NCT06954636

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

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 128 (estimated)
• Sponsor: Sied Kebir · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

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

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

• Glioblastoma Multiforme, Adult
• Glioblastoma or Gliosarcoma
• Glioblastoma, Adult

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	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.

Timeline

• Start date: 2023-05-03
• Primary completion: 2027-12-31
• Completion: 2028-12-31
• First posted: 2025-05-01
• Last updated: 2025-07-08

Locations

2 sites across 1 country: Germany