Standardized intraoperative 5-ALA photodynamic therapy for newly diagnosed glioblastoma patients: a preliminary analysis of the INDYGO clinical trial

A high-entropy coordination cage featuring an Au-porphyrin metalloligand for the photodynamic therapy of liver cancer

We report a Pd-based hexagonal prismatic coordination cage of Pd-TMPP(Au) featuring a highly entropic ligand combination, viz. H2TMPP, TMPP(Pd), and TMPP(Au) metalloligands to yield double-arrow-shaped polycrystals. Pd-TMPP(Au) exhibits concentration-dependent cytotoxicity against hepatocellular carcinoma cell lines HuH-7, Hep-G2, and PLC/PRF/5, which is augmented by light irradiation.

Imaging treatment efficacy of repeated photodynamic therapy in glioblastoma using chemical exchange transfer saturation MRI

PURPOSE

To observe the tumor responses during photodynamic therapy in a murine glioblastoma model using chemical exchange saturation transfer (CEST) MRI and to compare the treatment effectiveness between single photodynamic therapy (sPDT) and repeated PDT (rePDT).

METHODS

After tumor cell implantation in NSG mouse brain (n = 27), mice were subjected to four PDT sessions (rePDT), sPDT after the administration of 5-aminolevulinic acid 6 h before each session, and a non-PDT session (control). A 630-nm LED light was used to effectuate PDT. After 24 h for each PDT session, T2-weighted and CEST MRI were performed over 7 days.

RESULTS

We observed that rePDT resulted in a continuous suppression of tumors according to T2-weighted images; thus, the tumor volume was the smallest among three groups on Day 7. Both CEST contrasts at 3.5 ppm (amide proton transfer, APT) and- $$ - $$ 3.5 ppm (relayed nuclear Overhauser enhancement, rNOE) in the rePDT group were significantly lower (p < 0.05) than those in the control group starting from Day 5, which corresponds to lower protein and cellularity in tumors in the rePDT group, respectively. CEST contrast decreased by 17.9% at 3.5 ppm and 11.3% at- $$ - $$ 3.5 ppm for rePDT group. This was validated by histology, where we observed moderate correlations between APT with cell proliferation (R = 0.730, p < 0.01) and cell apoptosis (R = 0.715, p < 0.05) and moderate correlation between rNOE with cellularity (R = 0.796, p < 0.01).

CONCLUSIONS

rePDT has a better effect in tumor growth suppression when compared with sPDT, and CEST could be a robust and noninvasive mean to assess the molecular changes related to treatment efficacy.

Three Decades of Photodynamic Therapy for Glioblastoma: A Comprehensive Scientometric Analysis

BACKGROUND

Photodynamic therapy (PDT) has emerged as a promising adjunctive treatment for glioblastoma (GBM), yet a comprehensive bibliometric analysis of this field is lacking. This study explores research trends, major contributors, and hotspots in PDT for GBM to provide an integrated overview of its development.

METHODS

Literature from 1993 to 2024 was retrieved from the Web of Science Core Collection. Bibliometric tools, including CiteSpace, analyzed publication trends, collaborations, and keyword co-occurrence to identify influential authors, institutions, and journals.

RESULTS

A total of 799 publications showed a growing research interest, peaking in 2022. The United States and China were leading contributors, with prominent institutions like the University of California System and Centre National de la Recherche Scientifique. Influential figures, such as Jiro Akimoto and Walter Stummer, advanced clinical applications and fluorescence-guided techniques. Early studies of PDT for GBM have focused on evaluating its efficacy and potential side effects, while recent research has transitioned toward innovative strategies like targeted drug delivery, nanotechnology, and combination therapies. However, the similarities between early and recent studies are in the search for safe and reliable photosensitizers. Keyword analysis highlighted "5-aminolevulinic acid", "in vitro", and "polyethylene glycol compounds" as key areas, while timeline analysis revealed shifts from foundational photosensitizer research to approaches addressing tumor heterogeneity and resistance.

CONCLUSIONS

This study provides a systematic overview of PDT research for GBM, spotlighting breakthroughs and collaborative networks. The findings emphasize the importance of innovation and clinical translation to fully realize PDT's potential in GBM therapy.

Toward the Treatment of Glioblastoma Tumors Using Photoactivated Chemotherapy: In Vitro Evaluation of Efficacy and Safety

Glioblastoma multiforme (GBM) is highly aggressive, necessitating new therapies. Photoactivated chemotherapy (PACT) offers a promising approach by activating prodrugs with visible light at the tumor site. This study evaluated the anticancer activity of ruthenium-based PACT compounds in U-87MG glioblastoma cells and their safety in SH-SY5Y neuron-like cells. The compound [3](PF6)2 showed promising light-activated anticancer effects in U-87MG cells, while [1](PF6)2 was inactive, and [2](PF6)2 was nonactivated. Interestingly, in SH-SY5Y cells, light-activated [3](PF6)2 increased cell proliferation, similar to donepezil, without causing cell death. Increased Ca2+ uptake was observed, possibly via interaction with the AMPA receptor, as suggested by docking studies. These findings suggest ruthenium-based PACT compounds may serve as potential treatments for GBM, effectively attacking cancer cells while preserving healthy neuronal cells.

Innovations in intraoperative therapies in neurosurgical oncology: a narrative review

PURPOSE

High-grade gliomas (HGG) represent the most aggressive primary brain tumors in adults, characterized by high recurrence rates due to incomplete resection. This review explores the effectiveness of emerging intraoperative therapies that may extend survival by targeting residual tumor cells. The main research question addressed is: What recent intraoperative techniques show promise for complementing surgical resection in HGG treatment?

METHODS

A comprehensive literature review was conducted, examining recent studies on intraoperative therapeutic modalities that support surgical resection of HGG. Techniques reviewed include laser interstitial thermal therapy (LITT), intraoperative brachytherapy, photodynamic therapy (PDT), sonodynamic therapy (SDT), and focused ultrasound (FUS). Each modality was evaluated based on clinical application, evidence of effectiveness, and potential for integration into standard HGG treatment protocols.

RESULTS

Findings indicate that these therapies offer distinct mechanisms to target residual tumor cells: LITT provides localized thermal ablation; intraoperative brachytherapy delivers sustained radiation; PDT and SDT activate cytotoxic agents in tumor cells; and FUS enables precise energy delivery. Each method has shown varying levels of clinical success, with PDT and LITT currently more widely implemented, while SDT and FUS are promising but under investigation.

CONCLUSION

Intraoperative therapies hold potential to improve surgical outcomes for HGG by reducing residual tumor burden. While further clinical studies are needed to optimize these techniques, early evidence supports their potential to enhance the effectiveness of surgical resection and improve patient survival in HGG management.

Red light-activated depletion of drug-refractory glioblastoma stem cells and chemosensitization of an acquired-resistant mesenchymal phenotype

Glioblastoma stem cells (GSCs) are potent tumor initiators resistant to radiochemotherapy, and this subpopulation is hypothesized to re-populate the tumor milieu due to selection following conventional therapies. Here, we show that 5-aminolevulinic acid (ALA) treatment-a pro-fluorophore used for fluorescence-guided cancer surgery-leads to elevated levels of fluorophore conversion in patient-derived GSC cultures, and subsequent red light-activation induces apoptosis in both intrinsically temozolomide chemotherapy-sensitive and -resistant GSC phenotypes. Red light irradiation of ALA-treated cultures also exhibits the ability to target mesenchymal GSCs (Mes-GSCs) with induced temozolomide resistance. Furthermore, sub-lethal light doses restore Mes-GSC sensitivity to temozolomide, abrogating GSC-acquired chemoresistance. These results suggest that ALA is not only useful for fluorescence-guided glioblastoma tumor resection, but that it also facilitates a GSC drug-resistance agnostic, red light-activated modality to mop up the surgical margins and prime subsequent chemotherapy.

