A randomised controlled trial of ALA vs. Photofrin photodynamic therapy for high-grade dysplasia arising in Barrett's oesophagus

NIR-activated multifunctional agents for the combined application in cancer imaging and therapy

Anticancer therapies that combine both diagnostic and therapeutic capabilities hold significant promise for enhancing treatment efficacy and patient outcomes. Among these, agents responsive to near-infrared (NIR) photons are of particular interest due to their negligible toxicity and multifunctionality. These compounds are not only effective in photodynamic therapy (PDT), but also serve as contrast agents in various imaging modalities, including fluorescence and photoacoustic imaging. In this review, we explore the photophysical and photochemical properties of NIR-activated porphyrin, cyanine, and phthalocyanines derivatives as well as aggregation-induced emission compounds, highlighting their application in synergistic detection, diagnosis, and therapy. Special attention is given to the design and optimization of these agents to achieve high photostability, efficient NIR absorption, and significant yields of fluorescence, heat, or reactive oxygen species (ROS) generation depending on the application. Additionally, we discuss the incorporation of these compounds into nanocarriers to enhance their solubility, stability, and target specificity. Such nanoparticle-based systems exhibit improved pharmacokinetics and pharmacodynamics, facilitating more effective tumor targeting and broadening the application range to photoacoustic imaging and photothermal therapy. Furthermore, we summarize the application of these NIR-responsive agents in multimodal imaging techniques, which combine the advantages of fluorescence and photoacoustic imaging to provide comprehensive diagnostic information. Finally, we address the current challenges and limitations of photodiagnosis and phototherapy and highlight some critical barriers to their clinical implementation. These include issues related to their phototoxicity, limited tissue penetration, and potential off-target effects. The review concludes by highlighting future research directions aimed at overcoming these obstacles, with a focus on the development of next-generation agents and platforms that offer enhanced therapeutic efficacy and imaging capabilities in the field of cancer treatment.

Highly functional duodenal stent with photosensitizers enables photodynamic therapy for metabolic syndrome treatment: Feasibility and safety study in a porcine model

Duodenal mucosal resurfacing (DMR) by thermal ablation of the duodenal mucosa is a minimally invasive endoscopic procedure for controlling metabolic syndrome (MS). However, thermal energy can cause adverse effects due to deep mucosal injury, necessitating an additional mucosal lifting process, which complicate the procedures. Therefore, we aimed to develop a similar procedure using non-thermal photodynamic therapy (PDT) for DMR using a highly functional metal stent covered with photosensitizers (PSs) to minimize the potential risks of thermal ablation injury. We developed a novel PS stent enabling the controlled release of radical oxygen species with specific structures to prevent stent migration and duodenal stricture after ablation and performed an animal study (n = 8) to demonstrate the feasibility and safety of PDT for DMR. The stents were placed for 7 days to prevent duodenal strictures after PDT. To confirm PDT efficacy, we stained for gastric inhibitory polypeptide (GIP) and glucose transporter isoform 1. The PS stents were deployed, and PDT was applied without evidence of duodenal stricture, pancreatitis, or hemorrhage in any of the pigs. Microscopic evaluation indicated apoptosis of the mucosal cells in the irradiated duodenum on days 7 and 14, which recovered after day 28. Immunohistochemistry revealed suppressed GIP expression in the mucosal wall of the irradiated duodenum. Endoscopic PDT for DMR using PS stents could be applied safely in a porcine model and may result in decreased GIP secretion, which is a crucial mechanism in MS treatment. Further clinical studies are required to explore its safety and efficacy in patients with MS.

Localized Photodynamic Therapy Using a Chlorin e6-Embedded Silicone-Covered Self-Expandable Metallic Stent as a Palliative Treatment for Malignant Esophageal Strictures

Localized photodynamic therapy (PDT) uses a polymeric-photosensitizer (PS)-embedded, covered self-expandable metallic stent (SEMS). PDT is minimally invasive and a noteworthy potential alternative for treating esophageal strictures, where surgery is not a viable option. However, preclinical evidence is insufficient, and optimized irradiation energy dose ranges for localized PDT are unclear. Herein, we validated the irradiation energy doses of the SEMS (embedded in a PS using chlorin e6 [Ce6] and covered in silicone) and PDT-induced tissue changes in a rat esophagus. Cytotoxicity and phototoxicity in the Ce6-embedded SEMS piece with laser irradiation were significantly higher than that of the silicone-covered SEMS with or without laser and the Ce6-embedded silicone-covered SEMS without laser groups (all p < 0.001). Moreover, surface morphology, atomic changes, and homogeneous coverage of the Ce6-embedded silicone-covered membrane were confirmed. The ablation range of the porcine liver was proportionally increased with the irradiation dose (all p < 0.001). The ablation region was identified at different irradiation energy doses of 50, 100, 200, and 400 J/cm2. The in vivo study in the rat esophagus comprised a control group and 100, 200, and 400 J/cm2 energy-dose groups. Finally, histology and immunohistochemistry (TUNEL and Ki67) confirmed that the optimized Ce6-embedded silicone-covered SEMS with selected irradiation energy doses (200 and 400 J/cm2) effectively damaged the esophageal tissue without ductal perforation. The polymeric PS-embedded silicone-covered SEMS can be easily placed via a minimally invasive approach and represents a promising new approach for the palliative treatment of malignant esophageal strictures.

Study on the effect of 5-aminolevulinic acid-mediated photodynamic therapy combined with cisplatin on human ovarian cancer OVCAR-3 ​cells

PURPOSE

This article explores the effect of 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT) combined with cisplatin (CDDP) on the apoptosis of human ovarian cancer cells and the mechanism of action of the combination therapy.

