MATERIAL and METHODS: This retrospective single-institutional study involved 177 GBM patients diagnosed between 2015 and 2022. Patients with confirmed IDH wild-type GBM were selected to assess the impact of lesion focalities on prognosis. Surgical procedures included gross total resection (GTR), subtotal resection (STR) or biopsy. Radiation therapy (RT) employed the intensitymodulated (IM)RT technique, combined with concurrent temozolomide (TMZ) treatment. Survival analyses and prognostic factors were performed accordingly.

RESULTS: We examined 101 IDH wild-type glioblastoma patients, of whom 78 had unifocal and 23 had multifocal tumors. The median patient age was 60 years, comprising 37% females and 63% males. Surgical approaches included GTR (13%), STR (53%), and biopsy (34%). Positive p53 expression was seen in 65 patients. All patients received TMZ with RT. Adjuvant therapy referral was arranged for 68 patients. Progression occurred in 49% (38 unifocal, 11 multifocal cases). PFS analysis showed no significant difference between unifocal and multifocal patients. OS analysis also showed no significant difference. Univariate analysis revealed PFS factors: focalization, p53 expression, hypofractionated RT. For OS, adjuvant TMZ usage was influential. Extent of resection impacted OS-STR had 3.47-fold higher risk than GTR.

CONCLUSION: This study sheds light on the management of multifocal glioblastoma, providing insights into treatment strategies and survival outcomes. Despite challenges, optimal management approaches are crucial for improving patient prognosis and quality of life. Keywords : Glioblastoma, Multifocal GBM, Radiotherapy, Temozolamide