Smart molecular designs and applications of activatable organic photosensitizers

Photodynamic therapy (PDT) - which combines light, oxygen and photosensitizers (PS) to generate reactive oxygen species - has emerged as an effective approach for targeted ablation of pathogenic cells with reduced risk of inducing resistance. Some organic PS are now being applied for PDT in the clinic or undergoing evaluation in clinical trials. A limitation of the first-generation organic PS was their potential off-target toxicity. This shortcoming prompted the design of constructs that can be activated by the presence of specific biomolecules - from small biomolecules to large enzymes - in the target cells. Here, we review advances in the design and synthesis of activatable organic PS and their contribution to PDT in the past decade. Important areas of research include novel synthetic methodologies to engineer smart PS with tuneable singlet oxygen generation, their integration into larger constructs such as bioconjugates, and finally, representative examples of their translational potential as antimicrobial and anticancer therapies.

5-Aminolevulinic acid-mediated photodynamic therapy in combination with kinase inhibitor lapatinib enhances glioblastoma cell death

5-Aminolevulinic acid (ALA) is an intraoperative imaging agent approved for protoporphyrin IX (PpIX) fluorescence-guided resection of glioblastoma (GBM). It is currently under clinical evaluation for photodynamic therapy (PDT) after the completion of GBM surgery. We previously showed that lapatinib, a clinical kinase inhibitor of epidermal growth factor receptor 1 & 2 (EGFR and HER2), enhanced PpIX fluorescence in a panel of GBM cell lines by blocking ABCG2 (ATP-binding cassette super-family G member 2)-mediated PpIX efflux, which suggests its potential for improving ALA for GBM surgery and PDT. Here we show that lapatinib enhanced PDT-induced cytotoxicity by promoting GBM cell death with the induction of apoptosis followed by necrosis. While the induction of tumor cell apoptosis was massive and rapid in the H4 cell line with no detectable Bcl-2 and a low level of Bcl-xL, it was delayed and much less in extent in A172, U-87 and U-118 cell lines with higher levels of pro-survival Bcl-2 family proteins. Lapatinib treatment alone neither reduced GBM cell viability nor had any significant effect on EGFR downstream signaling. Its enhancement of ALA-PDT was largely due to the increase of intracellular PpIX particularly in the mitochondria, resulting in the activation of mitochondria-mediated apoptosis in H4 cells. Our present study demonstrates that lapatinib inhibits ABCG2-mediated PpIX efflux and sensitizes GBM cells to ALA-PDT by inducing tumor cell death.

Noninvasive Ultra Low Intensity Light Photodynamic Treatment of Glioblastoma with Drug Augmentation: LoGlo PDT Regimen

This paper presents the basis for LoGlo PDT, a new treatment for glioblastoma. Glioblastoma is currently treated with maximal safe resection, temozolomide, and ionizing irradiation. Mortality in 2024 remains over 80% within several years from diagnosis. Oral 5-aminolevulinic acid (5-ALA) is an FDA/EMA approved drug that is selectively taken up by malignant cells, including by glioblastoma. In photodynamic treatment of glioblastoma, intense intraoperative light causes glioblastoma tissue that has taken up 5-ALA to generate cytotoxic reactive oxygen species. The requirement for intense light flux has restricted photodynamic treatment to a single one-hour intraoperative session. We analyze here published data showing that external light, illuminating the entire intact scalp, can attain low μW/cm2 flux several cm into intact brain that would be sufficient to mediate 5-ALA photodynamic treatment of glioblastoma if the light and 5-ALA are delivered continuously over 24 h. At the core of LoGlo PDT regimen is the dataset showing that, for a given fluence, as the duration of PDT light delivery goes down, light intensity (flux) delivered must go up to achieve the same glioblastoma cell cytotoxicity as would a weaker light (lower flux) delivered over a longer time. Thus, a repetitive, noninvasive PDT of glioblastoma using an external light source may be possible. We analyze 5-ALA cellular physiology to show that three non-oncology drugs, ciprofloxacin, deferiprone, and telmisartan, can be repurposed to increase light energy capture after 5-ALA, thereby increasing photodynamic treatment's glioblastoma cell cytotoxicity. The LoGlo PDT approach uses both drug augmentation and prolonged ultra-low noninvasive transcranial light delivery for a repetitive, noninvasive 5-ALA photodynamic treatment of glioblastoma.

Enlightening the invisible: Applications, limits and perspectives of intraoperative fluorescence in neurosurgery

Introduction

The introduction of intraoperative fluorophores represented a significant advancement in neurosurgical practice. Nowadays they found different applications: in oncology to improve the visualization of tumoral tissue and optimize resection rates and in vascular neurosurgery to assess the exclusion of vascular malformations or the permeability of bypasses, with real-time intraoperative evaluations.

Research question

A comprehensive knowledge of how fluorophores work is crucial to maximize their benefits and to incorporate them into daily neurosurgical practice. We would like to revise here their applications and clinical relevance.

Material and methods

A focused literature review of relevant articles dealing with the versatile applications of fluorophores in neurosurgery was performed.

Results

The fundamental mechanisms of action of intraoperative fluorophores are enlightened, examining their interactions with target tissues and the principles driving fluorescence-guided surgery. The clinical applications of the principal fluorophores, namely fluorescein sodium, 5-ALA and indocyanine green, are detailed, in regards to the management of vascular malformations, brain tumors and pathologies treated through endoscopic endonasal approaches.

Discussion and conclusion

Future perspective dealing with the development of new technologies or of new molecules are discussed. By critically assessing the efficacy and applications of the different fluorophores, as well as charting their potential future uses, this paper seeks to guide clinicians in their practice and provide insights for driving innovation and progress in fluorescence-based surgery and research.

Photodynamic opening of the blood-brain barrier affects meningeal lymphatics and the brain's drainage in healthy male mice

Here, we present the new vascular effects of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA). PDT with 5-ALA induces a leakage of both the meningeal and cerebral blood vessels. The extravasation of photo-excited 5-ALA from the leaky blood vessels into the meninges causes photo-damage of the meningeal lymphatics (MLVs) leading to a dramatic reducing the MLV network and brain's drainage. The PDT-induced impairment of lymphatic regulation of brain's drainage can lead to excessive accumulation of fluids in brain tissues, which is important to consider in the PDT therapy for brain diseases as s possible side effect of PDT with 5-ALA.

Cytocidal Effects of Interstitial Photodynamic Therapy Using Talaporfin Sodium and a Semiconductor Laser in a Rat Intracerebral Glioma Model

This preclinical study was conducted to investigate the efficacy of interstitial PDT (i-PDT) for malignant gliomas arising deep within the brain, which are difficult to remove. C6 glioma cells were implanted into the basal ganglia of rats, and 3 weeks later, the second-generation photosensitizer talaporfin sodium (TPS) was administered intraperitoneally. Ninety minutes after administration, a prototype fine plastic optical fiber was punctured into the tumor tissue, and semiconductor laser light was irradiated into the tumor from a 2-mm cylindrical light-emitting source under various conditions. The brain was removed 24 h after the i-PDT and analyzed pathologically. The optical fiber was able to puncture the tumor center in all cases, enabling i-PDT to be performed. Histological analysis showed that tumor necrosis was induced in areas close to the light source, correlating with the irradiation energy dose, whereas apoptosis was induced at some distance from the light source. Irradiation using high energy levels resulted in tissue swelling from strong tumor necrosis, and irradiation at 75 J/cm2 was most suitable for inducing apoptosis. An experimental system of i-PDT using TPS was established using malignant glioma cells transplanted into the rat brain. Tumor cell death, which correlated with the light propagation, was induced in tumor tissue.