MATERIALS AND METHODS

Human ovarian cancer OVCAR-3 ​cells were cultured in vitro and divided into 5-ALA/PDT group, CDDP group and combined treatment group (5-ALA/PDT combined with different concentrations of CDDP). After administration of the corresponding drugs, a CCK-8 assay was used to detect the inhibition rate of cell proliferation. After Rhodamine 123 staining, mitochondrial membrane potential changes were observed under fluorescence microscopy. The apoptosis rate and reactive oxygen species (ROS) content were detected by flow cytometry. Western blotting was used to detect protein expression.

RESULTS

The CCK-8 assay showed that CDDP in combination with 5-ALA/PDT significantly enhanced cytotoxicity compared to treatment with CDDP alone and that low doses of CDDP were sufficient to induce these combination effects. The mitochondrial membrane potential in each combination treatment group gradually decreased with increasing CDDP concentration, while the apoptosis rate and reactive oxygen species (ROS) content detected by flow cytometry gradually increased. Western blotting assay showed that the expression of bax, cleaved caspase-9, cleaved caspase-3, and cleaved PARP was increased, while the expression of bcl-2, caspase-9, caspase-3, and PARP was decreased, and the differences were statistically significant (P ​< ​0.05).

CONCLUSIONS

In summary, 5-ALA/PDT combined with CDDP can effectively inhibit cell proliferation and promote apoptosis, and this combination may induce apoptosis by activating the mitochondrial pathway.

Advancements in photodynamic therapy of esophageal cancer

The poor prognosis of patients with esophageal cancer leads to the constant search for new ways of treatment of this disease. One of the methods used in high-grade dysplasia, superficial invasive carcinoma, and sometimes palliative care is photodynamic therapy (PDT). This method has come a long way from the first experimental studies to registration in the treatment of esophageal cancer and is constantly being improved and refined. This review describes esophageal cancer, current treatment methods, the introduction to PDT, the photosensitizers (PSs) used in esophageal carcinoma PDT, PDT in squamous cell carcinoma (SCC) of the esophagus, and PDT in invasive adenocarcinoma of the esophagus. For this review, research and review articles from PubMed and Web of Science databases were used. The keywords used were "photodynamic therapy in esophageal cancer" in the years 2000-2020. The total number of papers returned was 1,000. After the review was divided into topic blocks and the searched publications were analyzed, 117 articles were selected.

Comparison Between Two Antimicrobial Photodynamic Therapy Protocols for Oral Candidiasis in Patients Undergoing Treatment for Head and Neck Cancer: A two-arm, single-blind clinical trial

PURPOSE

This study aimed to compare the efficacy of Antimicrobial Photodynamic Therapy (aPDT) with 300 µmol/L of methylene blue and 8 µmol/L of curcumin on oral candidiasis patients with HNSCC undergoing treatment.

METHODS

A two-arm, single-blind clinical trial was performed. Following verification for eligibility (n = 447), 108 patients were included in the study. The study consisted of a group that received aPDT with methylene blue (n = 57) and another that received aPDT with curcumin (n = 51). The patients rinsed their mouths with an aqueous solution of 300 µmol/L of methylene blue and 8 µmol/L of curcumin in four sessions, and then the lesion was scraped for the subsequent RT-qPCR. The primary outcome was that no cure was presented for oral candidiasis after treatment. The secondary result was reducing the number of sites affected by oral candidiasis.

RESULTS

There was no difference in treatment failure evaluated by the necessity of drug prescription or Candida sp DNA quantification. However, clinically the methylene blue protocol reduced the number of infected anatomical sites compared to the curcumin protocol.

CONCLUSION

Methylene Blue aPDT reduced the number of infected anatomical sites compared to curcumin.

Endoscopic therapies for Barrett's esophagus

The management of Barrett's esophagus (BE) has evolved as newer technologies and novel methods are developed. Endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) are the initial interventions of choice for nodular BE, with ESD reserved for endoscopists highly trained in the technique and for larger lesions that would warrant en bloc resection. Resection should then be followed by ablative therapy, which remains first line in the treatment of BE with dysplasia. Although there is a myriad of ablation techniques available to the endoscopist, this review has found that radiofrequency ablation (RFA) continues to have the most robust safety and efficacy data to support its use despite a relatively high rate of recurrence. Cryotherapy and Hybrid-APC appear to be safe and effective as RFA alternatives, but further trials are still needed to directly compare their outcomes to RFA and ultimately guide changes in treatment decisions.

Pheophorbide co-encapsulated with Cisplatin in folate-decorated PLGA nanoparticles to treat nasopharyngeal carcinoma: Combination of chemotherapy and photodynamic therapy

The adverse effect and drug resistance of Cisplatin (CDDP) could be potential reduced by delivering in targeted nanoparticles and by combining with adjuvant therapy such as photodynamic therapy. In this study, F/CDPR-NP was formulated and characterized for all the physicochemical, biological and in vivo analysis. The results obtained from various in vitro and biological studies showed that encapsulation of CDDP and PBR in PLGA nanoparticles results in controlled release of encapsulated drugs and exhibited significantly low cell viability in CNE-1 and HNE-1 cancer cells. F/CDPR-NP significantly prolonged the blood circulation of the encapsulated drugs. The AUC of CDDP from F/CDPR-NP (4-fold) was significantly higher compared to that of free CDDP and similarly significantly higher t1/2 for CDDP from F/CDPR-NP was observed. F/CDPR-NP in the presence of laser irradiation showed significant reduction in the tumor burden with low tumor cell proliferations compared to either CDPR-NP or free CDDP indicating the potential of targeted nanoparticles and photodynamic therapy. Overall, combination of treatment modalities and active targeting approach paved way for the higher antitumor activity in nasopharyngeal carcinoma model. The positive results from this study will show new horizon for the treatment of other cancer models.

