BACKGROUND: Glioblastoma (GBM) is characterized by marked proliferation, major infiltration, and poor prognosis. Despite current treatments, including surgery, radiation oncology, and chemotherapy, the overall median survival is 15 mo and the progression-free survival is 7 to 8 mo. Because of systematic relapse of the tumor, the improvement of local control remains an issue. In this context, photodynamic therapy (PDT) may offer a new treatment modality for GBM. OBJECTIVE: To assess the feasibility of intraoperative PDT early after surgical resection of GBM without unacceptable and unexpected toxicities. METHODS: The INDYGO clinical trial (INtraoperative photoDYnamic Therapy for GliOblastomas) treatment will be carried out in addition to the current standard of care (SOC) of glioblastoma: maximum resection surgery followed by concomitant radio-chemotherapy and adjuvant chemotherapy. PDT treatment will be delivered during surgery early, after the fluorescence-guided resection. Immunological responses and biomarkers will also be investigated during the follow-up. A total of 10 patients will be recruited during this study. EXPECTED OUTCOMES: Clinical follow-up after the SOC with PDT is expected to be similar (no significant difference) to the SOC alone. DISCUSSION: This INDYGO trial assesses the feasibility of intraoperative 5-aminolevulinic acid PDT, a novel seamless approach to treat GBM. The technology is easily embeddable within the reference treatment at a low-incremental cost. The safety of this new treatment modality is a preliminary requirement before a multicenter randomized clinical trial can be further conducted to assess local control improvement by treating infiltrating and nonresected GBM cells.

Aim: Photodynamic therapy (PDT) appears to be a valuable new treatment modality for cancer therapy. Studies have reported successful application of PDT for glioblastoma. Here, we introduce a new device dedicated to intraoperative PDT delivered early after fluoro-guided resection combined with a transfer function that determines the treatment time based on the size of the surgical resection cavity. Materials & methods: First, we describe the device, which is composed of a trocar, a balloon filled with a diffusing solution, and a fiber guide in which a cylindrical light diffuser is inserted. Ex vivo experiments were performed to measure the fluence rate inside biological tissues. A calibration factor was defined to convert power measurements into fluence rate values. Calf brains were used to simulate light propagation in human brain tissue, and the photosensitizer administration effect on optical properties was discussed. The temperature elevation during illumination was evaluated. Results: Light power was ...