Intraoperative Resection Guidance and Rapid Pathological Diagnosis of Osteosarcoma using B7H3 Targeted Probe under NIR-II Fluorescence Imaging

Complete removal of all tumor tissue with a wide surgical margin is essential for the treatment of osteosarcoma (OS). However, it's difficult, sometimes impossible, to achieve due to the invisible small satellite lesions and blurry tumor boundaries. Besides, intraoperative frozen-section analysis of resection margins of OS is often restricted by the hard tissues around OS, which makes it impossible to know whether a negative margin is achieved. Any unresected small tumor residuals will lead to local recurrence and worse prognosis. Herein, based on the high expression of B7H3 in OS, a targeted probe B7H3-IRDye800CW is synthesized by conjugating anti-B7H3 antibody and IRDye800CW. B7H3-IRDye800CW can accurately label OS areas after intravenous administration, thereby helping surgeons identify and resect residual OS lesions (<2 mm) and lung metastatic lesions. The tumor-background ratio reaches 4.42 ± 1.77 at day 3. After incubating fresh human OS specimen with B7H3-IRDye800CW, it can specifically label the OS area and even the microinvasion area (confirmed by hematoxylin-eosin [HE] staining). The probe labeled area is consistent with the tumor area shown by magnetic resonance imaging and complete HE staining of the specimen. In summary, B7H3-IRDye800CW has translational potential in intraoperative resection guidance and rapid pathological diagnosis of OS.

An innovative approach to detect circulating tumor cells

In cancer research, circulating tumor cells (CTCs) were identified as the main drivers of metastasis. They are vital for early detection and prevention of metastasis during cancer treatment. Even though continuous progress in research offers more and more tools to combat cancer, we still lack a proper arsenal of therapeutics. Especially in tumors with close to no targeting options, like triple-negative breast cancer, early detection is often the main difference between successful and failed therapy. When such tumors are detected too late, they may have already produced plenty of CTCs, likely causing metastasis, which is the primary reason for tumor-associated deaths. Detecting those CTCs early on could substantially impact therapy outcomes and the 5-year survival rate. In our study, we developed and evaluated a reliable and affordable CTC screening method based on flow cytometry and 5-aminolevulinic acid (5-ALA) staining. We successfully established a circulation model for 5-ALA and CTCs research and demonstrated that the method can detect an average of 11 ± 3.3 CTCs out of 10,000 peripheral blood mononuclear cells, representing as low as approximately 0.1 % with a reasonable number of false positive events. Additionally, we present initial results on a theranostic approach using 5-ALA converted to protoporphyrin IX. The outcomes of this study might contribute significantly to the further development of CTC detection and the overall detection and treatment of cancer.

Molecular Determinants for Photodynamic Therapy Resistance and Improved Photosensitizer Delivery in Glioma

Gliomas account for 24% of all the primary brain and Central Nervous System (CNS) tumors. These tumors are diverse in cellular origin, genetic profile, and morphology but collectively have one of the most dismal prognoses of all cancers. Work is constantly underway to discover a new effective form of glioma therapy. Photodynamic therapy (PDT) may be one of them. It involves the local or systemic application of a photosensitive compound-a photosensitizer (PS)-which accumulates in the affected tissues. Photosensitizer molecules absorb light of the appropriate wavelength, initiating the activation processes leading to the formation of reactive oxygen species and the selective destruction of inappropriate cells. Research focusing on the effective use of PDT in glioma therapy is already underway with promising results. In our work, we provide detailed insights into the molecular changes in glioma after photodynamic therapy. We describe a number of molecules that may contribute to the resistance of glioma cells to PDT, such as the adenosine triphosphate (ATP)-binding cassette efflux transporter G2, glutathione, ferrochelatase, heme oxygenase, and hypoxia-inducible factor 1. We identify molecular targets that can be used to improve the photosensitizer delivery to glioma cells, such as the epithelial growth factor receptor, neuropilin-1, low-density lipoprotein receptor, and neuropeptide Y receptors. We note that PDT can increase the expression of some molecules that reduce the effectiveness of therapy, such as Vascular endothelial growth factor (VEGF), glutamate, and nitric oxide. However, the scientific literature lacks clear data on the effects of PDT on many of the molecules described, and the available reports are often contradictory. In our work, we highlight the gaps in this knowledge and point to directions for further research that may enhance the efficacy of PDT in the treatment of glioma.

Increasing the Dye Payload of Cetuximab-IRDye800CW Enables Photodynamic Therapy

Cetuximab (Cet)-IRDye800CW, among other antibody-IRDye800CW conjugates, is a potentially effective tool for delineating tumor margins during fluorescence image-guided surgery (IGS). However, residual disease often leads to recurrence. Photodynamic therapy (PDT) following IGS is proposed as an approach to eliminate residual disease but suffers from a lack of molecular specificity for cancer cells. Antibody-targeted PDT offers a potential solution for this specificity problem. In this study, we show, for the first time, that Cet-IRDye800CW is capable of antibody-targeted PDT in vitro when the payload of dye molecules is increased from 2 (clinical version) to 11 per antibody. Cet-IRDye800CW (1:11) produces singlet oxygen, hydroxyl radicals, and peroxynitrite upon activation with 810 nm light. In vitro assays on FaDu head and neck cancer cells confirm that Cet-IRDye800CW (1:11) maintains cancer cell binding specificity and is capable of inducing up to ∼90% phototoxicity in FaDu cancer cells. The phototoxicity of Cet-IRDye800CW conjugates using 810 nm light follows a dye payload-dependent trend. Cet-IRDye800CW (1:11) is also found to be more phototoxic to FaDu cancer cells and less toxic in the dark than the approved chromophore indocyanine green, which can also act as a PDT agent. We propose that antibody-targeted PDT using high-payload Cet-IRDye800CW (1:11) could hold potential for eliminating residual disease postoperatively when using sustained illumination devices, such as fiber optic patches and implantable surgical bed balloon applicators. This approach could also potentially be applicable to a wide variety of resectable cancers that are amenable to IGS-PDT, using their respective approved full-length antibodies as a template for high-payload IRDye800CW conjugation.

Pharmaceutical equivalent 5-aminolevulinic acid fluorescence guided resection of central nervous system tumors: feasibility, safeness and cost-benefit considerations

PURPOSE

5-aminolevulinic acid (5-ALA) fluorescence-guided resection (FGR) has been an essential tool in the 'standard of care' of malignant gliomas. Over the last two decades, its indications have been extended to other neoplasms, such as metastases and meningiomas. However, its availability and cost-benefit still pose a challenge for widespread use. The present article reports a retrospective series of 707 cases of central nervous system (CNS) tumors submitted to FGR with pharmacological equivalent 5-ALA and discusses financial implications, feasibility and safeness.

METHODS

From December 2015 to February 2024, a retrospective single institution series of 707 cases of 5-ALA FGR were analyzed. Age, gender, 5-ALA dosage, intraoperative fluorescence finding, diagnosis and adverse effects were recorded. Financial impact in the surgical treatment cost were also reported.

RESULTS

there was an additional cost estimated in $300 dollars for each case, increasing from 2,37 to 3,28% of the total hospitalization cost. There were 19 (2,69%) cases of asymptomatic photosensitive reaction and 2 (0,28%) cases of photosensitive reaction requiring symptomatic treatment. 1 (0,14%) patient had a cutaneous rash sustained for up to 10 days. No other complications related to the method were evident. In 3 (0,42%) cases of patients with intracranial hypertension, there was vomiting after administration.

CONCLUSION

FGR with pharmacological equivalent 5-ALA can be considered safe and efficient and incorporates a small increase in hospital expenses. It constitutes a reliable solution in avoiding prohibitive costs worldwide, especially in countries where commercial 5-ALA is unavailable.

Long term follow-up of patients with newly diagnosed glioblastoma treated by intraoperative photodynamic therapy: an update from the INDYGO trial (NCT03048240)

PURPOSE

Glioblastoma remains incurable despite optimal multimodal management. The interim analysis of open label, single arm INDYGO pilot trial showed actuarial 12-months progression-free survival (PFS) of 60% (median 17.1 months), actuarial 12-months overall survival (OS) of 80% (median 23.1 months). We report updated, exploratory analyses of OS, PFS, and health-related quality of life (HRQOL) for patients receiving intraoperative photodynamic therapy (PDT) with 5-aminolevulinic acid hydrochloride (5-ALA HCl).