The role of ablation in the treatment of dysplastic Barrett's esophagus

Endoscopic eradication therapy for Barrett's esophagus has been established as an effective management strategy for patients with Barrett's esophagus with dysplasia and early esophageal cancer. Among the endoscopic therapies, ablation techniques such as radiofrequency ablation and cryoablation are effective primary treatment interventions with acceptable low complication rates forming the spectrum of a multimodal approach. Appropriate selection of patients, high-definition endoscopic evaluation, and dedicated histological assessment are important cornerstones to help navigate to the best effective treatment method. Carefully structured surveillance programs and preventive measures will be needed to provide long-term durability for maintaining complete remission.

DIAGNOSIS, TREATMENT AND FOLLOW-UP OF BARRETT'S ESOPHAGUS: A SYSTEMATIC REVIEW

BACKGROUND

Barrett's esophagus (BE) is a premalignant condition that raises controversy among general practitioners and specialists, especially regarding its diagnosis, treatment, and follow-up protocols.

OBJECTIVE

This systematic review aims to present the particularities and to clarify controversies related to the diagnosis, treatment and surveillance of BE.

METHODS

A systematic review was conducted on PubMed, Cochrane, and SciELO based on articles published in the last 10 years. PRISMA guidelines were followed and the search was made using MeSH and non-MeSH terms "Barrett" and "diagnosis or treatment or therapy or surveillance". We searched for complete randomized controlled clinical trials or Phase IV studies, carried out with individuals over 18 years old.

RESULTS

A total of 42 randomized controlled trials were selected after applying all inclusion and exclusion criteria. A growing trend of alternative and safer techniques to traditional upper gastrointestinal endoscopy were identified, which could improve the detection of BE and patient acceptance. The use of chromoendoscopy-guided biopsy protocols significantly reduced the number of biopsies required to maintain similar BE detection rates. Furthermore, the value of BE chemoprophylaxis with esomeprazole and acetylsalicylic acid was relevant, as well as the establishment of protocols for the follow-up and endoscopic surveillance of patients with BE based predominantly on the presence and degree of dysplasia, as well as on the length of the follow-up affected by BE.

CONCLUSION

Although further studies regarding the diagnosis, treatment and follow-up of BE are warranted, in light of the best evidence presented in the last decade, there is a trend towards electronic chromoendoscopy-guided biopsies for the diagnosis of BE, while treatment should encompass endoscopic techniques such as radiofrequency ablation. Risks of ablative endoscopic methods should be weighted against those of resective surgery. It is also important to consider lifetime endoscopic follow-up for both short and long term BE patients, with consideration to limitations imposed by a range of comorbidities. Unfortunately, there are no randomized controlled trials that have evaluated which is the best recommendation for BE follow-up and endoscopic surveillance (>1 cm) protocols, however, based on current International Guidelines, it is recommended esophagogastroduodenoscopy (EGD) every 5 years in BE without dysplasia with 1 up to 3 cm of extension; every 3 years in BE without dysplasia with >3 up to 10 cm of extension, every 6 to 12 months in BE with low grade dysplasia and, finally, EGD every 3 months after ablative endoscopic therapy in cases of BE with high grade dysplasia.

Efficacy of 5-aminolevulinic acid-mediated photodynamic therapy in a mouse model of esophageal cancer

5-Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is a minimally invasive therapeutic modality used in the management of various cancers, but to a lesser extent for esophageal cancer (EC). The current study investigated the antitumor effects of ALA-PDT. Human EC cells were treated with ALA, after which ALA-induced fluorescence was examined under a fluorescence microscope. The cytotoxic effects of ALA-PDT were assessed using three types of LEDs (blue, green and red) in vitro and in vivo. Subcutaneous tumor model mice was constructed with KYSE150 cells. ALA-PDT was performed once a week for 4 weeks and tumor weights were measured. A popliteal lymph node (PLN) metastasis murine model was generated using KYSE150 cells. KYSE150 cells were inoculated into the left footpad of nude mice. ALA-PDT was performed on the footpad once a week for 4 weeks. PLNs were then removed 3 weeks after the last treatment. The lymph nodes were evaluated by hematoxylin and eosin staining. Red fluorescence of protoporphyrin IX (PpIX) was observed in all EC cell lines. ALA-PDT using LEDs exerted significant antitumor effects in vitro and in vivo. The antitumor effects of ALA-PDT with blue LED were the strongest, followed by green and red LEDs. The number of metastasized PLNs was significantly smaller in the ALA-PDT group (0%) than in the control group (37.5%). The present results indicated that ALA-PDT is effective for EC.

Indications, contraindications and limitations of endoscopic therapy for Barrett's esophagus and early esophageal adenocarcinoma

Endoscopic eradication therapy (EET) has revolutionized management of Barrett's esophagus (BE)-associated neoplasia, traditionally treated by esophagectomy, which carries very high mortality and morbidity. EET, usually performed in the outpatient setting, has a safe risk profile. It is indicated in patients with BE with high-grade dysplasia and intramucosal cancer, confirmed, and persistent low-grade dysplasia, and in highly selected cases of non-dysplastic BE and submucosal cancers. Multiple EET modalities are available and can be categorized into two groups: ablation therapies and resection techniques with resection techniques usually reserved for nodular/raised lesions or lesions with suspected neoplasia. Patients usually require multiple ablation sessions with a goal of achieving complete eradication of metaplasia. Despite very good results, EET has its limitations and is not 100% effective: it targets a small subset of patients along the spectrum of BE and esophageal adenocarcinoma, as most patients with esophageal adenocarcinoma remain asymptomatic until the disease has progressed to advanced stages. Post-ablation surveillance is mandatory, as recurrences are common. An area of concern is buried metaplasia reported to occur following ablation therapy and thought to be from de novo growth of metaplastic tissue underneath the neosquamous epithelium, following ablation. The focus of this review article is to present the indications, contraindications and limitations of EET.

Endoscopic therapy for Barrett’s esophagus and early esophageal cancer: Where do we go from here?

