Systematic review: photodynamic therapy for unresectable cholangiocarcinoma

Enhancing Cancer Treatment Through Combined Approaches: Photodynamic Therapy in Concert with Other Modalities

This review explores the role of photodynamic therapy (PDT) as an adjunctive treatment for cancers, with a focus on its potential to enhance the effects of established therapies like chemotherapy, surgery, and radiotherapy. Given the limitations of conventional cancer treatments, PDT's ability to improve therapeutic outcomes through combination strategies is examined. In cancers such as lung, breast, cholangiocarcinoma, and cervical, PDT shows promise in enhancing response rates, reducing recurrence, and minimizing adverse effects when used alongside standard modalities. This study highlights current findings on PDT's mechanisms in complementing chemotherapy, augmenting surgical precision, and enhancing radiotherapeutic effects, thus offering a multi-faceted approach to cancer treatment. Additionally, insights into the clinical application of PDT in these cancers emphasize its potential for reducing tumor resistance and supporting more effective, personalized care. By providing an overview of PDT's synergistic applications across diverse cancer types, this review underscores its emerging significance in oncology as a tool to address traditional treatment limitations. Ultimately, this review aims to inform and inspire researchers and clinicians seeking to refine and innovate cancer therapy strategies through PDT integration, contributing to the advancement of more effective, synergistic cancer treatments.

Chinese national clinical practice guideline on diagnosis and treatment of biliary tract cancers

BACKGROUND

Biliary tract carcinoma (BTC) is relatively rare and comprises a spectrum of invasive tumors arising from the biliary tree. The prognosis is extremely poor. The incidence of BTC is relatively high in Asian countries, and a high number of cases are diagnosed annually in China owing to the large population. Therefore, it is necessary to clarify the epidemiology and high-risk factors for BTC in China. The signs associated with BTC are complex, often require collaborative treatment from surgeons, endoscopists, oncologists, and radiation therapists. Thus, it is necessary to develop a comprehensive Chinese guideline for BTC.

METHODS

This clinical practice guideline (CPG) was developed following the process recommended by the World Health Organization. The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess the certainty of evidence and make recommendations. The full CPG report was reviewed by external guideline methodologists and clinicians with no direct involvement in the development of this CPG. Two guideline reporting checklists have been adhered to: Appraisal of Guidelines for Research and Evaluation (AGREE) and Reporting Items for practice Guidelines in Healthcare (RIGHT).

RESULTS

The guideline development group, which comprised 85 multidisciplinary clinical experts across China. After a controversies conference, 17 clinical questions concerning the prevention, diagnosis, and treatment of BTC were proposed. Additionally, detailed descriptions of the surgical principles, perioperative management, chemotherapy, immunotherapy, targeted therapy, radiotherapy, and endoscopic management were proposed.

CONCLUSIONS

The guideline development group created a comprehensive Chinese guideline for the diagnosis and treatment of BTC, covering various aspects of epidemiology, diagnosis, and treatment. The 17 clinical questions have important reference value for the management of BTC.

The advancements and prospective developments in anti-tumor targeted therapy

Cancer poses a major threat to human health worldwide. The development of anti-tumor materials provides new modalities for cancer diagnosis and treatment. In this review, we comprehensively summarize the research progress and clinical applications of anti-tumor materials. First, we introduce the etiology and pathogenesis of cancer, and the significance and challenges of anti-tumor materials research. Then, we classify anti-tumor materials and discuss their mechanisms of action. After that, we elaborate the research advances and clinical applications of anti-tumor materials, including those targeting tumor cells and therapeutic instruments. Finally, we discuss the future perspectives and challenges in the field of anti-tumor materials. This review aims to provide an overview of the current status of anti-tumor materials research and application, and to offer insights into future directions in this rapidly evolving field, which holds promise for more precise, efficient and customized treatment of cancer.

Focal Cryo-Immunotherapy with Intratumoral IL-12 Prevents Recurrence of Large Murine Tumors

Focal ablation technologies are routinely used in the clinical management of inoperable solid tumors but they often result in incomplete ablations leading to high recurrence rates. Adjuvant therapies, capable of safely eliminating residual tumor cells, are therefore of great clinical interest. Interleukin-12 (IL-12) is a potent antitumor cytokine that can be localized intratumorally through coformulation with viscous biopolymers, including chitosan (CS) solutions. The objective of this research was to determine if localized immunotherapy with a CS/IL-12 formulation could prevent tumor recurrence after cryoablation (CA). Tumor recurrence and overall survival rates were assessed. Systemic immunity was evaluated in spontaneously metastatic and bilateral tumor models. Temporal bulk RNA sequencing was performed on tumor and draining lymph node (dLN) samples. In multiple murine tumor models, the addition of CS/IL-12 to CA reduced recurrence rates by 30-55%. Altogether, this cryo-immunotherapy induced complete durable regression of large tumors in 80-100% of treated animals. Additionally, CS/IL-12 prevented lung metastases when delivered as a neoadjuvant to CA. However, CA plus CS/IL-12 had minimal antitumor activity against established, untreated abscopal tumors. Adjuvant anti-PD-1 therapy delayed the growth of abscopal tumors. Transcriptome analyses revealed early immunological changes in the dLN, followed by a significant increase in gene expression associated with immune suppression and regulation. Cryo-immunotherapy with localized CS/IL-12 reduces recurrences and enhances the elimination of large primary tumors. This focal combination therapy also induces significant but limited systemic antitumor immunity.