METHODS

Ten patients were included (May 2017 - April 2021) for standardized therapeutic approach including 5-ALA HCl fluorescence-guided surgery (FGS), followed by intraoperative PDT with a single 200 J/cm2 dose of light. Postoperatively, patients received adjuvant therapy (Stupp protocol) then followed every 3 months (clinical and cerebral MRI) and until disease progression and/or death. Procedure safety and toxicity occurring during the first four weeks after PDT were assessed. Data concerning relapse, HRQOL and survival were prospectively collected and analyzed.

RESULTS

At the cut-off date (i.e., November 1st 2023), median follow-up was 23 months (9,7-71,4). No unacceptable or unexpected toxicities and no treatment-related deaths occurred during the study. Kaplan-Meier estimated 23.4 months median OS, actuarial 12-month PFS rate 60%, actuarial 12-month, 24-month, and 5-year OS rates 80%, 50% and 40%, respectively. Four patients were still alive (1 patient free of recurrence).

CONCLUSION

At 5 years-follow-up, intraoperative PDT with surgical maximal excision as initial therapy and standard adjuvant treatment suggests an increase of time to recurrence and overall survival in a high proportion of patients. Quality of life was maintained without any severe side effects.

TRIAL REGISTRATION NCT NUMBER

NCT03048240. EudraCT number: 2016-002706-39.

Recurrent Glioblastoma-Molecular Underpinnings and Evolving Treatment Paradigms

Glioblastoma is the most common and lethal central nervous system malignancy with a median survival after progression of only 6-9 months. Major biochemical mechanisms implicated in glioblastoma recurrence include aberrant molecular pathways, a recurrence-inducing tumor microenvironment, and epigenetic modifications. Contemporary standard-of-care (surgery, radiation, chemotherapy, and tumor treating fields) helps to control the primary tumor but rarely prevents relapse. Cytoreductive treatment such as surgery has shown benefits in recurrent glioblastoma; however, its use remains controversial. Several innovative treatments are emerging for recurrent glioblastoma, including checkpoint inhibitors, chimeric antigen receptor T cell therapy, oncolytic virotherapy, nanoparticle delivery, laser interstitial thermal therapy, and photodynamic therapy. This review seeks to provide readers with an overview of (1) recent discoveries in the molecular basis of recurrence; (2) the role of surgery in treating recurrence; and (3) novel treatment paradigms emerging for recurrent glioblastoma.

Association of 5-aminolevulinic acid fluorescence guided resection with photodynamic therapy in recurrent glioblastoma: a matched cohort study

PURPOSE

Glioblastoma is a malignant and aggressive brain tumour that, although there have been improvements in the first line treatment, there is still no consensus regarding the best standard of care (SOC) upon its inevitable recurrence. There are novel adjuvant therapies that aim to improve local disease control. Nowadays, the association of intraoperative photodynamic therapy (PDT) immediately after a 5-aminolevulinic acid (5-ALA) fluorescence-guided resection (FGR) in malignant gliomas surgery has emerged as a potential and feasible strategy to increase the extent of safe resection and destroy residual tumour in the surgical cavity borders, respectively.

OBJECTIVES

To assess the survival rates and safety of the association of intraoperative PDT with 5-ALA FGR, in comparison with a 5-ALA FGR alone, in patients with recurrent glioblastoma.

METHODS

This article describes a matched-pair cohort study with two groups of patients submitted to 5-ALA FGR for recurrent glioblastoma. Group 1 was a prospective series of 11 consecutive cases submitted to 5-ALA FGR plus intraoperative PDT; group 2 was a historical series of 11 consecutive cases submitted to 5-ALA FGR alone. Age, sex, Karnofsky performance scale (KPS), 5-ALA post-resection status, T1-contrast-enhanced extent of resection (EOR), previous and post pathology, IDH (Isocitrate dehydrogenase), Ki67, previous and post treatment, brain magnetic resonance imaging (MRI) controls and surgical complications were documented.

RESULTS

The Mantel-Cox test showed a significant difference between the survival rates (p = 0.008) of both groups. 4 postoperative complications occurred (36.6%) in each group. As of the last follow-up (January 2024), 7/11 patients in group 1, and 0/11 patients in group 2 were still alive. 6- and 12-months post-treatment, a survival proportion of 71,59% and 57,27% is expected in group 1, versus 45,45% and 9,09% in group 2, respectively. 6 months post-treatment, a progression free survival (PFS) of 61,36% and 18,18% is expected in group 1 and group 2, respectively.

CONCLUSION

The association of PDT immediately after 5-ALA FGR for recurrent malignant glioma seems to be associated with better survival without additional or severe morbidity. Despite the need for larger, randomized series, the proposed treatment is a feasible and safe addition to the reoperation.

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

Carrier-Free, Amorphous Verteporfin Nanodrug for Enhanced Photodynamic Cancer Therapy and Brain Drug Delivery

Glioblastoma (GBM) is hard to treat due to cellular invasion into functioning brain tissues, limited drug delivery, and evolved treatment resistance. Recurrence is nearly universal even after surgery, chemotherapy, and radiation. Photodynamic therapy (PDT) involves photosensitizer administration followed by light activation to generate reactive oxygen species at tumor sites, thereby killing cells or inducing biological changes. PDT can ablate unresectable GBM and sensitize tumors to chemotherapy. Verteporfin (VP) is a promising photosensitizer that relies on liposomal carriers for clinical use. While lipids increase VP's solubility, they also reduce intracellular photosensitizer accumulation. Here, a pure-drug nanoformulation of VP, termed "NanoVP", eliminating the need for lipids, excipients, or stabilizers is reported. NanoVP has a tunable size (65-150 nm) and 1500-fold higher photosensitizer loading capacity than liposomal VP. NanoVP shows a 2-fold increase in photosensitizer uptake and superior PDT efficacy in GBM cells compared to liposomal VP. In mouse models, NanoVP-PDT improved tumor control and extended animal survival, outperforming liposomal VP and 5-aminolevulinic acid (5-ALA). Moreover, low-dose NanoVP-PDT can safely open the blood-brain barrier, increasing drug accumulation in rat brains by 5.5-fold compared to 5-ALA. NanoVP is a new photosensitizer formulation that has the potential to facilitate PDT for the treatment of GBM.

Beyond fluorescence-guided resection: 5-ALA-based glioblastoma therapies

Glioblastoma is the most common primary malignant brain tumor. Despite advances in multimodal concepts over the last decades, prognosis remains poor. Treatment of patients with glioblastoma remains a considerable challenge due to the infiltrative nature of the tumor, rapid growth rates, and tumor heterogeneity. Standard therapy consists of maximally safe microsurgical resection followed by adjuvant radio- and chemotherapy with temozolomide. In recent years, local therapies have been extensively investigated in experimental as well as translational levels. External stimuli-responsive therapies such as Photodynamic Therapy (PDT), Sonodynamic Therapy (SDT) and Radiodynamic Therapy (RDT) can induce cell death mechanisms via generation of reactive oxygen species (ROS) after administration of five-aminolevulinic acid (5-ALA), which induces the formation of sensitizing porphyrins within tumor tissue. Preliminary data from clinical trials are available. The aim of this review is to summarize the status of such therapeutic approaches as an adjunct to current standard therapy in glioblastoma.

