Surg-20. usefulness of photodynamic therapy (pdt) with talaporfin sodium for glioblastoma

BACKGROUND Photodynamic therapy (PDT) with talaporfin sodium uses the toxicity of singlet oxygen generated by a reaction between a photosensitizer in tumor cells and light with a specific wavelength. PDT was introduced in our hospital in April 2017. We retrospectively analyzed the glioblastoma (GBM) patients treated with PDT and compared with the patients who did not receive PDT. MATERIAL AND METHODS From April 2015 to March 2023, total 145 patients with GBM were treated in our hospital. Among them, patients of recurrence, IDH mutant, biopsy and no chemo/radiotherapy were excluded. The patients’ characteristics, adverse event, changes of the MR image, recurrence pattern, outcome of the patients were analyzed. In addition, survival time of the patients between the PDT group and the non-PDT group was compared. RESULTS A total of 80 GBM patients were analyzed. Forty-four patients received PDT. 4 patients had adverse event; cyst formation, venous infarction, brain swelling, and delirium. In most of the patients, linear high signals of 5-7 mm on DWI were detected at the surface of the resected cavity and matched the PDT-irradiated area from 1 day after PDT. All hyperintense signal on DWI disappeared in about 30 days without any neurological deterioration. Sixty-seven patients had recurrence (PDT group; 33 cases, non-PDT group; 34 cases). Recurrence pattern of distant/dissemination were significantly increased in the PDT group compared with the non-PDT group. The PDT group tended to have longer survival in both OS (p = 0.08) and PFS(p = 0.07) than the non-PDT group. In multivariate analysis for OS, age and MGMT promotor methylation were significant prognostic factors, but not PDT. CONCLUSION PDT was safety and useful for GBM. However, the PDT group had significantly more distant/disseminated recurrences than the non-PDT group. We need to analyze more cases to clarify efficacy and recurrence patterns.