Since Barrett’s esophagus is a precancerous condition, efforts have been made for its eradication by various ablative techniques. Initially, laser ablation was attempted in non-dysplastic Barrett’s esophagus and subsequently, endoscopic ablation using photodynamic therapy was used in Barrett’s patients with high-grade dysplasia who were poor surgical candidates. Since then, various ablative therapies have been developed with radiofrequency ablation having the best quality of evidence. Resection of dysplastic areas only without complete removal of entire Barrett’s segment is associated with high risk of developing metachronous neoplasia. Hence, the current standard of management for Barrett’s esophagus includes endoscopic mucosal resection of visible abnormalities followed by ablation to eradicate remaining Barrett’s epithelium. Although endoscopic therapy cannot address regional lymph node metastases, such nodal involvement is present in only 1% to 2% of patients with intramucosal adenocarcinoma in Barrett esophagus and therefore is useful in intramucosal cancers. Post ablation surveillance is recommended as recurrence of intestinal metaplasia and dysplasia have been reported. This review includes a discussion of the technique, efficacy and complication rate of currently available ablation techniques such as radiofrequency ablation, cryotherapy, argon plasma coagulation and photodynamic therapy as well as endoscopic mucosal resection. A brief discussion of the emerging technique, endoscopic submucosal dissection is also included.

Arene Ruthenium Metalla-Assemblies with Anthracene Moieties for PDT Applications

The synthesis and characterization of three metalla-rectangles of the general formula [Ru4(η6-p-cymene)4(μ4-clip)2(μ2-Lanthr)2][CF3SO3]4 (Lanthr: 9,10-bis(3,3’-ethynylpyridyl) anthracene; clip = oxa: oxalato; dobq: 2,5-dioxido-1,4-benzoquinonato; donq: 5,8-dioxido-1,4-naphthoquinonato) are presented. The molecular structure of the metalla-rectangle [Ru4(η6-p-cymene)4(μ4-oxa)2(μ2-Lanthr)2]4+ has been confirmed by the single-crystal X-ray structure analysis of [Ru4(η6-p-cymene)4(μ4-oxa)2(μ2-Lanthr)2][CF3SO3]4 · 4 acetone (A2 · 4 acetone), thus showing the anthracene moieties to be available for reaction with oxygen. While the formation of the endoperoxide form of Lanthr was observed in solution upon white light irradiation, the same reaction does not occur when Lanthr is part of the metalla-assemblies.

Oral 5-aminolevulinic acid-mediated photodynamic diagnosis using fluorescence cystoscopy for non-muscle-invasive bladder cancer: A multicenter phase III study

OBJECTIVE

To confirm the reproducibility of the effectiveness and safety in photodynamic diagnosis of non-muscle-invasive bladder cancer using 5-aminolevulinic acid in a prospective multicenter non-randomized phase III trial.

METHODS

A total of 61 patients with primary or recurrent non-muscle-invasive bladder cancer were prospectively enrolled from five hospitals between May 2015 and March 2016. 5-Aminolevulinic acid (20 mg/kg) was orally administered 3 h before transurethral resection of bladder tumors using white light or fluorescent light. Of 60 evaluable patients, 511 specimens were obtained from tumor-suspicious lesions and normal-looking mucosa. The primary end-point was sensitivity. The secondary end-points were specificity, positive and negative predictive values, and safety.

RESULTS

The sensitivity of the fluorescent light source (79.6%) was significantly higher (P < 0.001) than that of the white light source (54.1%). In total, 25.4% (46/181) of tumor specimens were diagnosed as positive with only the fluorescent light source. In nine (15%) of 60 patients, the risk classification and recommended treatment after transurethral resection of bladder tumors were changed depending on the additional types of tumor diagnosed by the fluorescent light source. The specificity of the fluorescent light versus white light source was 80.6% versus 95.5%. No grade 4-5 adverse event was noted. Hypotension and urticaria were severe adverse events whose relationship to oral 5-aminolevulinic acid could not be excluded.

CONCLUSIONS

These findings confirm the diagnostic efficacy and safety of photodynamic diagnosis with 20 mg/kg of oral 5-aminolevulinic acid, and show that transurethral resection of bladder tumors with a fluorescent light source using oral 5-aminolevulinic acid is well tolerated.

UK guidelines on oesophageal dilatation in clinical practice

These are updated guidelines which supersede the original version published in 2004. This work has been endorsed by the Clinical Services and Standards Committee of the British Society of Gastroenterology (BSG) under the auspices of the oesophageal section of the BSG. The original guidelines have undergone extensive revision by the 16 members of the Guideline Development Group with representation from individuals across all relevant disciplines, including the Heartburn Cancer UK charity, a nursing representative and a patient representative. The methodological rigour and transparency of the guideline development processes were appraised using the revised Appraisal of Guidelines for Research and Evaluation (AGREE II) tool.Dilatation of the oesophagus is a relatively high-risk intervention, and is required by an increasing range of disease states. Moreover, there is scarcity of evidence in the literature to guide clinicians on how to safely perform this procedure. These guidelines deal specifically with the dilatation procedure using balloon or bougie devices as a primary treatment strategy for non-malignant narrowing of the oesophagus. The use of stents is outside the remit of this paper; however, for cases of dilatation failure, alternative techniques-including stents-will be listed. The guideline is divided into the following subheadings: (1) patient preparation; (2) the dilatation procedure; (3) aftercare and (4) disease-specific considerations. A systematic literature search was performed. The Grading of Recommendations Assessment, Develop-ment and Evaluation (GRADE) tool was used to evaluate the quality of evidence and decide on the strength of recommendations made.