Development of novel biliary metal stent with coil-spring structure and its application in vivo swine biliary stricture model

Background

As of date, endoscopic biliary stenting with plastic stent (PS) and self-expandable metal stent (SEMS) have been widely used for the palliation of biliary tract strictures. However, these two stents have several limitations regarding the management of biliary strictures caused by intrahepatic and hilar cholangiocarcinoma. PS has short patency and also risks bile duct injury and bowel perforation. SEMS is difficult to revise when occluded by tumor overgrowth. To compensate for such shortcomings, we developed a novel biliary metal stent with coil-spring structure. The aim of this study was to investigate the feasibility and efficacy of the novel stent in a swine model.

Methods

The biliary stricture model was prepared in six mini-pigs using endobiliary radiofrequency ablation. Conventional PS (n=2) and novel stents (n=4) were deployed endoscopically. Technical success was defined as successful stent placement and clinical success was defined as >50% reduction of serum bilirubin level. Adverse events, stent migration, and endoscopic removability for one month after stenting were also assessed.

Results

The biliary stricture was successfully created in all animals. The technical success rate was 100 %, and the clinical success rate was 50% in the PS group and 75% in the novel stent group. In the novel stent group, the median pre- and post-treatment serum bilirubin levels were 3.94 and 0.3 mg/dL. Stent migration occurred in two pigs and two stents were removed by endoscopy. There was no stent-related mortality.

Conclusions

The newly designed biliary metal stent was feasible and effective in a swine biliary stricture model. Further studies are needed to verify the usefulness of the novel stent in the management of biliary strictures.

Long-term efficacy of percutaneous transhepatic cholangioscopy-guided photodynamic therapy for postoperative recurrent extrahepatic cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma recurs frequently following excision surgery and is usually inoperable, while radiotherapy, chemotherapy, and immunotherapy are of limited benefit. As palliative care, percutaneous transhepatic cholangial drainage (PTCD) can relieve biliary obstruction, prevent jaundice, and maintain quality of life (QOL), but does not improve overall survival. In contrast, photodynamic therapy (PDT) has been demonstrated to prolong the survival of inoperable cancer patients.

OBJECTIVE

This study evaluated the clinical efficacy of percutaneous transhepatic cholangioscopy (PTCS)-guided PDT following PTCD versus PTCD alone for recurrent inoperable cholangiocarcinoma.

METHODS

The case files of 39 patients with postoperative recurrence were retrospectively analyzed, including 18 receiving PTCS-guided PDT (PTCS-PDT group) and 21 receiving PTCD only as a control (PTCD group). Survival time was compared by Kaplan-Meier analysis and log-rank test, and QOL by the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-HEP) questionnaire. Clinicodemographic factors, including serum bilirubin and adverse reaction rates, were compared by Student's t-test or Fisher's exact test. The maximum follow-up period was 71 months.

RESULTS

Median survival time was significantly longer in the PTCS-PDT group than the PTCD group (23 months vs. 10 months, P = 0.00001). At 6 and 12 months post-treatment, total FACT-HEP score was lower in the PTCS-PDT group (P < 0.05), indicating improved QOL. There was no significant difference in total adverse events incidence between groups (19 [51.4%] vs. 15 [71.4%]; P = 0.131).

CONCLUSION

PTCS-guided PDT can prolong survival and improve the QOL of patients with postoperative cholangiocarcinoma recurrence without increasing complications.

SIGNIFICANT AND/OR NEW FINDINGS

Compared to PTCD alone, PTCS-guided PDT significantly prolonged the survival time of patients with postoperative recurrent extrahepatic cholangiocarcinoma. Photodynamic therapy also improved patient quality of life by facilitating timely removal of the PTCD drainage tube. PTCS-guided PDT did not increase surgery-related complications except for skin phototoxicity, which can be easy avoided and treated.

Comparing palliative treatment options for cholangiocarcinoma: photodynamic therapy vs. radiofrequency ablation

Referral to an endoscopist is often done once curative resection is no longer an option for cholangiocarcinoma management. In such cases, palliation has become the main objective of the treatment. Photodynamic therapy and radiofrequency ablation can be performed to achieve palliation, with both procedures associated with improved stent patency and survival. Despite the greatly increased cost and association with photosensitivity, photodynamic therapy allows transmission to the entire biliary tree. In contrast, radiofrequency ablation is cheaper and faster to apply, but requires intraductal contact. This paper reviews both modalities and compares their efficacy and safety for bile duct cancer palliation.

