Isotope (FMISO) production is no longer available in our country.

The aim of this study is to assess, with 18F-FMISO PET, hypoxia in high grade gliomas and changes by spinal cord stimulation in a subset of patients. Additionally, the potential correlation with pathological, imaging and clinical parameters will be analyzed.

Tumour ischaemia-hypoxia decreases the efficacy of radio-chemotherapy. Polarographic probe (and some 18F-FMISO-PET) studies have demonstrated prognostic value. Additionally hypoxia modification may increase survival. However, in high grade gliomas (HGG) there are not well established methods to evaluate and modify tumor hypoxia. We have previously described how spinal cord stimulation (SCS) can modify oxygenation, blood flow and metabolism in malignant gliomas. The aim of this study is to assess with 18F-FMISO PET: hypoxia in HGG and changes by spinal cord stimulation in a subset of patients. Additionally, the potential correlation with pathological, imaging and clinical parameters will be analyzed.

18F-FMISO PET will be performed in 20 patients with diagnosis of HGG: after surgery/biopsy and before radical treatment with 3D radiotherapy and temozolomide. A subset of 10 patients undergo two studies with 18F- FMISO-PET (one with SCS "off" and one with SCS "on"). In these patients, SCS will be connected from 1 hour before to 1 hour after each radiotherapy session, and in the day-time during the days of adjuvant temozolomide.

18F-FMISO PET results will not be taking into account for patient management. Patients will be followed at least until the end of adjuvant temozolomide (6 months after the end of concurrent radiochemotherapy).

Inclusion Criteria:

• Patients with pathologically confirmed (first presentation or relapsed) high grade glioma (Grade III or Grade IV according WHO criteria) proposed for radical treatment with 3D radiotherapy and temozolomide.
• Patients 18-75 years old.
• Karnofsky >= 60% and ECOG =< 2.
• Signed informed consent.

Exclusion Criteria:

• Clinical or psychological contraindications to fly (if 18F-FMISO-PET is realized in Madrid) or to SCS-placement (only for this subset).
• Pregnant or breastfeeding women and women of fertile age who are not using a safe contraceptive method or do not intend to use one during the trial. Safe contraceptive methods are oral or parenteral contraceptive treatments or barrier methods: masculine or feminine condom, diaphragm and/or intrauterine device (IUD) or withdrawal over the course of the study.
• Serious co-existing or concurrent illness, including any of the following: uncontrolled or severe infection, heart, liver or kidney disease
• Lung thromboembolism.
• Another malignancy in the last 5 years other than basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix.
• Patients with life expectancy <3 months.
• Patients with any of the following: creatinine > 2 mg/dl, neutrophils <1.5 * 10^9/L, platelets <100 * 10^9/L or hemoglobin <8.5 g/dL.
• Contraindications to receive radiotherapy or chemotherapy Clinical or psychological contraindications for placement of spinal cord stimulation devices (only for that specific subset of patients).
• Patients who are unable or unwilling to meet the protocol study.
• Patients who do not meet all the inclusion criteria.