Delay in diagnosing patients with right-sided glioblastoma induced by hemispheric-specific clinical presentation

Cognitive functions are differentially represented in brain hemispheres. Aphasia is an "easy to recognize" symptom of diseases affecting the left side. In contrast, lesions in the right hemisphere cause subtle neuropsychological deficits such as neglect and anosognosia. We evaluated whether right-sided malignant brain tumors are on average larger at the time of first diagnosis as compared to left-sided tumors, and extrapolated the delay in diagnosing right-sided tumors compared to the left side.

All first-ever diagnosed glioblastoma (GBM) patients between 2005 and 2012 were identified using our hospital-based prospective research registry. Baseline data, information on initial clinical presentation and imaging findings (including tumor volume) were collected. Extrapolation of time since tumor initiation was based on an established gompertzian growth model.

We included 173 patients. Mean age of the study population was 58 ± 13 years. Tumors located in the right hemisphere (n = 96) were larger as compared to tumors located in the left hemisphere (n = 77) (median 36.4 mL [interquartile range 13.0-56.0; minimum 0.2, maximum 140.0] vs. 17.2 mL [7.7-45.1 mL; 0.4, 105.2]; p = 0.011). Right-sided tumors grew longer than left-sided tumors (378 ± 95 days vs. 341 ± 74 days; p = 0.006). Initial neuropsychological symptoms differed depending on the affected hemisphere.

Right-hemispheric symptoms appear to be less clinically conspicuous resulting in a delayed diagnosis of GBM, which might be improved by raising awareness for the corresponding neuropsychological deficits. Whether our findings have prognostic implications needs to be evaluated in future studies.