Endoscopic Management of Pancreatobiliary Malignancies

Pancreatobiliary malignancies have poor prognosis, and many patients are inoperable at the time of diagnosis. When surgical resection is impossible, systemic chemotherapy or radiotherapy is traditionally conducted with trial of immunotherapy or gene therapy lately. With the rapid development of endoscopic instruments and accessories in recent years, not only endoscopic early detection, characterization, and staging but also endoscopic palliative management of the pancreatobiliary malignancies is expanding the horizons. Endoscopic management is often preferred due to similar efficacy to surgical management with less morbidity. Here, we review the methodology and treatment outcome of various endoscopic management strategies in pancreatobiliary malignancies including endoscopic complication management, local palliative therapy, endoscopy-assisted therapy, and pain control utilizing endoscopic retrograde cholangiopancreatography or endoscopic ultrasound.

Smart nanocomposite assemblies for multimodal cancer theranostics

Despite great strides in anticancer research, performance statistics of current treatment modalities remain dismal, highlighting the need for safe, efficacious strategies for tumour mitigation. Non-invasive fusion technology platforms combining photodynamic, photothermal and hyperthermia therapies have emerged as alternate strategies with potential to meet many of the unmet clinical demands in the domain of cancer. These therapies make use of metallic and magnetic nanoparticles with light absorbing properties, which are manipulated to generate either reactive cytotoxic oxygen species or heat for tumour ablation. Combination therapies integrating light, heat and magnetism-mediated nanoplatforms with the conventional approaches of chemotherapy, radiotherapy and surgery are emerging as precision medicine for targeted interventions against cancer. This article aims to compile recent developments of advanced nanocomposite assemblies that integrate multimodal therapeutics for cancer treatment. Amalgamation of various effective, non-invasive technological platforms such as photodynamic therapy (PDT), photothermal therapy (PTT), magnetic hyperthermia (MHT), and chemodynamic therapy (CDT) have tremendous potential in presenting safe and efficacious solutions to the formidable challenges in cancer therapeutics.

Benefits and safety of photodynamic therapy in patients with hilar cholangiocarcinoma: A meta-analysis

BACKGROUND

Photodynamic therapy (PDT) is a therapy evaluated for the treatment of cancers resistant to standard oncological treatments. PDT might be beneficial for the palliation of hilar cholangiocarcinoma.

AIM

To evaluate the efficacy and safety of PDT for treating hilar cholangiocarcinoma.

METHODS

PubMed, Embase, the Cochrane Library, and Web of Science were searched for articles published up to May 2021. The patients were grouped as PDT+stent vs. stent alone. The outcomes were survival, quality of life, and adverse events (AEs). Data were summarized using hazard ratios (HRs), odds ratios (ORs), and 95% confidence intervals (CIs).

RESULTS

Six studies were included in this meta-analysis. There were 235 and 211 patients in the PDT+stent and stent groups, respectively. The 1-year survival rate of the PDT+stent group was 0.56, and that of the control group was 0.25. The 2-year survival rate of the PDT+stent group was 0.16, and that of the control group was 0.07. PDT significantly prolonged overall survival compared to the controls (P = 0.002). No differences were detected in the occurrence of cholangitis (P = 0.996) and all other AEs (early complications, stent malfunction, total AEs, acute pancreatitis, liver abscess, and biliary hemorrhage) between the two groups.

CONCLUSION

PDT in patients with hilar cholangiocarcinoma could improve survival without additional AEs. Large-scale randomized controlled trials are needed to confirm the findings.

Recent Advances in Photodynamic Imaging and Therapy in Hepatobiliary Malignancies: Clinical and Experimental Aspects

The therapeutic and diagnostic modalities of light are well known, and derivative photodynamic reactions with photosensitizers (PSs), specific wavelengths of light exposure and the existence of tissue oxygen have been developed since the 20th century. Photodynamic therapy (PDT) is an effective local treatment for cancer-specific laser ablation in malignancies of some organs, including the bile duct. Although curability for extrahepatic cholangiocarcinoma is expected with surgery alone, patients with unresectable or remnant biliary cancer need other effective palliative therapies, including PDT. The effectiveness of PDT for cholangiocarcinoma has been reported experimentally or clinically, but it is not the standard option now due to problems with accompanied photosensitivity, limited access routes of irradiation, tumor hypoxia, etc. Novel derivative treatments such as photoimmunotherapy have not been applied in the field hepatobiliary system. Photodynamic diagnosis (PDD) has been more widely applied in the clinical diagnoses of liver malignancies or liver vascularization. At present, 5-aminolevulinic acid (ALA) and indocyanine green (ICG) dyes are mainly used as PSs in PDD, and ICG has been applied for detecting liver malignancies or vascularization. However, no ideal tools for combining both PDD and PDT for solid tumors, including hepatobiliary malignancies, have been clinically developed. To proceed with experimental and clinical trials, it is necessary to clarify the effective photosensitive drugs that are feasible for photochemical diagnosis and local treatment.