Long-term outcomes of the randomized controlled trial comparing 5-aminolaevulinic acid and Photofrin photodynamic therapy for Barrett's oesophagus related neoplasia

OBJECTIVE

Photodynamic therapy (PDT) was used as therapy for early neoplasia associated with Barrett's oesophagus (BE). This is 5-year follow-up of patients enrolled into randomised controlled trial of 5-aminolaevulinic acid (ALA) vs. Photofrin PDT.

METHODS

Biopsies were taken from original Barrett's segment during endoscopic follow up using Seattle protocol. Endoscopic mucosal resection (EMR) ± radiofrequency ablation (RFA) was preferred therapy in patients who failed PDT and/or had recurrent neoplasia.

RESULTS

Fifty eight of 64 patients enrolled in the original trial were followed up including 31 patients treated with ALA PDT (17 patients with ≤6 cm, 14 patients with >6 cm segment of BE) and 27 treated with Photofrin PDT (14 patients with ≤6 cm, 13 patients with >6 cm BE). Initial success was achieved in 65% (20/31) ALA and 48% (13/27) Photofrin patients (p = .289). Thirty five percent patients (7/20) relapsed in ALA group and 54% (7/13) relapsed in Photofrin group (p = .472). At a median follow-up of 67 months, no significant difference was found in long-term complete reversal of intestinal metaplasia (CR-IM) and complete reversal of dysplasia (CR-D) between ALA and Photofrin groups (78% vs. 63%; p = .18; 90% vs. 76%; p = .26). Original length of BE did not alter long-term outcome. Four patients from each group progressed to invasive oesophageal adenocarcinoma. Initial success of ALA PDT was associated with significantly better likelihood of long-term remission (p = .03).

CONCLUSIONS

Initial response to PDT plays key role in long term outcome. RFA ± EMR have, however, become preferred minimally invasive ablative therapy for BE-related neoplasia due to poor efficacy of PDT.

Protoporphyrinogen oxidase is involved in the fluorescence intensity of 5-aminolevulinic acid-mediated laser-based photodynamic endoscopic diagnosis for early gastric cancer

BACKGROUND/AIM

Laser-based photodynamic endoscopic diagnosis (LPDED) is a type of endoscopic diagnosis that uses the fluorescence caused by the photochemical reaction that occurs when a fluorescent substance is irradiated by a light of a specific wavelength. Although 5-aminolevulinic acid (5-ALA) can detect early gastric cancer (EGC) during LPDED, there is an unresolved issue of the differences in fluorescence intensity among histopathological types of gastric cancer. Thus, the aim of the present study was to assess whether protoporphyrinogen oxidase (PPOX), involved in the activation of protoporphyrin IX, can affect the fluorescence intensity in EGC.

METHODS

Thirty-three gastric tumor lesions in 30 patients were assessed by LPDED using a prototype endoscope equipped with a blue laser ray to cause excitation following oral 5-ALA administration. The tumors were then resected by endoscopic submucosal dissection or laparoscopic surgery. PPOX expression was examined immunohistochemically in the excised specimens. To explore the mechanisms of histopathological diversity in PPOX and coproporphyrinogen oxidase (CPOX) expression of EGC, immunohistochemical analysis was performed using 75 surgically resected specimens of diverse EGCs.

RESULTS

Among the 33 lesions, 26 tumors were detectable by LPDED, whereas seven were undetectable. Between the LPDED-positive and negative groups, there was a significant difference in histopathology. The expression of PPOX was higher in tubular adenocarcinoma (tub) than in signet-ring cell carcinoma (sig). There were significant differences in PPOX and CPOX expression scores of the surgically resected specimens among tub, poorly differentiated adenocarcinoma (por), and sig.

CONCLUSION

PPOX protein expression could be involved in the fluorescence intensity of LPDED in EGC, possibly reflecting histopathological features.

Upregulation of mucin glycoprotein MUC1 in the progression to esophageal adenocarcinoma and therapeutic potential with a targeted photoactive antibody-drug conjugate

BACKGROUND

Mucin glycoprotein 1 (MUC1) is a glycosylated transmembrane protein on epithelial cells. We investigate MUC1 as a therapeutic target in Barrett's epithelium (BE) and esophageal adenocarcinoma (EA) and provide proof of concept for a light based therapy targeting MUC1.

RESULTS

MUC1 was present in 21% and 30% of significantly enriched pathways comparing BE and EA to squamous epithelium respectively. MUC1 gene expression was x2.3 and x2.2 higher in BE (p=<0.001) and EA (p=0.03). MUC1 immunohistochemical expression increased during progression to EA and followed tumor invasion. HuHMFG1 based photosensitive antibody drug conjugates (ADC) showed cell internalization, MUC1 selective and light-dependent cytotoxicity (p=0.0006) and superior toxicity over photosensitizer alone (p=0.0022).

METHODS

Gene set enrichment analysis (GSEA) evaluated pathways during BE and EA development and quantified MUC1 gene expression. Immunohistochemistry and flow cytometry evaluated the anti-MUC1 antibody HuHMFG1 in esophageal cells of varying pathological grade. Confocal microscopy examined HuHMFG1 internalization and HuHMFG1 ADCs were created to deliver a MUC1 targeted phototoxic payload.

CONCLUSIONS

MUC1 is a promising target in EA. Molecular and light based targeting of MUC1 with a photosensitive ADC is effective in vitro and after development may enable treatment of locoregional tumors endoscopically.

Oncologic Photodynamic Therapy: Basic Principles, Current Clinical Status and Future Directions

Photodynamic therapy (PDT) is a clinically approved cancer therapy, based on a photochemical reaction between a light activatable molecule or photosensitizer, light, and molecular oxygen. When these three harmless components are present together, reactive oxygen species are formed. These can directly damage cells and/or vasculature, and induce inflammatory and immune responses. PDT is a two-stage procedure, which starts with photosensitizer administration followed by a locally directed light exposure, with the aim of confined tumor destruction. Since its regulatory approval, over 30 years ago, PDT has been the subject of numerous studies and has proven to be an effective form of cancer therapy. This review provides an overview of the clinical trials conducted over the last 10 years, illustrating how PDT is applied in the clinic today. Furthermore, examples from ongoing clinical trials and the most recent preclinical studies are presented, to show the directions, in which PDT is headed, in the near and distant future. Despite the clinical success reported, PDT is still currently underutilized in the clinic. We also discuss the factors that hamper the exploration of this effective therapy and what should be changed to render it a more effective and more widely available option for patients.