Current Photodynamic Therapy for Glioma Treatment: An Update

Research on the development of photodynamic therapy for the treatment of brain tumors has shown promise in the treatment of this highly aggressive form of brain cancer. Analysis of both in vivo studies and clinical studies shows that photodynamic therapy can provide significant benefits, such as an improved median rate of survival. The use of photodynamic therapy is characterized by relatively few side effects, which is a significant advantage compared to conventional treatment methods such as often-used brain tumor surgery, advanced radiotherapy, and classic chemotherapy. Continued research in this area could bring significant advances, influencing future standards of treatment for this difficult and deadly disease.

Versatile Peptide-Based Nanosystems for Photodynamic Therapy

Photodynamic therapy (PDT) has become an important therapeutic strategy because it is highly controllable, effective, and does not cause drug resistance. Moreover, precise delivery of photosensitizers to tumor lesions can greatly reduce the amount of drug administered and optimize therapeutic outcomes. As alternatives to protein antibodies, peptides have been applied as useful targeting ligands for targeted biomedical imaging, drug delivery and PDT. In addition, other functionalities of peptides such as stimuli responsiveness, self-assembly, and therapeutic activity can be integrated with photosensitizers to yield versatile peptide-based nanosystems for PDT. In this article, we start with a brief introduction to PDT and peptide-based nanosystems, followed by more detailed descriptions about the structure, property, and architecture of peptides as background information. Finally, the most recent advances in peptide-based nanosystems for PDT are emphasized and summarized according to the functionalities of peptide in the system to reveal the design and development principle in different therapeutic circumstances. We hope this review could provide useful insights and valuable reference for the development of peptide-based nanosystems for PDT.

Simulating photodynamic therapy for the treatment of glioblastoma using Monte Carlo radiative transport

Significance

Glioblastoma (GBM) is a rare but deadly form of brain tumor with a low median survival rate of 14.6 months, due to its resistance to treatment. An independent simulation of the INtraoperative photoDYnamic therapy for GliOblastoma (INDYGO) trial, a clinical trial aiming to treat the GBM resection cavity with photodynamic therapy (PDT) via a laser coupled balloon device, is demonstrated.

Aim

To develop a framework providing increased understanding for the PDT treatment, its parameters, and their impact on the clinical outcome.

Approach

We use Monte Carlo radiative transport techniques within a computational brain model containing a GBM to simulate light path and PDT effects. Treatment parameters (laser power, photosensitizer concentration, and irradiation time) are considered, as well as PDT's impact on brain tissue temperature.

Results

The simulation suggests that 39% of post-resection GBM cells are killed at the end of treatment when using the standard INDYGO trial protocol (light fluence = 200    J / cm 2 at balloon wall) and assuming an initial photosensitizer concentration of 5    μ M . Increases in treatment time and light power (light fluence = 400    J / cm 2 at balloon wall) result in further cell kill but increase brain cell temperature, which potentially affects treatment safety. Increasing the p hotosensitizer concentration produces the most significant increase in cell kill, with 61% of GBM cells killed when doubling concentration to 10    μ M and keeping the treatment time and power the same. According to these simulations, the standard trial protocol is reasonably well optimized with improvements in cell kill difficult to achieve without potentially dangerous increases in temperature. To improve treatment outcome, focus should be placed on improving the photosensitizer.

Conclusions

With further development and optimization, the simulation could have potential clinical benefit and be used to help plan and optimize intraoperative PDT treatment for GBM.

ROS regulation in gliomas: implications for treatment strategies

Gliomas are one of the most common primary malignant tumours of the central nervous system (CNS), of which glioblastomas (GBMs) are the most common and destructive type. The glioma tumour microenvironment (TME) has unique characteristics, such as hypoxia, the blood-brain barrier (BBB), reactive oxygen species (ROS) and tumour neovascularization. Therefore, the traditional treatment effect is limited. As cellular oxidative metabolites, ROS not only promote the occurrence and development of gliomas but also affect immune cells in the immune microenvironment. In contrast, either too high or too low ROS levels are detrimental to the survival of glioma cells, which indicates the threshold of ROS. Therefore, an in-depth understanding of the mechanisms of ROS production and scavenging, the threshold of ROS, and the role of ROS in the glioma TME can provide new methods and strategies for glioma treatment. Current methods to increase ROS include photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT), etc., and methods to eliminate ROS include the ingestion of antioxidants. Increasing/scavenging ROS is potentially applicable treatment, and further studies will help to provide more effective strategies for glioma treatment.

Novel Iron-Chelating Prodrug Significantly Enhanced Fluorescence-Mediated Detection of Glioma Cells Experimentally In Vitro

(1) Background: The protoporphyrin IX (PpIX)-mediated fluorescence-guided resection and interoperative photodynamic therapy (PDT) of remaining cells may be effective adjuvants to the resection of glioma. Both processes may be enhanced by increasing intracellular PpIX concentrations, which can be achieved through iron chelation. AP2-18 is a novel combinational drug, which ester-links a PpIX precursor (aminolaevulinic acid; ALA) to an iron-chelating agent (CP94). (2) Methods: Human glioma U-87 MG cells were cultured in 96-well plates for 24 h and incubated for 3 or 6 h with various test compound combinations: ALA (±) CP94, methyl aminolevulinate (MAL) (±) CP94 and AP2-18. PpIX fluorescence was measured at 0, 3 or 6 h with a Bio-tek Synergy HT plate reader, as well as immediately after irradiation with a 635 nm red light (Aktilite CL16 LED array), representing the PDT procedure. Cell viability post-irradiation was assessed using the neutral red assay. (3) Results: AP2-18 significantly increased PpIX fluorescence compared to all other test compounds. All treatment protocols effectively achieved PDT-induced cytotoxicity, with no significant difference between test compound combinations. (4) Conclusions: AP2-18 has potential to improve the efficacy of fluorescence-guided resection either with or without the subsequent intraoperative PDT of glioma. Future work should feature a more complex in vitro model of the glioma microenvironment.

Ruthenium-Based Photoactivated Chemotherapy

Ruthenium(II) polypyridyl complexes form a vast family of molecules characterized by their finely tuned photochemical and photophysical properties. Their ability to undergo excited-state deactivation via photosubstitution reactions makes them quite unique in inorganic photochemistry. As a consequence, they have been used, in general, for building dynamic molecular systems responsive to light but, more particularly, in the field of oncology, as prodrugs for a new cancer treatment modality called photoactivated chemotherapy (PACT). Indeed, the ability of a coordination bond to be selectively broken under visible light irradiation offers fascinating perspectives in oncology: it is possible to make poorly toxic agents in the dark that become activated toward cancer cell killing by simple visible light irradiation of the compound inside a tumor. In this Perspective, we review the most important concepts behind the PACT idea, the relationship between ruthenium compounds used for PACT and those used for a related phototherapeutic approach called photodynamic therapy (PDT), and we discuss important questions about real-life applications of PACT in the clinic. We conclude this Perspective with important challenges in the field and an outlook.

Photodynamic augmentation of oncolytic virus therapy for central nervous system malignancies

Oncolytic viruses (OVs) have emerged as a clinical therapeutic modality potentially effective for cancers that evade conventional therapies, including central nervous system malignancies. Rationally designed combinatorial strategies can augment the efficacy of OVs by boosting tumor-selective cytotoxicity and modulating the tumor microenvironment (TME). Photodynamic therapy (PDT) of cancer not only mediates direct neoplastic cell death but also primes the TME to sensitize the tumor to secondary therapies, allowing for the combination of two potentially synergistic therapies with broader targets. Here, we created G47Δ-KR, clinical oncolytic herpes simplex virus G47Δ that expresses photosensitizer protein KillerRed (KR). Optical properties and cytotoxic effects of G47Δ-KR infection followed by amber LED illumination (peak wavelength: 585-595 nm) were examined in human glioblastoma (GBM) and malignant meningioma (MM) models in vitro. G47Δ-KR infection of tumor cells mediated KR expression that was activated by LED and produced reactive oxygen species, leading to cell death that was more robust than G47Δ-KR without light. In vivo, we tested photodynamic-oncolytic virus (PD-OV) therapy employing intratumoral injection of G47Δ-KR followed by laser light tumor irradiation (wavelength: 585 nm) in GBM and MM xenografts. PD-OV therapy was feasible in these models and resulted in potent anti-tumor effects that were superior to G47Δ-KR alone (without laser light) or laser light alone. RNA sequencing analysis of post-treatment tumor samples revealed PD-OV therapy-induced increases in TME infiltration of variable immune cell types. This study thus demonstrated the proof-of-concept that G47Δ-KR enables PD-OV therapy for neuro-oncological malignancies and warrants further research to advance potential clinical translation.