From molecules to nanovectors: Current state of the art and applications of photosensitizers in photodynamic therapy

Photodynamic therapy (PDT) is a concept based on a selective activation by light of drugs called photosensitizers (PS) leading to reactive oxygen species production responsible for cell destruction. Mechanisms of photodynamic reaction and cell photo-destruction following direct or indirect mechanisms will be presented as well as PS classification, from first generation molecules developed in the 1960 s to third generation vectorized PS with improved affinity for tumor cells. Many clinical applications in dermatology, ophthalmology, urology, gastroenterology, gynecology, neurosurgery and pneumology reported encouraging results in human tumor management. However, this interesting technique needs improvements that are currently investigated in the field of PS excitation by the design of new PS intended for two-photon excitation or for X-ray excitation. The former excitation technique is allowing better light penetration and preservation of healthy tissues while the latter is combining PDT and radiotherapy so that external light sources are no longer needed to generate the photodynamic effect. Nanotechnology can also improve the PS to reach the tumor cells by grafting addressing molecule and by increasing its aqueous solubility and consequently its bioavailability by encapsulation in synthetic or biogenic nanovector systems, ensuring good drug protection and targeting. Co-internalization of PS with magnetic nanoparticles in multifunctional vectors or stealth nanoplatforms allows a theranostic anticancer approach. Finally, a new category of inorganic PS will be presented with promising results on cancer cell destruction.

Effect of endoscopic radiofrequency ablation on the survival of patients with inoperable malignant biliary strictures: A large cohort study

BACKGROUND AND AIMS

Endoscopic radiofrequency ablation (RFA) is an emerging technique for the palliation of inoperable malignant biliary strictures (MBSs). We aimed to systemically investigate the long-term outcome of RFA in a large cohort of patients.

METHODS

We recruited 883 patients with various MBSs who underwent endoscopic interventions at two large-volume centers; 124 patients underwent RFA and stenting, whereas 759 underwent stenting alone. To overcome selection bias, we performed 1:4 propensity score matching (PSM). The main outcome was overall survival (OS).

RESULTS

Following PSM, patients in the RFA group showed significantly longer OS (9.5 months; 95% CI: 7.7-11.3 months) than those in the stenting alone group (6.1 months; 95% CI: 5.6-6.6 months; P < .001). In stratified analyses, the improved OS was only demonstrated in the subgroup of extrahepatic cholangiocarcinoma (11.3 months 95% CI: 10.2-12.4 vs 6.9 months 95% CI: 6.0-7.8; P < .001), but not in the subgroups of gallbladder cancer, hepatocellular carcinoma, intrahepatic cholangiocarcinoma, pancreatic cancer, and other metastatic cancers (all P > .05). The survival benefits were noted only in the patients with non-metastatic cholangiocarcinoma (11.5 vs 7.4 months, P < .001).

CONCLUSIONS

The survival benefits of endoscopic RFA appear to be limited to patients with extrahepatic cholangiocarcinoma without distant metastasis.

Extrahepatic cholangiocarcinoma: Current status of endoscopic approach and additional therapies

The prognosis of patients with advanced or unresectable extrahepatic cholangiocarcinoma is poor. More than 50% of patients with jaundice are inoperable at the time of first diagnosis. Endoscopic treatment in patients with obstructive jaundice ensures bile duct drainage in preoperative or palliative settings. Relief of symptoms (pain, pruritus, jaundice) and improvement in quality of life are the aims of palliative therapy. Stent implantation by endoscopic retrograde cholangiopancreatography is generally preferred for long-term palliation. There is a vast variety of plastic and metal stents, covered or uncovered. The stent choice depends on the expected length of survival, quality of life, costs and physician expertise. This review will provide the framework for the endoscopic minimally invasive therapy in extrahepatic cholangiocarcinoma. Moreover, additional therapies, such as brachytherapy, photodynamic therapy, radiofrequency ablation, chemotherapy, molecular-targeted therapy and/or immunotherapy by the endoscopic approach, are the nonsurgical methods associated with survival improvement rate and/or local symptom palliation.