Esophageal neoplasia arising from subsquamous buried glands after an apparently successful photodynamic therapy or radiofrequency ablation for Barrett's associated neoplasia

OBJECTIVE

Photodynamic therapy (PDT) and radiofrequency ablation (RFA) are effective non-surgical options for the treatment of Barrett's esophagus (BE) associated neoplasia. Development of subsquamous intestinal metaplasia after successful PDT and/or RFA is a recognized phenomenon; however, the occurrence of neoplasia arising from buried glands is a rare complication.

METHODS

This is a prospective case series of patients treated with PDT and/or RFA from 1999 to 2014 at University College London Hospital for neoplasia associated with BE, whose outcomes were analyzed retrospectively. Prior to any ablative therapy any visible nodularity was removed with endoscopic mucosal resection (EMR). After successful PDT and/or HALO RFA treatment, defined as a complete reversal of dysplasia and metaplasia, patients underwent endoscopic follow up using the Seattle protocol.

RESULTS

A total of 288 patients were treated, 91 with PDT between 1999 and 2010, 173 with RFA between 2007 and 2014, and 24 with both PDT and RFA for neoplasia associated with BE. Subsquamous neoplasia occurred in seven patients (7/288, 2%). The first patient developed subsquamous invasive adenocarcinoma and underwent curative surgery. Another five patients with subsquamous neoplasia (either high-grade dysplasia or intramucosal cancer) were treated successfully with EMR. The final patient developed subsquamous invasive esophagogastric junctional adenocarcinoma with liver metastases.

CONCLUSION

Development of subsquamous neoplasia after an apparently successful PDT and/or RFA is a rare but recognized complication. Clinicians should be aware of this phenomenon and have a low threshold for performing an EMR. Thorough surveillance following successful PDT and/or RFA ensuring high-quality endoscopy is required.

Management of Barrett's esophagus: From screening to newer treatments

Barrett's esophagus is a premalignant condition of the esophagus in which the squamous epithelium of the lower end of the esophagus is replaced with columnar epithelium. Since the incidence of esophageal adenocarcinoma is on the rise, the major gastroenterology societies have come up with their recommendations for screening and surveillance. Specific factors like obesity, white race, age over 50 years, early age of onset of GERD, smoking and hiatal hernia have been identified as increasing the risk of Barrett's esophagus and adenocarcinoma. The diagnosis requires both endoscopic identification of columnar-lined mucosa and histological confirmation with biopsy. Most medical societies recommend screening people with GERD and other risk factors with endoscopy, but other alternatives employing less invasive methods are currently being studied. Surveillance strategies vary depending on the endoscopic findings and the Seattle biopsy protocol with random 4-quadrant sampling is recommended. Biomarkers have shown promising results, but more studies are needed in the future. White light endoscopy is the standard practice, but other advanced imaging modalities have shown variable results and hence more studies are awaited for further validation. Endoscopic eradication techniques, including both resection and ablation, have shown good but variable results for treating dysplastic lesions confined to the mucosa. Resection procedures to remove visible lesions followed by ablation of the dysplastic mucosa have shown the best results with higher eradication rates and lower recurrence rates. Surgical management is reserved for lesions with sub-mucosal invasion and lymph node spread with increased risk of metastasis.

Management of Barrett's oesophagus

Barrett's oesophagus is associated with the development of oesophageal adenocarcinoma. This review highlights the management strategies currently used in the treatment of this condition.

Endoscopic treatments for dysplastic Barrett's esophagus: resection, ablation, what else?

BACKGROUND

Endoscopic eradication therapy for dysplastic Barrett's esophagus (BE) comprises resection and mucosal ablation techniques. Over the years, these techniques have been tried with success, not only for dysplastic Barrett's epithelium but also for non-dysplastic Barrett's epithelium and early adenocarcinoma. Endoscopic resection is usually carried out for visible lesions, either as endoscopic mucosal resection (EMR), which is practiced widely in Western countries, or as endoscopic submucosal dissection, which is more popular in Japan and throughout Asia. Among ablative techniques are photodynamic therapy, cryotherapy, and radiofrequency ablation (RFA).

METHODS

We reviewed the published evidence pertaining to endoscopic treatments of dysplastic BE, with emphasis on the various resection and ablative techniques, their safety, efficacy, durability of effect, and tolerability.

RESULTS

Both resection and ablation procedures performed endoscopically have been proved effective, and safe for treating dysplastic BE and early adenocarcinoma. Among the ablative techniques, RFA has shown to be more effective and safe, and is preferred for most cases.

CONCLUSIONS

Endoscopic therapies have revolutionized the treatment of BE and have minimized the need for surgical intervention in many patients. Concomitant treatment of acid reflux with proton pump inhibitors and continuous surveillance are essential. Combination techniques such as EMR followed by RFA may be also considered in some cases.

Ablative Endoscopic Therapies for Barrett's-Esophagus-Related Neoplasia

Barrett's esophagus (BE) is more common in developed countries. Endoscopic therapy is an effective treatment method in management of dysplastic BE. Ablation by thermal energy, freezing, or photochemical injury completely eradicates dysplasia and specialized intestinal metaplasia resulting in neosquamation of esophagus. Among the ablative modalities, radiofrequency ablation (RFA) is the most studied with safe, effective, and durable long-term outcomes. Cryotherapy, argon plasma coagulation, and photodynamic therapy can be offered in select patients when RFA is unavailable, has failed, or is contraindicated. Future research on natural disease progression, biomarkers, advanced imaging, and application of endoscopic techniques will lead to better clinical outcomes for BE-associated neoplasia.

