Postoperative Speech Impairment and Surgical Approach to Posterior Fossa Tumours in Children: A Prospective European Multicentre Study

Background: Brain tumours are the most common childhood tumours. Half of them are in the posterior fossa, where surgical removal is complicated by postoperative speech impairment (POSI) in up to 25% of patients. POSI manifests within days of surgery, while improvement takes weeks or months. The surgical approach to midline tumours, mostly undertaken by transvermian or telovelar routes, has been proposed to influence the risk of POSI. We investigated the risk of developing POSI, the time course of its resolution and its association with surgical approach and other clinical factors.  Methods: 426 children aged 0–17·9 years undergoing primary surgery for a posterior fossa tumour at 26 centres in nine European countries were prospectively included. Speech was classified as either mutism, reduced or habitual at two weeks, two months, and one year after surgery.  Findings: POSI developed in 30% of patients: Mutism in 15% (56/378) a median 1 day after surgery (IQR, 0–2; max 10) and reduced speech in 15% (58/378). In multivariate analysis, POSI was associated with using a telovelar approach (odds ratio (OR), 1·7; 95% CI, 1·03–2·9, p<0·05) compared with other approaches, younger age (OR per year increase in age, 0·90; CI, 0·83–0·96; p<0·01), midline location (OR, 4·1; CI, 1·9–9·6; p<0·001), and histology of medulloblastoma (OR, 2·8; CI, 1·5–5·1; p<0·001) with pilocytic astrocytoma as reference. Transvermian approach was not associated with increased risk of POSI (OR, 0·99; CI, 0·43–2·2). Mutism resolved in 50% of the patients within 13 days of onset; 4% of patients remained mute after 10 months.  Interpretation: Our data suggest that a telovelar surgical approach, midline tumour location, younger age and medulloblastoma histology all increase the risk of speech impairment after posterior fossa tumour surgery. In most patients, POSI resolved within two weeks of surgery.  Trial Registration: Clinicaltrials.gov (NCT02300766). Funding Statement: The Danish Childhood Cancer Foundation (grant no.: 2012-9, 2014-3, 2015-14, 2016-0143, 2018-3653, 2020-6732), The Swedish Childhood Cancer Foundation (PR2012-0106, KP2019-0014), The Brain Tumour Charity (UK), The Danish Cancer Society (R124-A7920-15-S2), King Christian IX and Queen Louise’s anniversary grant, The Danish Capitol Regions Research Fund, Dagmar Marshall foundation and Rigshospitalet's Research Fund in support of oncology purposes, Brainstrust (SCOT). Declaration of Interests: The authors declare no financial, personal, or other conflict of interest. Ethics Approval Statement: In Denmark, the study was approved by the Research Ethics Committees of the Capital Region in Denmark (H-6-2014-002). Informed consent for the study was obtained according to local legislation, separately to the surgical consent.