Prognostic Potential of Olfactory Function in Glioblastoma: a Prospective Observational Study

NCT ID: NCT06954636

Last Updated: 2025-07-08

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Total Enrollment

128 participants

Study Classification

OBSERVATIONAL

Study Start Date

2023-05-03

Study Completion Date

2028-12-31

Brief Summary

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The study aims to investigate the prognostic significance of olfactory function in patients with glioblastoma. We are examining olfactory function at various points during therapy and correlating the results with survival data. In addition, neurocognitive tests will be carried out to correlate the results of olfactory function with the patient's cognitive abilities. Investigations into the quality of life and psychological condition of the patients are also performed. In addition to the cohort of glioblastoma patients, there is a control cohort without tumor disease in which the olfactory testing is also carried out in order to have a comparison.

Detailed Description

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Background: Olfactory impairment is frequent in glioblastoma and is associated with poor overall survival. However, earlier studies were limited by confounding of important predictive factors and the lack of long-term olfactory assessments to evaluate treatment-related neurotoxicity.

Aim: To determine whether olfactory function is an independent prognostic marker for survival, quality of life and neurocognitive outcome in glioblastoma.

Design: Prospective, multicenter cohort study with 64 glioblastoma patients and 64 comparable controls without tumor disease. Patients were stratified by baseline olfactory status, extent of resection, radiologic involvement of olfactory regions,O6-methylguanine DNA methyltransferase (MGMT) promoter methylation, age, and Karnofsky performance status.

Methods: Olfactory function will be serially assessed from diagnosis to treatment using Sniffin' Sticks (identification and threshold tests). Psychosocial assessments, neurocognitive testing and quality of life assessments will be performed at intervals. Coronal T2- and T1-weighted MRI scans will be evaluated independently by blinded neuroradiologists to identify olfactory involvement.

Next-generation sequencing will be used to investigate molecular correlates of hyposmia. As part of a parallel translational study, blood samples will be taken to analyze extracellular vesicles.

Olfactory testing:

In the identification test, 12 sniffin sticks are presented, which the patient has to name using a selection card with four terms each. Both nostrils are tested individually at each visit during the identification test. A correct answer scores one point. A maximum of 12 points is possible.

The threshold test consists of 16 dilution levels. Each level contains one sniffin stick with odor and two blanks. All three sniffin sticks of a dilution level are presented to the patient one after the other with eyes closed. The patient must indicate which of the three sticks contains an odor. Depending on whether the patient gives the correct answer, the three sniffin sticks in the next higher or next lower level are presented next. A maximum of 16 points is possible.

Conditions

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Glioblastoma Multiforme, Adult Glioblastoma or Gliosarcoma Glioblastoma, Adult

Study Design

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Observational Model Type

CASE_CONTROL

Study Time Perspective

PROSPECTIVE

Study Groups

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Newly-diagnosed glioblastoma cohort

olfactory testing (threshold and identification test)

Intervention Type DIAGNOSTIC_TEST

In the identification test, 12 sniffin sticks are presented, which the patient has to name using a selection card with four terms each. Both nostrils are tested individually at each visit during the identification test. A correct answer scores one point. A maximum of 12 points is possible.

The threshold test consists of 16 dilution levels. Each level contains one sniffin stick with odor and two blanks. All three sniffin sticks of a dilution level are presented to the patient one after the other with eyes closed. The patient must indicate which of the three sticks contains an odor. Depending on whether the patient gives the correct answer, the three sniffin sticks in the next higher or next lower level are presented next. A maximum of 16 points is possible.

Control cohort

Control group of patients with non-tumourous (neurological) diseases not primarily associated with an olfactory dysfunction

olfactory testing (threshold and identification test)

Intervention Type DIAGNOSTIC_TEST

In the identification test, 12 sniffin sticks are presented, which the patient has to name using a selection card with four terms each. Both nostrils are tested individually at each visit during the identification test. A correct answer scores one point. A maximum of 12 points is possible.

The threshold test consists of 16 dilution levels. Each level contains one sniffin stick with odor and two blanks. All three sniffin sticks of a dilution level are presented to the patient one after the other with eyes closed. The patient must indicate which of the three sticks contains an odor. Depending on whether the patient gives the correct answer, the three sniffin sticks in the next higher or next lower level are presented next. A maximum of 16 points is possible.

Interventions

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olfactory testing (threshold and identification test)

In the identification test, 12 sniffin sticks are presented, which the patient has to name using a selection card with four terms each. Both nostrils are tested individually at each visit during the identification test. A correct answer scores one point. A maximum of 12 points is possible.

