Robert Sifrer

Prof. Dr. Robert Sifrer


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

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30 October 2017 in European Archives of Oto-Rhino-Laryngology
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RSRobert Sifrer
Robert Sifrer
JRJohannes A. Rijken
Johannes A. Rijken
CLC. René Leemans
C. René Leemans
SESimone E. J. Eerenstein
Simone E. J. Eerenstein
SWStijn van Weert
Stijn van Weert
RRRico N. P. M. Rinkel
Rico N. P. M. Rinkel
A newly proposed classification by the European Laryngological Society (ELS) of glottic lesions by narrow-band imaging (NBI) divides their vascular patterns into longitudinal and perpendicular ones. The latter are further subdivided into the wide and narrow patterns. The longitudinal, wide, and narrow patterns are characteristic of benign disease, papilloma, and malignancy, respectively. The aim of the study was to investigate the diagnostic effectiveness of the classification. Forty patients with glottic lesions underwent microlaryngoscopy. The vascular patterns of all vocal cords were defined with NBI. The affected vocal cords were histologically analysed and comprised the arm (A). Unaffected vocal cords were not histologically analysed but followed-up and comprised the arm (B) and were regarded as true negatives if no suspicious changes appeared during the follow-up. The vocal cords from the arm A were categorised into the benign and malignant group according to the histologic result. The ratio of vascular patterns was determined and the groups were statistically compared using the Chi-square test and Fisher’s exact test. Perpendicular changes were observed in 36.6% (9/26) of benign diseases and in 100% (23/23) of cancer conditions (p < 0.001). Wide perpendicular changes appeared only in papillomas (6/6) while narrow ones mostly in malignancies (23/26) and also in benign conditions (3/26) (p < 0.001). The sensitivity, specificity, positive and negative predictive values, and accuracy were 100, 95, 88, 100 and 96%, respectively. The new ELS classification can be used effectively and safely to differentiate malignant from benign disease.

8 March 2016 in European Archives of Oto-Rhino-Laryngology
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RSRobert Sifrer
Robert Sifrer
AAAleksandar Aničin
Aleksandar Aničin
MPMaja Perme Pohar
Maja Perme Pohar
MŽMiha Žargi
Miha Žargi
PPPeter Pukl
Peter Pukl
PSPrimož Strojan
Primož Strojan

27 September 2021 in Cancers
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Primož StrojanPrimož Strojan
Primož Strojan
RSRobert Sifrer
Robert Sifrer
Alfio FerlitoAlfio Ferlito
Alfio Ferlito
CKCvetka Grašič Kuhar
Cvetka Grašič Kuhar
BLBoštjan Lanišnik
Boštjan Lanišnik
Nina ZidarNina Zidar
Nina Zidar
Neuroendocrine carcinomas (NECs) of the head and neck are rare and the experience scanty. The Cancer Registry of Slovenia database was used to identify cases of laryngeal and pharyngeal NECs diagnosed between 1995–2020. Biopsies were analyzed for the expression of standard neuroendocrine markers (synaptophysin, chromogranin, CD56), INSM1, Ki-67, p16, and PD-L1 (using the combined positive score, CPS). In situ hybridization for human papillomavirus (HPV) and Epstein–Barr virus (EBV) was performed. Twenty patients (larynx, 12; pharynx, 8) were identified. One tumor was well differentiated (WD), five were moderately differentiated (MD), and 14 were poorly differentiated (PD). Disease control was achieved solely by surgery in 4/4 MD/PD T1-2N0-1 tumors. Eight patients died of the disease, seven of which were due to distant metastases. All three traditional markers were positive in 11/17 NECs and the INSM1 marker in all 20 tumors. Two of fourteen p16-positive tumors were HPV-positive, but all three nasopharyngeal NECs were EBV-negative. Three tumors had CPSs ≥ 1. In conclusion, INSM1 was confirmed to be a reliable marker of neuroendocrine differentiation. Except in WD and early-stage MD/PD tumors, aggressive multimodal therapy is needed; the optimal systemic therapy remains to be determined. p16, HPV, and EBV seem to bear no prognostic information.

28 February 2020 in European Archives of Oto-Rhino-Laryngology
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Journal Article
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RSRobert Sifrer
Robert Sifrer
MŠMaja Šereg-Bahar
Maja Šereg-Bahar
NGNina Gale
Nina Gale
IHIrena Hočevar-Boltežar
Irena Hočevar-Boltežar

15 November 2016 in The Laryngoscope
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Journal Article
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RSRobert Sifrer
Robert Sifrer
JUJure Urbančič
Jure Urbančič
PSPrimož Strojan
Primož Strojan
AAAleksandar Aničin
Aleksandar Aničin
MŽMiha Žargi
Miha Žargi

5 September 2020 in European Archives of Oto-Rhino-Laryngology
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Journal Article
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RSRobert Sifrer
Robert Sifrer
JUJure Urbančič
Jure Urbančič
CPCesare Piazza
Cesare Piazza
SWStijn van Weert
Stijn van Weert
FGFrancisco García-Purriños
Francisco García-Purriños
AAAleksandar Aničin
Aleksandar Aničin