cancers Article Interstitial Photodynamic Therapy Using 5-ALA for Malignant Glioma Recurrences Stefanie Lietke 1,2,† , Michael Schmutzer 1,2,† , Christoph Schwartz 1,3, Jonathan Weller 1,2 , Sebastian Siller 1,2 , Maximilian Aumiller 4,5 , Christian Heckl 4,5 , Robert Forbrig 6, Maximilian Niyazi 2,7, Rupert Egensperger 8, Herbert Stepp 4,5 , Ronald Sroka 4,5 , Jörg-Christian Tonn 1,2, Adrian Rühm 4,5,‡ and Niklas Thon 1,2,*,‡ 1 Department of Neurosurgery, University Hospital, LMU Munich, 81377 Munich, Germany 2 German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany 3 Department of Neurosurgery, University Hospital Salzburg, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria 4 Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, 81377 Munich, Germany 5 Department of Urology, University Hospital, LMU Munich, 81377 Munich, Germany 6 Institute for Clinical Neuroradiology, University Hospital, LMU Munich, 81377 Munich, Germany 7 Department of Radiation Oncology, University Hospital, LMU Munich, 81377 Munich, Germany 8 Center for Neuropathology and Prion Research, University Hospital, LMU Munich, 81377 Munich, Germany * Correspondence:
[email protected]; Tel.: +49-89-4400-0 † Both authors contributed equally. ‡ This study is guided by AR and NT equally thus both serve as shared last authors. Citation: Lietke, S.; Schmutzer, M.; Schwartz, C.; Weller, J.; Siller, S.; Simple Summary: Malignant glioma has a poor prognosis, especially in recurrent situations. Intersti- Aumiller, M.; Heckl, C.; Forbrig, R.; tial photodynamic therapy (iPDT) uses light delivered by implanted light-diffusing fibers to activate Niyazi, M.; Egensperger, R.; et al. a photosensitizing agent to induce tumor cell death. This study examined iPDT for the treatment Interstitial Photodynamic Therapy of malignant glioma recurrences.