Photodynamic therapy and associated targeting methods for treatment of brain cancer

Brain tumors, including glioblastoma multiforme, are currently a cause of suffering and death of tens of thousands of people worldwide. Despite advances in clinical treatment, the average patient survival time from the moment of diagnosis of glioblastoma multiforme and application of standard treatment methods such as surgical resection, radio- and chemotherapy, is less than 4 years. The continuing development of new therapeutic methods for targeting and treating brain tumors may extend life and provide greater comfort to patients. One such developing therapeutic method is photodynamic therapy. Photodynamic therapy is a progressive method of therapy used in dermatology, dentistry, ophthalmology, and has found use as an antimicrobial agent. It has also found wide application in photodiagnosis. Photodynamic therapy requires the presence of three necessary components: a clinically approved photosensitizer, oxygen and light. This paper is a review of selected literature from Pubmed and Scopus scientific databases in the field of photodynamic therapy in brain tumors with an emphasis on glioblastoma treatment.

Photosensitizers for Photodynamic Therapy of Brain Cancers-A Review

On average, there are about 300,000 new cases of brain cancer each year. Studies have shown that brain and central nervous system tumors are among the top ten causes of death. Due to the extent of this problem and the percentage of patients suffering from brain tumors, innovative therapeutic treatment methods are constantly being sought. One such innovative therapeutic method is photodynamic therapy (PDT). Photodynamic therapy is an alternative and unique technique widely used in dermatology and other fields of medicine for the treatment of oncological and nononcological lesions. Photodynamic therapy consists of the destruction of cancer cells and inducing inflammatory changes by using laser light of a specific wavelength in combination with the application of a photosensitizer. The most commonly used photosensitizers include 5-aminolevulinic acid for the enzymatic generation of protoporphyrin IX, Temoporfin-THPC, Photofrin, Hypericin and Talaporfin. This paper reviews the photosensitizers commonly used in photodynamic therapy for brain tumors. An overview of all three generations of photosensitizers is presented. Along with an indication of the limitations of the treatment of brain tumors, intraoperative photodynamic therapy and its possibilities are described as an alternative therapeutic method.

The Effect of Photosensitizer Metalation Incorporated into Arene-Ruthenium Assemblies on Prostate Cancer

Prostate cancer is the second most common cancer for men and a major health issue. Despite treatments, a lot of side effects are observed. Photodynamic therapy is a non-invasive method that uses photosensitizers and light to induce cell death through the intramolecular generation of reactive oxygen species, having almost no side effects. However, some of the PSs used in PDT show inherent low solubility in biological media, and accordingly, functionalization or vectorization is needed to ensure internalization. To this end, we have used arene-ruthenium cages in order to deliver PSs to cancer cells. These metalla-assemblies can host PSs inside their cavity or be constructed with PS building blocks. In this study, we wanted to determine if the addition of metals (Mg, Co, Zn) in the center of these PSs plays a role. Our results show that most of the compounds induce cytotoxic effects on DU 145 and PC-3 human prostate cancer cells. Localization by fluorescence confirms the internalization of the assemblies in the cytoplasm. An analysis of apoptotic processes shows a cleavage of pro-caspase-3 and poly-ADP-ribose polymerase, thus leading to a strong induction of DNA fragmentation. Finally, the presence of metals in the PS decreases PDT's effect and can even annihilate it.

Systematic Review of Photodynamic Therapy in Gliomas

Over the last 20 years, gliomas have made up over 89% of malignant CNS tumor cases in the American population (NIH SEER). Within this, glioblastoma is the most common subtype, comprising 57% of all glioma cases. Being highly aggressive, this deadly disease is known for its high genetic and phenotypic heterogeneity, rendering a complicated disease course. The current standard of care consists of maximally safe tumor resection concurrent with chemoradiotherapy. However, despite advances in technology and therapeutic modalities, rates of disease recurrence are still high and survivability remains low. Given the delicate nature of the tumor location, remaining margins following resection often initiate disease recurrence. Photodynamic therapy (PDT) is a therapeutic modality that, following the administration of a non-toxic photosensitizer, induces tumor-specific anti-cancer effects after localized, wavelength-specific illumination. Its effect against malignant glioma has been studied extensively over the last 30 years, in pre-clinical and clinical trials. Here, we provide a comprehensive review of the three generations of photosensitizers alongside their mechanisms of action, limitations, and future directions.

Photodynamic Therapy for Glioblastoma: Illuminating the Path toward Clinical Applicability

Glioblastoma (GBM) is the most common adult brain cancer. Despite extensive treatment protocols comprised of maximal surgical resection and adjuvant chemo-radiation, all glioblastomas recur and are eventually fatal. Emerging as a novel investigation for GBM treatment, photodynamic therapy (PDT) is a light-based modality that offers spatially and temporally specific delivery of anti-cancer therapy with limited systemic toxicity, making it an attractive option to target GBM cells remaining beyond the margins of surgical resection. Prior PDT approaches in GBM have been predominantly based on 5-aminolevulinic acid (5-ALA), a systemically administered drug that is metabolized only in cancer cells, prompting the release of reactive oxygen species (ROS), inducing tumor cell death via apoptosis. Hence, this review sets out to provide an overview of current PDT strategies, specifically addressing both the potential and shortcomings of 5-ALA as the most implemented photosensitizer. Subsequently, the challenges that impede the clinical translation of PDT are thoroughly analyzed, considering relevant gaps in the current PDT literature, such as variable uptake of 5-ALA by tumor cells, insufficient tissue penetrance of visible light, and poor oxygen recovery in 5-ALA-based PDT. Finally, novel investigations with the potential to improve the clinical applicability of PDT are highlighted, including longitudinal PDT delivery, photoimmunotherapy, nanoparticle-linked photosensitizers, and near-infrared radiation. The review concludes with commentary on clinical trials currently furthering the field of PDT for GBM. Ultimately, through addressing barriers to clinical translation of PDT and proposing solutions, this review provides a path for optimizing PDT as a paradigm-shifting treatment for GBM.

Preclinical Studies with Glioblastoma Brain Organoid Co-Cultures Show Efficient 5-ALA Photodynamic Therapy

BACKGROUND

The high recurrence of glioblastoma (GB) that occurs adjacent to the resection cavity within two years of diagnosis urges an improvement of therapies oriented to GB local control. Photodynamic therapy (PDT) has been proposed to cleanse infiltrating tumor cells from parenchyma to ameliorate short long-term progression-free survival. We examined 5-aminolevulinic acid (5-ALA)-mediated PDT effects as therapeutical treatment and determined optimal conditions for PDT efficacy without causing phototoxic injury to the normal brain tissue.

METHODS

We used a platform of Glioma Initiation Cells (GICs) infiltrating cerebral organoids with two different glioblastoma cells, GIC7 and PG88. We measured GICs-5-ALA uptake and PDT/5-ALA activity in dose-response curves and the efficacy of the treatment by measuring proliferative activity and apoptosis.

RESULTS

5-ALA (50 and 100 µg/mL) was applied, and the release of protoporphyrin IX (PpIX) fluorescence measures demonstrated that the emission of PpIX increases progressively until its stabilization at 24 h. Moreover, decreased proliferation and increased apoptosis corroborated the effect of 5-ALA/PDT on cancer cells without altering normal cells.

