Impact of Laterality in Glioblastoma Patients

Aims: Hemispheric dominance for neurological tasks is a distinct attribute of the brain. Its role for GBM patients in determining surgical morbidity and outcome is vague. We analyzed all GBM cases treated at our institution in the past 10 years and assessed whether there is a difference regarding clinical characteristics, extent of resection, functional outcome and survival in relation to tumor lateralization.

Methods: All adult patients diagnosed of a supratentorial GBM and treated at our hospital between 2006 and 2016 were analyzed. Cases not unequivocally allocable to one hemisphere or with incomplete documentation were excluded.

Results: 235 patients were included. Uniform tumor distribution to both hemispheres was documented (48.5% in left (LH) and 51.5% in right hemisphere (RH)).RH were of slightly larger volumes (30.2 LH versus 35.9 cm3 RH, p = 0.0913) and presented more frequently in the frontal lobe (29.8 LH versus 43.0% RH, p = 0.0424).Language deficits were more frequent in LH (63.2 LH versus 10.0% RH, p < 0.0001),as with memory deficits (34.2 LH versus 22.5% RH, p = 0.0587) and opposed to limb paresis (29.8 LH versus 51.7% RH, p = 0.0009) and neglect (5.3 LH versus 12.5% RH, p = 0.0672).KPS at presentation showed no significant difference between groups (81.2 LH and 82.6 RH, p = 0.4126). However, KPS decline at 12mt was greater in LH (50.5 LH versus 40.7 RH, p = 0.05).Significantly more LH suffered from dysphasia (transient and permanent) after resection (54.6 LH versus 4.4% RH, p < 0.0001),while no difference was seen for paresis (36.0 LH versus 35.3% RH, p = 0.9299).Treatment modalities (rate of biopsy, resection, chemo- and radiotherapy) did not differ for LH and RH and overall EOR was comparable (90.9 LH and 93.7% RH, p = 0.2380).Remarkably,100% EOR was achieved significantly more often in RH (37.7 LH versus 64.8% RH p = 0.0028).While OS did not significantly differ between groups, PFS was significantly shorter in LH (32 LH versus 44w RH, p = 0.0225).

Conclusions: Our study confirms previous reports stating similar OS between LH and RH GBMs. However, LH patients had a significantly shorter clinical and radiological PFS and a pronounced decline in functional abilities. This observation might partly be attributed to the less often achieved 100% EOR. The impact of language dysfunctions on QOL of GMB patients and thus its influence on therapeutic decisions is an important parameter and requires further investigations.

No conflict of interest has been declared by the author(s).