Progress in Clinical Trials of Photodynamic Therapy for Solid Tumors and the Role of Nanomedicine

Current research to find effective anticancer treatments is being performed on photodynamic therapy (PDT) with increasing attention. PDT is a very promising therapeutic way to combine a photosensitive drug with visible light to manage different intense malignancies. PDT has several benefits, including better safety and lower toxicity in the treatment of malignant tumors over traditional cancer therapy. This reasonably simple approach utilizes three integral elements: a photosensitizer (PS), a source of light, and oxygen. Upon light irradiation of a particular wavelength, the PS generates reactive oxygen species (ROS), beginning a cascade of cellular death transformations. The positive therapeutic impact of PDT may be limited because several factors of this therapy include low solubilities of PSs, restricting their effective administration, blood circulation, and poor tumor specificity. Therefore, utilizing nanocarrier systems that modulate PS pharmacokinetics (PK) and pharmacodynamics (PD) is a promising approach to bypassing these challenges. In the present paper, we review the latest clinical studies and preclinical in vivo studies on the use of PDT and progress made in the use of nanotherapeutics as delivery tools for PSs to improve their cancer cellular uptake and their toxic properties and, therefore, the therapeutic impact of PDT. We also discuss the effects that photoimmunotherapy (PIT) might have on solid tumor therapeutic strategies.

Photodynamic therapy of cancer of large duodenal papilla and extrahepatic bile ducts

The problem of treating patients with malignant neoplasms of the extrahepatic bile ducts and the large duodenal papilla remains relevant due to the growing incidence, high mortality, and a pronounced decrease in the quality of life of patients, despite the radical surgery. The purpose of this study was to evaluate the effectiveness of photodynamic therapy (PDT) in inoperable patients with malignant tumors of these localizations.

The study is based on the treatment of 79 patients with adenocarcinoma of large duodenal papilla and extrahepatic bile ducts. 29 patients received palliative bile drainage operations with PDT. 50 patients in the control group only had palliative bile drainage operations. Patients in the study group received from 1 to 3 PDT courses in a year. In total, 29 patients received 52 PDT courses. The tolerance to the method and the life expectancy of patients were evaluated. The median survival of patients who underwent PDT was 18 months (11–60 months); in the control group – 11.5 months. PDT, in combination with bile drainage operation, is an effective method for the treatment of inoperable patients with malignant neoplasms of the extrahepatic bile ducts and the large duodenal papilla in the absence of severe complications and with easy tolerance to therapy by patients. For the treatment and prolongation of life of patients whose radical surgical treatment is associated with a high risk of death, PDT seems to be the best treatment option. Results of PDT treatment for cancer of this localization are comparable with the results of radical surgeries and exceed those for palliative surgeries.

Photoimmunotherapy targeting biliary-pancreatic cancer with humanized anti-TROP2 antibody

Photoimmunotherapy (PIT) is a new type of tumor‐specific treatment utilizing monoclonal antibody (mAb)‐photosensitizer conjugates and near‐infrared (NIR) light irradiation. One potential PIT target, the type I transmembrane protein TROP2, is expressed at high levels in many cancers, including pancreatic carcinoma (PC) and cholangiocarcinoma (CC), in which its expression is correlated with poor prognosis and tumor aggressiveness. In this study, we assessed the efficacy of PIT utilizing newly developed humanized anti‐TROP2 mAb conjugated to the photosensitizer IR700 (TROP2‐IR700) for PC and CC. Immunohistochemistry on PC and CC tissue microarrays confirmed that TROP2 is overexpressed in about half of PC and CC specimens. Using cultured PC and CC cells, TROP2‐IR700 localized TROP2‐specific and target‐specific cell killing was observed after NIR light irradiation. In addition, TROP2‐IR700 was localized to mouse xenograft tumors expressing TROP2 after intravenous injection. PC and CC xenograft tumor growth was significantly inhibited by TROP2‐targeted PIT relative to controls. The efficacy of TROP2‐targeted PIT in vitro and against xenografted tumors in vivo suggests promise as a therapy for human PC and CC, both of which currently have dismal prognoses and limited therapeutic options.

Endoscopic palliation of biliary obstruction

Advanced pancreaticobiliary malignancy tends to be uncurable at presentation and causes significant morbidity for patients. Palliation for malignant biliary obstruction should be minimally invasive, cost-effective, and aim to improve quality of life of patients. Strategies of endoscopic palliation of malignant biliary obstruction can differ based on sites and degree of biliary obstruction with complex decisions of optimal stent type and placement that involve conscientious planning by a multidisciplinary team.

Endoscopic Retrograde Cholangiopancreatography-Guided Ablation for Cholangiocarcinoma

Most patients with perihilar cholangiocarcinoma present with surgically unresectable disease owing to the insidious nature of this malignancy. Relief of malignant perihilar biliary obstruction is a key aspect of cholangiocarcinoma. Although palliative stenting using uncovered metal stents has been advocated in patients with unresectable malignant perihilar biliary strictures, several endoscopic retrograde cholangiopancreatography-guided ablative modalities have emerged. Palliative photodynamic therapy, radiofrequency ablation, and intraluminal brachytherapy have been associated with improved stent patency and survival, although the ideal treatment approach remains unclear. This article reviews the published evidence for using each of these endobiliary ablative modalities in this difficult-to-treat patient population.

