Surgical management of newly diagnosed glioblastoma in adults: role of cytoreductive surgery

SummaryThirty papers are included in the attached EvidentiaryTable 1. These include 10 prospective studies and twentyretrospective studies. Five of the prospective studies pro-vided Class II data [10, 12, 16, 19, 20] and one of the 20retrospective studies provided Class II data [14]. All butone of these better quality studies support extent ofresection as a factor in improving survival in newly diag-nosed adult patients with malignant glioma. Of these onlythe study of Levin published in 1985 failed to supportextent of resection for glioblastoma, but did demonstrate asurvival advantage in cases of anaplastic astrocytoma. Ofthe remaining retrospective papers reviewed, all providedClass III data. Fourteen of the nineteen provided data thatsupported the concept of cytoreductive surgery in the initialmanagement of malignant glioma. As a result, it followsthat the majority of the reviewed data supports maximalcytoreductive surgery.In addition it is clear that rigorous postoperative imagingand analysis of residual tumor burden is best done by anindependent analyst and that it is indicative of increasedsurvival. Quality of life continues is an important pre andpostoperative consideration and appears to be maintainedfor longer periods of time in the setting of a maximaldebulking operation.Key issues for future investigationThe need for better data either through randomized trial orprospective ‘‘case control’’ methodology is clear fromreviewing the long list of studies that have attempted toaddress the issue of extent of resection and the resultanteffect on survival and quality of life in patients withmalignant glioma. Major advances can be identified sincethe studies in the late 1980s in terms of clarifying thehistopathological diagnosis and in assessing the extent ofresection using neuroimaging as opposed to intraoperativesurgical judgment.Itisclearfromthisreviewthatstudiesdesignedtoaddressthe impact of extent of resection or postoperative tumorburden on clinical outcome must incorporate neuroimagingmethodology that allows accurate and consistent analysis.The role of advanced neuro-imaging in effectingresections in these patients remains an area of investiga-tion. The role of MRI and advanced ultrasound imagingneed to be clarified and expanded to improve the extent andsafety of surgery while balancing cost-effective technologydevelopment.Development of standardized methodologies for resid-ual tumor assessment and investigation into techniques forassessing the residual ‘‘non-enhancing’’ tumor burden areneeded. The study of malignant primary neoplasms withevolving molecular imaging techniques will allow theimpact of residual malignant cells on patient outcome to beevaluated and trigger the continued development ofmolecular based treatment paradigms.The continued development of intra-operative tumormarkers or enhancing agents should greatly assist in sur-gical decision-making and may result in improved extent ofresection without creating new neurological deficit.