CONCLUSIONS

We provide evidence about the effectiveness of PDT to treat high proliferative GB cells in a complex in vitro system, which combines normal and cancer cells and is a useful tool to standardize new strategic therapies.

Low-Level Laser Treatment Induces the Blood-Brain Barrier Opening and the Brain Drainage System Activation: Delivery of Liposomes into Mouse Glioblastoma

The progress in brain diseases treatment is limited by the blood-brain barrier (BBB), which prevents delivery of the vast majority of drugs from the blood into the brain. In this study, we discover unknown phenomenon of opening of the BBBB (BBBO) by low-level laser treatment (LLLT, 1268 nm) in the mouse cortex. LLLT-BBBO is accompanied by activation of the brain drainage system contributing effective delivery of liposomes into glioblastoma (GBM). The LLLT induces the generation of singlet oxygen without photosensitizers (PSs) in the blood endothelial cells and astrocytes, which can be a trigger mechanism of BBBO. LLLT-BBBO causes activation of the ABC-transport system with a temporal decrease in the expression of tight junction proteins. The BBB recovery is accompanied by activation of neuronal metabolic activity and stabilization of the BBB permeability. LLLT-BBBO can be used as a new opportunity of interstitial PS-free photodynamic therapy (PDT) for modulation of brain tumor immunity and improvement of immuno-therapy for GBM in infants in whom PDT with PSs, radio- and chemotherapy are strongly limited, as well as in adults with a high allergic reaction to PSs.

Supraorbital transciliary approach as primary route to fronto-basal high grade glioma resection with 5-Aminolevulinic Acid use: Technical note

BACKGROUND

Gliomas are diffuse intra-axial lesions, which can be accessed by multiple surgical corridors for a same location depending on the surgeon's preference. 5-Aminolevulinic Acid use facilitates the extend of resection in case of high-grade gliomas, especially when differentiating normal brain from tumor periphery is challenging.

METHODS

Complete resection of glioblastoma via a supraorbital transciliary approach with 5-Aminolevulinic Acid use was performed without any complications, as demonstrated on postoperative MRI.

RESULTS

Patient was discharged on the third postoperative day. Wound follow-up shows good cosmetic result. Patient underwent concomitant chemo-radiation (Temozolomide- 60Gy) and adjuvant chemotherapy (Temozolomide). No tumor recurrence was noted at six months follow-up.

CONCLUSION

In selected cases, supraorbital transciliary approach could be proposed as primary approach as it provides the advantage of full control over all the vasculo-nervous structures at skull base without the necessity of protective brain retractor use while the 5-Aminolevulinic Acid use allows a gross total resection.

[Intraoperative photodynamic therapy in complex treatment of malignant gliomas]

Treatment of malignant gliomas is an extremely difficult objective associated with difficult choice of correct strategy. Photodynamic therapy is still not the treatment standard in these patients although this approach significantly improves treatment outcomes in surgery of gliomas.

OBJECTIVE

To demonstrate the possibilities of chlorin e6-mediated photodynamic therapy for malignant glial tumors.

MATERIAL AND METHODS

There were 161 patients with malignant supratentorial glial tumors who were treated at the Polenov Russian Neurosurgery Institute between 2009 and 2016. Eighty patients comprised the main group (photodynamic therapy), 81 ones - control group (without photodynamic therapy).

RESULTS

Photodynamic therapy in complex treatment of malignant brain gliomas significantly increases overall survival in patients with Grade III gliomas up to 39.1±5.5 months (control group - 22.8±3.3 months) and Grade IV gliomas up to 20.7±4.7 months (control group - 13.5±2.3 months) (p=0.0002). This method also increases relapse-free period in patients with Grade III gliomas up to 21.7±3.4 months (control group - 15.8±3.1 months) (p=0.0002) and Grade IV gliomas up to 11.1±2.1 months (control group - 8.0±2.3 months) (p=0.0001).

Photodynamic therapy in glioblastoma: Detection of intraoperative inadvertent 5-ALA mediated photodynamic therapeutical effect after gross total resection

Introduction

Glioblastoma (GBM) remains the most frequent and lethal primary brain tumor in adults, despite advancements in surgical resection techniques and adjuvant chemo- and radiotherapy. The most frequent recurrence pattern (75-90%) occurs in the form of continuous growth from the border of the surgical cavity, thus emphasizing the need for locoregional tumor control. Fluorescence-guided surgical resection using 5-ALA has been widely implemented in surgical protocols for such tumors. Recent literature also highlights the applicability of 5-ALA-mediated photodynamic therapy to obtain locoregional tumor control further. This study aims to identify if 5-ALA mediated photodynamic therapeutic effect after gross total glioblastoma resection has inadvertently occurred due to the exposition of protoporphyrin IX charged peripheral tumoral cells to operative room light sources.

Methods

Of 146 patients who were intervened from glioblastoma between 2015 and 2020, 33 were included in the present study. Strict gross total resection (without supralocal resection) had been accomplished, and adjuvant chemoradiotherapy protocol was administered. Two comparison groups were created regarding the location of the recurrence (group A: up to 1 centimeter from the surgical cavity, and group B: beyond 1 centimeter from the surgical cavity). The cutoff point was determined to be 1 centimeter because of the visible light penetrance to the normal brain tissue.

Results

In univariate analysis, both groups only differed regarding 5-ALA administration, which was significantly related to a minor relative risk of presenting the recurrence within the first centimeter from the surgical cavity (Relative Risk = 0,655 (95% CI 0,442-0,970), p-value=0,046). Results obtained in univariate analysis were corroborated posteriorly in multivariate analysis (RR=0,730 (95% CI 0,340-0,980), p=0,017).

Discussion

In the present study, a probable inadvertent 5-ALA photodynamic therapeutical effect has been detected in vivo. This finding widely opens the door for further research on this promising theragnostic tool.

Advanced techniques for performing photodynamic therapy in deep-seated tissues

Photodynamic therapy (PDT) is a promising localized cancer treatment modality. It has been used successfully to treat a range of dermatological conditions with comparable efficacy to conventional treatments. However, some drawbacks limit the clinical utility of PDT in treating deep-seated tumors. Notably, the penetration limitation of UV and visible light, commonly applied to activate photosensitizers, makes PDT incompetent in treating deep-seated tumors. Development in light delivery technologies, especially fiber optics, led to improved clinical strategies for accessing deep tissues for irradiation. However, PDT efficacy issues remained partly due to light penetration limitations. In this review, we first summarized the current PDT applications for deep-seated tumor treatment. Then, the most recent progress in advanced techniques to overcome the light penetration limitation in PDT, including using functional nanomaterials that can either self-illuminate or be activated by near-infrared (NIR) light and X-rays as transducers, and implantable light delivery devices were discussed. Finally, current challenges and future opportunities of these technologies were discussed, which we hope may inspire the development of more effective techniques to enhance PDT efficacy against deep-seated tumors.

Photodynamic Opening of the Blood-Brain Barrier and the Meningeal Lymphatic System: The New Niche in Immunotherapy for Brain Tumors

Photodynamic therapy (PDT) is a promising add-on therapy to the current standard of care for patients with glioblastoma (GBM). The traditional explanation of the anti-cancer PDT effects involves the PDT-induced generation of a singlet oxygen in the GBM cells, which causes tumor cell death and microvasculature collapse. Recently, new vascular mechanisms of PDT associated with opening of the blood-brain barrier (OBBB) and the activation of functions of the meningeal lymphatic vessels have been discovered. In this review, we highlight the emerging trends and future promises of immunotherapy for brain tumors and discuss PDT-OBBB as a new niche and an important informative platform for the development of innovative pharmacological strategies for the modulation of brain tumor immunity and the improvement of immunotherapy for GBM.

Effect of 5-Aminolevulinic Acid Photodynamic Therapy with Transfer Factor Capsules in the Treatment of Multiple Plantar Warts

BACKGROUND

Plantar warts are a common cutaneous disease of the sole of the foot caused by human papillomavirus. Photodynamic therapy has gained increasing attention in the treatment of plantar warts.