The threshold test consists of 16 dilution levels. Each level contains one sniffin stick with odor and two blanks. All three sniffin sticks of a dilution level are presented to the patient one after the other with eyes closed. The patient must indicate which of the three sticks contains an odor. Depending on whether the patient gives the correct answer, the three sniffin sticks in the next higher or next lower level are presented next. A maximum of 16 points is possible.

Intervention Type DIAGNOSTIC_TEST

Eligibility Criteria

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Inclusion Criteria

* At least 18 years of age
* Newly-diagnosed glioblastoma (IDH wild-type)
* Never received prior chemotherapy
* Never received radiotherapy to the head or neck before
* KPS ≥ 70
* No history of severe head or brain trauma requiring ICU admission or classified as Glasgow Coma Scale grade 3
* No respiratory infection at the time of inclusion
* No significant aphasia

Exclusion Criteria

* Presence of Neurodegenerative diseases (e.g. Parkinson's disease, Alzheimer's disease, Huntington's disease, Korsakoff's syndrome, Pick's disease, Shy-Drager syndrome)
* History of invasive tumors or surgery in the head or neck area, except for surgeries for non-invasive skin tumors (e.g. basal cell carcinomas)
* Permanent olfactory impairment following infections (e.g., influenza, coronavirus)
* Conditions that, in the examiner's judgment, could interfere with the participant's study compliance (e.g., schizophrenia)
* Language barriers likely to interfere with participation or comprehension of study procedures.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Münster University Hospital, Germany

UNKNOWN

Sponsor Role collaborator

Sied Kebir

OTHER

Sponsor Role lead

Responsible Party

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Sied Kebir

PD Dr. med., Head of Clinical Neuro-Oncology

Responsibility Role SPONSOR_INVESTIGATOR

Locations

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University Hospital Essen, Department of Neurology, Division of Clinical Neuro-Oncology

Essen, , Germany

Site Status RECRUITING

Department of Neurosurgery

Münster, , Germany

Site Status RECRUITING

Countries

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Germany

Central Contacts

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Christoph Oster, Dr. med.

Role: CONTACT

+49201-723-82598

Sied Kebir, PD Dr. med.

Role: CONTACT

+49201-723-83133

Facility Contacts

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Christoph Oster, Dr. med.

Role: primary

+49 201 723 82598

Michael Müther, PD Dr. med.

Role: primary

+49 251 83-47472

References

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Hummel T, Sekinger B, Wolf SR, Pauli E, Kobal G. 'Sniffin' sticks': olfactory performance assessed by the combined testing of odor identification, odor discrimination and olfactory threshold. Chem Senses. 1997 Feb;22(1):39-52. doi: 10.1093/chemse/22.1.39.

Reference Type BACKGROUND
PMID: 9056084 (View on PubMed)

Hummel T, Konnerth CG, Rosenheim K, Kobal G. Screening of olfactory function with a four-minute odor identification test: reliability, normative data, and investigations in patients with olfactory loss. Ann Otol Rhinol Laryngol. 2001 Oct;110(10):976-81. doi: 10.1177/000348940111001015.

Reference Type BACKGROUND
PMID: 11642433 (View on PubMed)

Kebir S, Hattingen E, Niessen M, Rauschenbach L, Fimmers R, Hummel T, Schafer N, Lazaridis L, Kleinschnitz C, Herrlinger U, Scheffler B, Glas M. Olfactory function as an independent prognostic factor in glioblastoma. Neurology. 2020 Feb 4;94(5):e529-e537. doi: 10.1212/WNL.0000000000008744. Epub 2019 Dec 12.

Reference Type BACKGROUND
PMID: 31831598 (View on PubMed)

Walker IM, Fullard ME, Morley JF, Duda JE. Olfaction as an early marker of Parkinson's disease and Alzheimer's disease. Handb Clin Neurol. 2021;182:317-329. doi: 10.1016/B978-0-12-819973-2.00030-7.

Reference Type BACKGROUND
PMID: 34266602 (View on PubMed)

Oster C, Matyar A, Schmidt T, Hummel T, Hattingen E, Jokisch M, Jokisch D, Grieger J, Cappello G, Kizina K, Lazaridis L, Ahmadipour Y, Rauschenbach L, Stuschke M, Pottgen C, Guberina N, Tertel T, Giebel B, Dreizner GL, Barbato F, Skoda EM, Scheffler B, Muther M, Herrmann K, Kleinschnitz C, Sure U, Deuschl C, Glas M, Kebir S. Decoding glioblastoma survival: unraveling the prognostic potential of olfactory function in a prospective observational study. Neurol Res Pract. 2025 Jul 24;7(1):51. doi: 10.1186/s42466-025-00410-2.

Reference Type DERIVED
PMID: 40708059 (View on PubMed)

Other Identifiers

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22-10501-BO

Identifier Type: -

Identifier Source: org_study_id

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