The multicenter, randomized phase II study “GlioCave” will evaluate the efficacy of adjuvant radiation therapy to the resection cavity after complete resection of recurrent glioblastoma. Radiation therapy of the resection cavity with 36 à 3 Gy or 46 à 2 Gy will be compared with a control. Chemotherapy is not part of the study protocol and may be administered in either arm, depending on the recommendation of the treating neuro-oncologist.

Inclusion criteria:

• Supratentorial recurrence of glioblastoma
• Previous standard therapy of primary tumor
• Complete resection of contrast enhancement on post-operative MRI
• Age of at least 18 years
• Karnofsky status of at least 60%
• Adequate contraception
• Ability to understand the character and potential individual consequences of study participation
• Written informed consent

Exclusion Criteria:

• Distant multifocal glioblastoma or gliomatosis cerebri
• Less than 6 months since previous radiation therapy
• Previous re-radiation or pre-treatment with interstitial brachytherapy
• Withdrawal of consent for study participation
• Pronounced side effects from previous therapy
• Active malignancy within the last 5 years (excluding carcinoma in situ of the cervix, basal cell carcinoma, squamous cell carcinoma of the skin)
• Pregnant or breastfeeding women
• Participation in another clinical trial

Primary endpoint: progression-free survival

Secondary endpoints: Overall survival, toxicity, safety, quality of life, neurocognitive function (at selected centers), evidence of response on early MRI