Self-assembled core-shell nanoparticles for combined chemotherapy and photodynamic therapy of resistant head and neck cancers

Combination therapy enhances anticancer efficacy of both drugs via synergistic effects. We report here nanoscale coordination polymer (NCP)-based core-shell nanoparticles carrying high payloads of cisplatin and the photosensitizer pyrolipid, NCP@pyrolipid, for combined chemotherapy and photodynamic therapy (PDT). NCP@pyrolipid releases cisplatin and pyrolipid in a triggered manner to synergistically induce cancer cell apoptosis and necrosis. In vivo pharmacokinetic and biodistribution studies in mice show prolonged blood circulation times, low uptake in normal organs, and high tumor accumulation of cisplatin and pyrolipid. Compared to monotherapy, NCP@pyrolipid shows superior potency and efficacy in tumor regression (83% reduction in tumor volume) at low drug doses in the cisplatin-resistant human head and neck cancer SQ20B xenograft murine model. We elucidated the in vitro/vivo fate of the lipid layer and its implications on the mechanisms of actions. This study suggests multifunctional NCP core-shell nanoparticles as a versatile and effective drug delivery system for potential translation to the clinic.

Endoscopic assessment and management of early esophageal adenocarcinoma

Esophageal carcinoma affects more than 450000 people worldwide and the incidence is rapidly increasing. In the United States and Europe, esophageal adenocarcinoma has superseded esophageal squamous cell carcinoma in its incidence. Esophageal cancer has a high mortality rates secondary to the late presentation of most patients at advanced stages. Endoscopic screening is recommended for patients with multiple risk factors for cancer in Barrett’s esophagus. These risk factors include chronic gastroesophageal reflux disease, hiatal hernia, advanced age, male sex, white race, cigarette smoking, and obesity. The annual risk of esophageal cancer is approximately 0.25% for patients without dysplasia and 6% for patients with high-grade dysplasia. Twenty percent of all esophageal adenocarcinoma in the United States is early stage with disease confined to the mucosa or submucosa. The significant morbidity and mortality of esophagectomy make endoscopic treatment an attractive option. The American Gastroenterological Association recommends endoscopic eradication therapy for patients with high-grade dysplasia. Endoscopic modalities for treatment of early esophageal adenocarcinoma include endoscopic resection techniques and endoscopic ablative techniques such as radiofrequency ablation, photodynamic therapy and cryoablation. Endoscopic therapy should be precluded to patients with no evidence of lymphovascular invasion. Local tumor recurrence is low after endoscopic therapy and is predicted by poor differentiation of tumor, positive lymph node and submucosal invasion. Surgical resection should be offered to patients with deep submucosal invasion.

Treatment of dysplasia in barrett esophagus

Barrett esophagus is recognized as a risk factor for the development of dysplasia and adenocarcinoma of the esophagus. Cancer is usually diagnosed at an advanced stage with a 5-year survival rate of 15%. Most of these patients present de novo and are not part of a surveillance program. Endoscopic screening with improvement in recognition of early lesions may change this pattern. In the past, patients diagnosed with dysplasia and mucosal cancer were best managed by esophagectomy. Endoscopic techniques such as endoscopic mucosal resection and radiofrequency ablation have resulted in high curative rates and a shift away from esophagectomy. This pathway is supported by the literature review of esophagectomies performed for mucosal disease, as well as pathologists' interpretation of endoscopic mucosal specimens, which document the low risk of lymph node metastasis. The role of endoscopic therapy for superficial submucosal disease continues to be a challenge.

Block copolymer nanoassemblies for photodynamic therapy and diagnosis

Light can be a powerful therapeutic and diagnostic tool. Light-sensitive molecules can be used to develop locally targeted cancer therapeutics. This approach is known as photodynamic therapy (PDT). Similarly, it is possible to diagnose diseases and track the course of treatment in vivo using ligh-sensitive molecules. This methodology is referred to as photodynamic diagnosis (PDD). Despite the potential, many PDT and PDD agents have imperfect physiochemical properties for their successful clinical application. Nanotechnology may solve these issues by improving the viability of PDT and PDD. This review summarizes the current state of PDT and PDD development, the integration of nanotechnology in the field, and the prospective future applications, demonstrating the potential of PDT and PDD for improved cancer treatment and diagnosis.

Safe ablation of the anal mucosa and perianal skin in rats using Photodynamic Therapy--a promising approach for treating Anal Intraepithelial Neoplasia

BACKGROUND

Anal Intraepithelial Neoplasia (AIN), a pre-cursor of anal squamous carcinoma, is increasingly detected in individuals with impaired immune function. However, choices for effective, low morbidity treatment are limited. Photodynamic Therapy (PDT) is promising as it is known to ablate more proximal gastrointestinal mucosa with safe healing, without damage to underlying muscle. It can also ablate skin with safe healing and minimal scarring.

METHODS

Pharmacokinetics: Normal rats were sensitised with 200mg/kg 5-aminolaevulinic acid (ALA) and killed 1-8h later. Anal tissues were examined by fluorescence microscopy to quantify the concentration of PPIX (protoporphyrin IX, the active derivative of ALA) in anal mucosa and in the underlying sphincter. PDT: Normal rats were sensitised similarly 3h later, laser light (635 nm) was delivered. Anal canal: 50-150 J/cm using 1cm diffuser fibre; for peri-anal skin, 50-200 J/cm(2), using microlens fibre. In each group, 2 rats were killed 3, 7, 14 and 28 days later and the anal region removed for histological examination.

