Nikolaos Kalakos

Dr. Nikolaos Kalakos

orcid

Research Focus & Metrics

Academic Career Length

2Years (2025-Present)

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

Representative Publications

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24 July 2025 in Diseases
Verified
Journal Article
Open access
PDF file
DZDimitrios Ioannis Ziogas
Dimitrios Ioannis Ziogas
NKNikolaos Kalakos
Nikolaos Kalakos
AMAnastasios Manolakis
Anastasios Manolakis
TVTheodoros Voulgaris
Theodoros Voulgaris
Ioannis A. VezakisIoannis A. Vezakis
Ioannis A. Vezakis
Ioannis PapanikolaouIoannis Papanikolaou
Ioannis Papanikolaou
Gastric cancer remains the fourth leading cause of cancer-related mortality worldwide. Advanced disease is associated with a poor prognosis, emphasizing the critical importance of early diagnosis through endoscopy. In addition to prognosis, disease extent also plays a pivotal role in guiding management strategies. Therefore, accurate locoregional staging (T and N staging) is vital for optimal prognostic and therapeutic planning. Endoscopic ultrasound (EUS) has long been an essential tool in this regard, with computed tomography (CT) and, more recently, positron emission tomography–computed tomography (PET–CT) serving as alternative imaging modalities. EUS is particularly valuable in the assessment of early gastric cancer, defined as tumor invasion confined to the mucosa or submucosa. These tumors are increasingly managed by endoscopic resection techniques offering improved post-treatment quality of life. EUS has also recently been utilized in the restaging process after neoadjuvant chemotherapy, aiding in the evaluation of tumor resectability and prognosis. Its performance may be further enhanced through the application of emerging techniques such as contrast-enhanced endosonography, EUS elastography, and artificial intelligence systems. In advanced, unresectable disease, complications such as gastric outlet obstruction (GOO) severely impact patient quality of life. In this setting, EUS-guided gastroenterostomy (EUS-GE) offers a less invasive alternative to surgical gastrojejunostomy. This review summarizes and critically analyzes the role of EUS in the context of gastric cancer, highlighting its applications across different stages of the disease and evaluating its performance relative to other diagnostic modalities.

6 September 2026 in Medicina
Verified
Journal Article
Open access
PDF file
PPPavlos Pardalis
Pavlos Pardalis
AIAlexandros Ioannou
Alexandros Ioannou
TDTheodoros Delidis
Theodoros Delidis
GKGeorgios Kokkotis
Georgios Kokkotis
GLGeorge Leonidakis
George Leonidakis
Evanthia P ZampeliEvanthia P Zampeli
Evanthia P Zampeli
Background and Objectives: Ozanimod is approved for the treatment of ulcerative colitis (UC). The aim of the present study was to evaluate the clinical, biochemical, and endoscopic outcomes. Materials and Methods: This was a retrospective, multicenter, cohort study. Clinical, biochemical, endoscopic, and safety data were collected from medical records. Τhe primary outcome was clinical response at week 12. Secondary outcomes included clinical remission, endoscopic improvement and remission, biochemical outcomes, treatment persistence, and safety. Clinical outcomes were assessed at weeks 12 and 48, while treatment persistence was evaluated over the complete 48-week follow-up period, using Kaplan–Meier analysis. Clinical response was defined as a ≥30% reduction in partial Mayo score and remission as a partial Mayo score < 3, with no individual sub-score > 1 and a rectal bleeding sub-score of 0. Clinical response and remission were primarily assessed using an observed-case approach, with an additional sensitivity analysis classifying discontinuations due to lack of efficacy as treatment failures. Results: A total of 79 patients were included (62.0% male; median age 44 years, IQR 31–56). Prior biologic exposure was recorded in 29.1%, and 64.6% were previously exposed to oral corticosteroids. Among patients with available clinical assessment at week 12 (n = 62), clinical response and clinical remission were achieved in 77.4% and 71.0%, respectively. Among patients with available data at week 12 (n = 32), endoscopic improvement was observed in 65.6%, while endoscopic remission was achieved in 15.6%. At week 48, among 26 evaluable patients, clinical response and remission rates were 96.2% and 84.6%, respectively; when discontinuations due to lack of efficacy were considered treatment failures, the corresponding rates were 52.1% and 45.8%. Treatment persistence did not differ significantly according to overall prior biologic exposure, whereas previous vedolizumab exposure was associated with lower treatment persistence over the week 48 follow-up (log-rank p = 0.037). In multivariable Cox regression, previous vedolizumab exposure remained associated with an increased hazard of treatment discontinuation (adjusted HR 3.07, 95% CI 1.23–7.67; p = 0.016). Adverse events were reported in 13.9% of patients. Conclusions: Ozanimod demonstrated good efficacy and a favorable safety profile in patients with moderate UC.