WITHDRAWN: A comparative effectiveness meta-analysis of photodynamic therapy and stent drainage for unresectable cholangiocarcinoma

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New Indications for Endoscopic Radiofrequency Ablation

Radiofrequency ablation (RFA) is a well-established treatment for several benign, premalignant, and malignant disorders. Although the role of RFA has been clearly defined, new indications for luminal and extraluminal applications of endoscopic RFA-directed therapies have emerged. RFA has recently produced promising results in patients with a variety of gastrointestinal and hepatopancreatobiliary pathologies. For example, endoscopic RFA has been used to treat patients with gastric antral vascular ectasia, chronic radiation proctitis, malignant biliary strictures, and ampullary adenomas with intraductal extension. Furthermore, endoscopic ultrasound-guided RFA appears to be an effective, minimally invasive treatment for ablation of solid and cystic lesions-particularly in the pancreas. We review the newer indications for RFA and discuss potential limitations of endoscopic RFA.

Endoscopic Management of Pancreatobiliary Neoplasms

Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) are the mainstays of interventional endoscopic practice. EUS occupies a central role in the diagnosis of pancreatobiliary neoplasms and offers a platform for a wide range of direct tumor therapies. Initial steps have demonstrated the feasibility of such applications in animal models and pilot studies. Larger clinical trials and incorporation of EUS-based therapies into cooperative cancer studies might demonstrate an impact in the clinical prognosis of patients with pancreatic cancer. ERCP plays an important role in elucidating indeterminate biliary strictures and in treating patients with malignant biliary obstruction who are symptomatic or have borderline-resectable or unresectable disease. ERCP-directed ablative therapies enable neoadjuvant and palliative intervention in patients with malignant biliary obstruction, in particular perihilar cholangiocarcinoma. Additional comparative, multicenter studies are needed to better understand the safety and efficacy of endobiliary brachytherapy, photodynamic therapy, and radiofrequency ablation in patients with pancreatobiliary malignancies.

A novel photodynamic therapy-based drug delivery system layered on a stent for treating cholangiocarcinoma

This study aimed to investigate the drug delivery efficacy and bio-effectiveness of a novel photodynamic therapy (PDT)-matrix drug delivery system for cholangiocarcinoma (CCA). Metallic stents were coated with polyurethane (PU) as the first layer. A 2-hydroxyethyl methacrylate (2-HEMA)/ethylene glycol dimethacrylate (EGDMA)/benzoyl peroxide (BPO) layer and a poly(ethylene-co-vinyl acetate) (PEVA)/poly(n-butyl methacrylate) (PBMA)/polyvinylpyrrolidone K30 (K30) layer containing various concentrations of Photofrin were then incorporated onto the stent as the second and third layers. After incubating the layered membranes with cultured CCA cell line, the release of Photofrin, cell viability, the intracellular uptake of Photofrin, reactive oxygen species (ROS) generation, and apoptosis were determined. Using a single-layer diffusion model, the maximum release of Photofrin from the 5 to 10% K30 formulas was 80 and 100%, respectively, after 24 h. When using the multiple-layer diffusion model, the released Photofrin showed an initial burst of the loading dose from the PEVA/PBMA/K30 layer. In the immobilized model, less than 5% of the Photofrin from the 2-HEMA/EGDMA/BPO layer was released over the 24-h period. Cell viability decreased linearly with increasing Photofrin concentrations, and ROS generation and apoptosis were shown to increase significantly with increasing Photofrin concentrations, until the concentration of Photofrin reached a saturation point of 1.5 μg/ml. This new, multiple-layered, PDT-based stent with dual-release mechanisms is a promising treatment for CCA and cancer-related ductal stenosis.

Success of photodynamic therapy in palliating patients with nonresectable cholangiocarcinoma: A systematic review and meta-analysis

AIM

To perform a systematic review and meta-analysis on clinical outcomes of photodynamic therapy (PDT) in non-resectable cholangiocarcinoma.

METHODS

Included studies compared outcomes with photodynamic therapy and biliary stenting (PDT group) vs biliary stenting only (BS group) in palliation of non-resectable cholangiocarcinoma. Articles were searched in MEDLINE, PubMed, and EMBASE. Pooled proportions were calculated using fixed and random effects model. Heterogeneity among studies was assessed using the I2 statistic.

