gms | German Medical Science

Objective: Placement of carmustin wafers (Gliadel) as a local chemotherapeutic depot has become a common practice in glioblastoma (GBM) resection. Different studies have reported a survival benefit, but the results vary widely. Those studies include a lot of clinical parameters but do not define the local circumstances of wafer placement. In particular, the lack of information about the amount of used wafers may mask dose-dependent effects. Also the surface of the resection-cavity as volume of carmustin distribution is not well defined. The aim of our investigation is to figure out intraoperative parameters, influencing the individual survival benefit.

Method: A retrospective analysis of 24 patients with a single, supratentorial GBM treated with total or subtotal resection and additional Gliadel wafer placement during the operative procedure in a 4-year period. 30% of the patients received primary Gliadel placement, 70% during the secondary resection. All patients had standard postoperative treatment following the stupp protocol after primary resection and chemotherapy after secondary resection. In all cases we performed preoperative tumour-volumetry and early postoperative MRI with quantification of the residual tumour mass. The amount of carmustin wafers used, the overall Survival (OS), postoperative survival (POS) and progression-free survival (PFS) were evaluated.

Results: Different correlations could be observed, mainly in the secondary resection group: Total resection is superior to subtotal resection, longer POS is not correlated with the total amount of inserted carmustin but with amount of carmustin in relation to the volume of the resection-cavity. Patients treated with a carmustin concentration above 5 mg/cm² have a longer although no statistically significant POS than those treated with a concentration under 5 mg/cm². An increased rate of complications could not be observed in patients with high carmustin concentration.

Conclusions: Our small patient group left the impression of a dose-dependent effect of Gliadel. A higher concentration of carmustin in the postoperative resection cavity results in longer POS. Perhaps one should limit the use of Gliadel in future to a smaller subgroup of GBM patients with a special tumour cavity configuration allowing higher carmustin concentrations to access better Gliadel effects. Surely, there is a pressing necessity for additional studies about the effectiveness of Gliadel in GBM surgery with respect to the emplacement conditions.