Filipa Rodrigues Nogueira
HOHelder Oliveira
Helder Oliveira
LTLuis Teixeira
Luis Teixeira