RESULTS

Pharmacokinetics: Peak concentration of PPIX in mucosa was at 3h, peak ratio mucosa: muscle, 6, seen at same time. PDT. Anal canal 50 J/cm: complete mucosal ablation by 3 days, complete regeneration by 28 days. Higher energies caused muscle damage with scarring. Peri-anal skin: 200 J/cm(2); complete ablation of skin, including appendages, complete healing by 28 days. Minimal effect with lower energy.

CONCLUSION

ALA-PDT can ablate anal mucosa and peri-anal skin with safe healing and no underlying damage. However, over treatment can damage the sphincters. This technique is ready to undergo clinical trials.

Endoscopic eradication therapy for mucosal neoplasia in Barrett's esophagus

PURPOSE OF REVIEW

Endoscopic eradication therapy is frequently used to treat dysplasia and early cancers in Barrett's esophagus. This review addresses some of the recent developments in the field of endoscopic eradication therapy for Barrett's esophagus.

RECENT FINDINGS

Data on the effectiveness of Barrett's esophagus ablation programs have been published recently, with excellent results for dysplasia eradication. Studies describing long-term results have shed light on the durability of endoscopic ablation, with recurrence of Barrett's esophagus and neoplasia seen in some cases, particularly at the gastroesophageal junction. Risk factors for failed ablation include longer Barrett's esophagus segments and persistent gastroesophageal reflux. New developments include studies combining radiofrequency ablation (RFA) and endoscopic mucosal resection into a single endoscopic session, endoscopic submucosal dissection for Barrett's esophagus neoplasia, and a simplified RFA algorithm. New data on the cost-effectiveness of RFA have also been published, suggesting that RFA is cost-effective for both high-grade and low-grade dysplasia, but not for nondysplastic Barrett's esophagus. A systematic review has shown that lymph node metastases are rare (∼2%) with intramucosal adenocarcinoma, supporting the use of endoscopic eradication for that lesion.

SUMMARY

Research and clinical experience with the endoscopic therapies for Barrett's esophagus continue to grow. Proper patient selection and technique are critical for ensuring a good outcome. Endoscopic surveillance after any of the ablative therapies still appears to be necessary.

Radiofrequency ablation and endoscopic mucosal resection for dysplastic barrett's esophagus and early esophageal adenocarcinoma: outcomes of the UK National Halo RFA Registry

BACKGROUND & AIMS

Patients with Barrett's esophagus (BE) and high-grade dysplasia (HGD) or early neoplasia increasingly receive endoscopic mucosal resection and radiofrequency ablation (RFA) therapy. We analyzed data from a UK registry that follows the outcomes of patients with BE who have undergone RFA for neoplasia.

METHODS

We collected data on 335 patients with BE and neoplasia (72% with HGD, 24% with intramucosal cancer, 4% with low-grade dysplasia [mean age, 69 years; 81% male]), treated at 19 centers in the United Kingdom from July 2008 through August 2012. Mean length of BE segments was 5.8 cm (range, 1-20 cm). Patients' nodules were removed by endoscopic mucosal resection, and the patients then underwent RFA every 3 months until all areas of BE were ablated or cancer developed. Biopsies were collected 12 months after the first RFA; clearance of HGD, dysplasia, and BE were assessed.

RESULTS

HGD was cleared from 86% of patients, all dysplasia from 81%, and BE from 62% at the 12-month time point, after a mean of 2.5 (range, 2-6) RFA procedures. Complete reversal dysplasia was 15% less likely for every 1-cm increment in BE length (odds ratio = 1.156; SE = 0.048; 95% confidence interval: 1.07-1.26; P < .001). Endoscopic mucosal resection before RFA did not provide any benefit. Invasive cancer developed in 10 patients (3%) by the 12-month time point and disease had progressed in 17 patients (5.1%) after a median follow-up time of 19 months. Symptomatic strictures developed in 9% of patients and were treated by endoscopic dilatation. Nineteen months after therapy began, 94% of patients remained clear of dysplasia.

CONCLUSIONS

We analyzed data from a large series of patients in the United Kingdom who underwent RFA for BE-related neoplasia and found that by 12 months after treatment, dysplasia was cleared from 81%. Shorter segments of BE respond better to RFA; http://www.controlled-trials.com, number ISRCTN93069556.

Photodynamic Therapy for Barrett's Esophagus and Esophageal Carcinoma

This paper reviews the use of photodynamic therapy (PDT) in patients with Barrett's esophagus and esophageal carcinoma. We describe the history of PDT, mechanics, photosensitizers for PDT in patients with esophageal disease. Finally, we discuss its utility and limitations in this setting.

Techniques for fluorescence detection of protoporphyrin IX in skin cancers associated with photodynamic therapy

Photodynamic therapy (PDT) is a treatment modality that uses a specific photosensitizing agent, molecular oxygen, and light of a particular wavelength to kill cells targeted by the therapy. Topically administered aminolevulinic acid (ALA) is widely used to effectively treat cancerous and precancerous skin lesions, resulting in targeted tissue damage and little to no scarring. The targeting aspect of the treatment arises from the fact that ALA is preferentially converted into protoporphyrin IX (PpIX) in neoplastic cells. To monitor the amount of PpIX in tissues, techniques have been developed to measure PpIX-specific fluorescence, which provides information useful for monitoring the abundance and location of the photosensitizer before and during the illumination phase of PDT. This review summarizes the current state of these fluorescence detection techniques. Non-invasive devices are available for point measurements, or for wide-field optical imaging, to enable monitoring of PpIX in superficial tissues. To gain access to information at greater tissue depths, multi-modal techniques are being developed which combine fluorescent measurements with ultrasound or optical coherence tomography, or with microscopic techniques such as confocal or multiphoton approaches. The tools available at present, and newer devices under development, offer the promise of better enabling clinicians to inform and guide PDT treatment planning, thereby optimizing therapeutic outcomes for patients.