RESULTS

Ten studies (n = 402) that met inclusion criteria were included in this analysis. The P for χ2 heterogeneity for all the pooled accuracy estimates was > 0.10. Pooled odds ratio for successful biliary drainage (decrease in bilirubin level > 50% within 7days after stenting) in PDT vs BS group was 4.39 (95%CI: 2.35-8.19). Survival period in PDT and BS groups were 413.04 d (95%CI: 349.54-476.54) and 183.41 (95%CI: 136.81-230.02) respectively. The change in Karnofsky performance scores after intervention in PDT and BS groups were +6.99 (95%CI: 4.15-9.82) and -3.93 (95%CI: -8.63-0.77) respectively. Odds ratio for post-intervention cholangitis in PDT vs BS group was 0.57 (95%CI: 0.35-0.94). In PDT group, 10.51% (95%CI: 6.94-14.72) had photosensitivity reactions that were self-limiting. Subgroup analysis of prospective studies showed similar results, except the incidence of cholangitis was comparable in both groups.

CONCLUSION

In palliation of unresectable cholangiocarcinoma, PDT seems to be significantly superior to BS alone. PDT should be used as an adjunct to biliary stenting in these patients.

Treatment of unresectable extrahepatic cholangiocarcinoma using hematoporphyrin photodynamic therapy: A prospective study

BACKGROUND

The available evidence of Photodynamic therapy (PDT) combined with stent placement treatment for unresectable extrahepatic cholangiocarcinoma (EHCC) is still insufficient. It also remains unclear whether PDT influences systemic inflammatory response.

AIM

To explore the clinical efficacy and safety of the combination treatment and the systemic inflammatory response in patients with EHCC.

METHODS

Patients with unresectable EHCC underwent either the combined treatment using Hematoporphyrin PDT and stent placement (PDT+stent group, n=12) or stent-only (stent group, n=27). The primary end-point was overall survival. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels were measured. Quality of life was assessed using the Karnofsky performance scale (KPS) every 3 months.

RESULTS

Average survival time (13.8 vs. 9.6 months), and 6-month (91.7% vs. 74.1%), and 1-year (58.3% vs. 3.7%) survival rates of PDT+stent group were significantly increased compared with the stent group. KPS scores in the PDT+stent group were significantly improved. TNF-α and IL-6 levels were significantly increased in the PDT+stent group.

CONCLUSION

Hematoporphyrin-PDT combined with stent placement is an effective and safe treatment for EHCC. The treatment might promote systemic inflammatory response.

Photodynamic therapy with polyhematoporphyrin for malignant biliary obstruction: A nationwide retrospective study of 150 consecutive applications

BACKGROUND

Photodynamic therapy (PDT) is a palliative treatment for malignant biliary obstruction.

OBJECTIVE

The objective of this article is to assess the feasibility and safety of this technique.

METHODS

In this nationwide, retrospective study of prospectively collected clinical data, all patients treated with PDT using polyhematoporphyrin in Austria from March 2004 to May 2013 were included. Feasibility, adverse events, stent patency and mortality rates were investigated.

RESULTS

Eighty-eight patients (54 male, 34 female, median age 69 years) underwent 150 PDT procedures at seven Austrian referral centers for biliary endoscopy. The predominant underlying disease was Klatskin tumor (79/88). All PDT procedures were feasible without technical issues. Cholangitis was the most frequent adverse event (21/88). Stent patency was 246 days (95% CI 203-289) median and was significantly longer for metal than for plastic stents (269 vs. 62 days, p < 0.01). The median survival was 12.4 months (95% CI 9.7-14.9 m) calculated from first PDT and 15.6 months (95% CI 12.3-18.7 m) calculated from initial diagnosis. In patients suffering from biliary tract cancer, Cox regression revealed the number of PDT treatment sessions as the only independent predictor of survival at a multivariate analysis (p = 0.048).

CONCLUSION

PDT using polyhematoporphyrin was feasible and safe in this nationwide analysis. Survival data suggest a benefit of PDT in this unselected real-life patient population. Prospective trials comparing PDT to other palliative treatments will help to define its role in the management of malignant biliary obstruction. The study is registered at ClinicalTrials.gov number: NCT02504957.