OBJECTIVE

To investigate the effect of photodynamic therapy combined with transfer factor capsules in the treatment of multiple plantar warts.

METHODS

Sixty-one patients with multiple plantar warts who visited our outpatient department from September 2017 to August 2019 were randomly divided into two groups. Twenty-three patients received photodynamic therapy (treatment group) and thirty-eight received cryotherapy (control group). Both groups also received immune modulator transfer factor capsules. Skin lesion score, numeric rating scale- (NRS-) 10 score, recurrence rate, adverse reactions, and Dermatology Life Quality Index (DLQI) were analyzed in both groups.

RESULTS

The mean skin lesion score improved from 13.39 ± 3.88 before treatment to 1.48 ± 2.50 after the last treatment in the treatment group and from 12.47 ± 2.99 before treatment to 4.47 ± 3.67 after the last treatment in the control group. The success rate after 3 months of treatment was 86.96% in the treatment group and 39.47% in the control group. After 3 months of follow-up, the recurrence rate was significantly lower in the treatment group (20%) than in the control group (53.33%). The mean DLQI score at three months after treatment was significantly lower in the treatment group (3.61 ± 1.16) than in the control group (6.31 ± 2.59).

CONCLUSION

Photodynamic therapy combined with immunomodulators significantly increased the cure rate and reduced the recurrence rate of multiple plantar warts compared with traditional cryotherapy combined with immunomodulators.

Updates in intraoperative strategies for enhancing intra-axial brain tumor control

To ensure excellent postoperative clinical outcomes while preserving critical neurologic function, neurosurgeons who manage patients with intra-axial brain tumors can use intraoperative technologies and tools to achieve maximal safe resection. Neurosurgical oncology revolves around safe and optimal extent of resection, which further dictates subsequent treatment regimens and patient outcomes. Various methods can be adapted for treating both primary and secondary intra-axial brain lesions. We present a review of recent advances and published research centered on different innovative tools and techniques, including fluorescence-guided surgery, new methods of drug delivery, and minimally invasive procedural options.

Medical Device Advances in the Treatment of Glioblastoma

Despite decades of research and the growing emergence of new treatment modalities, Glioblastoma (GBM) frustratingly remains an incurable brain cancer with largely stagnant 5-year survival outcomes of around 5%. Historically, a significant challenge has been the effective delivery of anti-cancer treatment. This review aims to summarize key innovations in the field of medical devices, developed either to improve the delivery of existing treatments, for example that of chemo-radiotherapy, or provide novel treatments using devices, such as sonodynamic therapy, thermotherapy and electric field therapy. It will highlight current as well as emerging device technologies, non-invasive versus invasive approaches, and by doing so provide a detailed summary of evidence from clinical studies and trials undertaken to date. Potential limitations and current challenges are discussed whilst also highlighting the exciting potential of this developing field. It is hoped that this review will serve as a useful primer for clinicians, scientists, and engineers in the field, united by a shared goal to translate medical device innovations to help improve treatment outcomes for patients with this devastating disease.

Which cell death modality wins the contest for photodynamic therapy of cancer?

Photodynamic therapy (PDT) was discovered more than 100 years ago. Since then, many protocols and agents for PDT have been proposed for the treatment of several types of cancer. Traditionally, cell death induced by PDT was categorized into three types: apoptosis, cell death associated with autophagy, and necrosis. However, with the discovery of several other regulated cell death modalities in recent years, it has become clear that this is a rather simple understanding of the mechanisms of action of PDT. New observations revealed that cancer cells exposed to PDT can pass through various non-conventional cell death pathways, such as paraptosis, parthanatos, mitotic catastrophe, pyroptosis, necroptosis, and ferroptosis. Nowadays, immunogenic cell death (ICD) has become one of the most promising ways to eradicate tumor cells by activation of the T-cell adaptive immune response and induction of long-term immunological memory. ICD can be triggered by many anti-cancer treatment methods, including PDT. In this review, we critically discuss recent findings on the non-conventional cell death mechanisms triggered by PDT. Next, we emphasize the role and contribution of ICD in these PDT-induced non-conventional cell death modalities. Finally, we discuss the obstacles and propose several areas of research that will help to overcome these challenges and lead to the development of highly effective anti-cancer therapy based on PDT.

Refining Glioblastoma Surgery through the Use of Intra-Operative Fluorescence Imaging Agents

Glioblastoma (GBM) is the most aggressive adult brain tumour with a dismal 2-year survival rate of 26-33%. Maximal safe resection plays a crucial role in improving patient progression-free survival (PFS). Neurosurgeons have the significant challenge of delineating normal tissue from brain tumour to achieve the optimal extent of resection (EOR), with 5-Aminolevulinic Acid (5-ALA) the only clinically approved intra-operative fluorophore for GBM. This review aims to highlight the requirement for improved intra-operative imaging techniques, focusing on fluorescence-guided imaging (FGS) and the use of novel dyes with the potential to overcome the limitations of current FGS. The review was performed based on articles found in PubMed an.d Google Scholar, as well as articles identified in searched bibliographies between 2001 and 2022. Key words for searches included 'Glioblastoma' + 'Fluorophore'+ 'Novel' + 'Fluorescence Guided Surgery'. Current literature has favoured the approach of using targeted fluorophores to achieve specific accumulation in the tumour microenvironment, with biological conjugates leading the way. These conjugates target specific parts overexpressed in the tumour. The positive results in breast, ovarian and colorectal tissue are promising and may, therefore, be applied to intracranial neoplasms. Therefore, this design has the potential to produce favourable results in GBM by reducing the residual tumour, which translates to decreased tumour recurrence, morbidity and ultimately, mortality in GBM patients. Several preclinical studies have shown positive results with targeted dyes in distinguishing GBM cells from normal brain parenchyma, and targeted dyes in the Near-Infrared (NIR) emission range offer promising results, which may be valuable future alternatives.

Recent advances in the therapeutic strategies of glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most common, most formidable, and deadliest malignant types of primary astrocytoma with a poor prognosis. At present, the standard of care includes surgical tumor resection, followed by radiation therapy concomitant with chemotherapy and temozolomide. New developments and significant advances in the treatment of GBM have been achieved in recent decades. However, despite the advances, recurrence is often inevitable, and the survival of patients remains low. Various factors contribute to the difficulty in identifying an effective therapeutic option, among which are tumor complexity, the presence of the blood-brain barrier (BBB), and the presence of GBM cancer stem cells, prompting the need for improving existing treatment approaches and investigating new treatment alternatives for ameliorating the treatment strategies of GBM. In this review, we outline some of the most recent literature on the various available treatment options such as surgery, radiotherapy, cytotoxic chemotherapy, gene therapy, immunotherapy, phototherapy, nanotherapy, and tumor treating fields in the treatment of GBM, and we list some of the potential future directions of GBM. The reviewed studies confirm that GBM is a sophisticated disease with several challenges for scientists to address. Hence, more studies and a multimodal therapeutic approach are crucial to yield an effective cure and prolong the survival of GBM patients.

Advances in local therapy for glioblastoma - taking the fight to the tumour

Despite advances in neurosurgery, chemotherapy and radiotherapy, glioblastoma remains one of the most treatment-resistant CNS malignancies, and the tumour inevitably recurs. The majority of recurrences appear in or near the resection cavity, usually within the area that received the highest dose of radiation. Many new therapies focus on combatting these local recurrences by implementing treatments directly in or near the tumour bed. In this Review, we discuss the latest developments in local therapy for glioblastoma, focusing on recent preclinical and clinical trials. The approaches that we discuss include novel intraoperative techniques, various treatments of the surgical cavity, stereotactic injections directly into the tumour, and new developments in convection-enhanced delivery and intra-arterial treatments.