The use of homeopathy is remarkably popular. Popularity, however, is not an arbiter in a scientific discourse. In fact, the assumptions underlying homeopathy violate fundamental laws of nature. Homeopathy does not have any explanatory power and fails other criteria established for a scientific approach. Two large-scale efforts have recently documented that in spite of a plethora of clinical trials there is no evidence that homeopathic remedies have any therapeutic effect, which goes beyond that of a placebo. Relaxed regulations and lack of scientific literacy and of health education allow for continuous thriving of homeopathy. While the tide may be changing on the regulatory side, health education of the general public is presumably more important to support informed decision making by patients. Otherwise, the responsible patient, who is posited to decide on the medical choices, remains a convenient legal fiction.

Background: In the next decades, the incidence of patients with glioblastoma (GBM) will increase due to the growth of the elderly population. Fluorescence-guided resection using 5-aminolevulinic acid (5-ALA) is widely applied to achieve maximal safe resection of GBM and is identified as a novel intraoperative marker for diagnostic tissue during biopsies. However, detailed analyses of the use of 5-ALA in resections as well as biopsies in a large elderly cohort are still missing. The aim of this study was thus to investigate the efficacy, outcome, and safety of surgically- treated GBM in the 5-ALA era in a large elderly cohort. Methods: All GBM patients aged 65 years or older who underwent neurosurgical intervention between 2007 and 2019 were included. Data on 5-ALA application, intraoperative fluorescence status, and 5-ALA-related side effects were derived from our databank. In the case of resection, the tumor resectability and the extent of resection were determined. Potential prognostic parameters relevant for overall survival were analyzed. Results: 272 GBM patients with a median age of 71 years were included. Intraoperative 5-ALA fluorescence was applied in most neurosurgical procedures (n = 255/272, 88%) and visible fluorescence was detected in most cases (n = 252/255, 99%). In biopsies, 5-ALA was capable of visualizing tumor tissue by visible fluorescence in all but one case (n = 91/92, 99%). 5-ALA administration did not result in any severe side effects. Regarding patient outcome, smaller preoperative tumor volume (<22.75 cm3), gross total resection, single lesions, improved postoperative neurological status, and concomitant radio-chemotherapy showed a significantly longer overall survival. Conclusions: Our data of this large elderly cohort demonstrate the clinical utility and safety of 5-ALA fluorescence in GBM for improved tumor visualization in both resections as well as biopsies. Therefore, we recommend the use of 5-ALA not only in resections, but also in open/stereotactic biopsies to optimize the neurosurgical management of elderly GBM patients.

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OBJECTIVE Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) is nowadays widely applied for improved resection of glioblastomas (GBMs). Initially, pretreatment with dexamethasone was considered to be essential for optimal fluorescence effect. However, recent studies reported comparably high rates of visible fluorescence in GBMs despite absence of dexamethasone pretreatment. Recently, the authors proposed fluorescence lifetime imaging (FLIM) for the quantitative analysis of 5-ALA–induced protoporphyrin IX (PpIX) accumulation. The aim of this study was thus to investigate the influence of dexamethasone on visible fluorescence and quantitative PpIX accumulation. METHODS The authors prospectively analyzed the presence of visible fluorescence during surgery in a cohort of patients with GBMs. In this study, patients received dexamethasone preoperatively only if clinically indicated. One representative tumor sample was collected from each GBM, and PpIX accumulation was analyzed ex vivo by FLIM. The visible fluorescence status and mean FLIM values were correlated with preoperative intake of dexamethasone. RESULTS In total, two subgroups with (n = 27) and without (n = 20) pretreatment with dexamethasone were analyzed. All patients showed visible fluorescence independent from preoperative dexamethasone intake. Furthermore, the authors did not find a statistically significant difference in the mean FLIM values between patients with and without dexamethasone pretreatment (p = 0.097). CONCLUSIONS In this first study to date, the authors found no significant influence of dexamethasone pretreatment on either visible 5-ALA fluorescence during GBM surgery or PpIX accumulation based on FLIM. According to these preliminary data, the authors recommend administering dexamethasone prior to fluorescence-guided surgery of GBMs only when clinically indicated.