Endoscopic radiofrequency ablation for malignant biliary strictures

Endoscopic radiofrequency ablation (RFA) is a novel palliation therapy for malignant biliary stricture; however, its feasibility and safety has not yet been clearly defined. The aim of the present study was to evaluate the feasibility and safety of endoscopic RFA for the treatment of malignant biliary strictures. A total of 12 patients treated by endoscopic RFA between December 2011 and October 2013 were retrospectively analyzed. Adverse events within 30 days post-intervention, stricture diameters prior to and following RFA, stent patency and survival time were investigated. A total of 12 patients underwent 20 RFA procedures as a treatment for malignant biliary strictures. Two patients required repeated elective RFA (4 and 6 times, respectively). All 20 RFA procedures were successfully performed without technical problems. During a 30 day period following each RFA procedure, two patients experienced fever (38.2 and 38.9°C, respectively) and another patient exhibited post-endoscopic retrograde cholangiopancreatography pancreatitis. The 30- and 90-day mortality rates were 0 and 8.3%, respectively. Mean stricture diameter prior to RFA was 5.3 mm (standard deviation (SD), 0.9 mm; range, 5-8 mm), and the mean diameter following RFA was 12.6 mm (SD, 3.1 mm; range, 8-15 mm). There was a significant increase of 7.3 mm in the bile duct diameter following RFA in comparison with prior to RFA (t=8.6; P≤0.001). Of the 11 patients with stents inserted following RFA, the median stent patency was 125.0 days [95% confidence interval (CI), 94.7-155.3 days]. Extrapolated median survival following the first RFA was 232 days (95% CI, 94.3-369.7 days). In conclusion, RFA appears to be an efficient and safe treatment strategy for the palliation of unresectable malignant biliary strictures.

Cholangiocarcinoma: Current opinion on clinical practice diagnostic and therapeutic algorithms: A review of the literature and a long-standing experience of a referral center

In the oncology landscape, cholangiocarcinoma is a challenging disease in terms of both diagnosis and treatment. Besides anamnesis and clinical examination, a definitive diagnosis of cholangiocarcinoma should be supported by imaging techniques (US, CT, MRI) and invasive investigations (ERC or EUS with brushing and FNA or US or CT-guided biopsy) followed by pathological confirmation. Surgery is the main curative option, so resectability of the tumour should be promptly assessed. Moreover, jaundice must be evaluated at the outset because biliary tract decompression with drainage and stent placement may be required. If the patient is resectable, pre-operative assessment of postoperative liver function is mandatory. After a curative resection, an adjuvant therapy may be administered. Otherwise, in cases with macroscopic residual disease after surgery or locally recurrent or unresectable cholangiocarcinoma at the diagnosis, first-line chemotherapy is the preferred strategy, possibly associated with radiotherapy and/or locoregional treatments. As the diagnostic and therapeutic pathway for cholangiocarcinoma can be declined in different modalities, patients should be promptly referred to a multidisciplinary team in a tertiary centre, familiar with this rare but lethal disease. Hence, the aim of the present paper is to focus on diagnostic and therapeutic algorithms based on the common guidelines and also on the clinical practice of multispecialist expert groups.

A Surgical View of Photodynamic Therapy in Oncology: A Review

Clinical photodynamic therapy (PDT) has existed for over 30 years, and its scientific basis has been known and investigated for well over 100 years. The scientific foundation of PDT is solid and its application to cancer treatment for many common neoplastic lesions has been the subject of a huge number of clinical trials and observational studies. Yet its acceptance by many clinicians has suffered from its absence from the undergraduate and/or postgraduate education curricula of surgeons, physicians, and oncologists. Surgeons in a variety of specialties many with years of experience who are familiar with PDT bear witness in many thousands of publications to its safety and efficacy as well as to the unique role that it can play in the treatment of cancer with its targeting precision, its lack of collateral damage to healthy structures surrounding the treated lesions, and its usage within minimal access therapy. PDT is closely related to the fluorescence phenomenon used in photodiagnosis. This review aspires both to inform and to present the clinical aspect of PDT as seen by a surgeon.

Efficacy and safety of photodynamic therapy for unresectable cholangiocarcinoma: A meta-analysis

BACKGROUND

Photodynamic therapy with the placement of a biliary stent may improve the prognosis in patients with unresectable cholangiocarcinoma. The aim of this research is to determine the hazard ratio of photodynamic therapy with stent compared to biliary stenting alone or other therapies for the treatment of cholangiocarcinoma.

METHODS

Several databases were searched from inception to December 31 2013 for trials comparing photodynamic therapy+stent vs. stent-only or other treatments for cholangiocarcinoma. The outcomes of interest included patient survival, the changes of serum bilirubin levels, the quality of life (Karnofsky performance status), and adverse events. The hazard ratios (HR) were extracted from the survival curves using Tierney's Method. LnHR and its variance were pooled using an inverse variance-weighted average. Inconsistency was quantified using I(2) statistics.

RESULTS

In all, 8 trials comparing PDT+stent with other therapeutic methods were selected. We made a meta-analysis based on the 7 trials, which compared the result of PDT+stent and the stent-only group. HR summarizes the survival for the two groups. Overall survival was significantly better in patients who received photodynamic therapy than those who did not [HR=0.49, 95% confidence interval (CI), 0.33∼0.73, P=0.0005]. Among the 8 trials (642 subjects), 5 assessed the changes of serum bilirubin levels, and/or Karnofsky performance status, as other indications for improvement. In all, the incidence for phototoxic reaction is 11.11%. The incidence for other events in photodynamic therapy and the stent-only group was 13.64% and 12.79%, respectively.

CONCLUSION

The palliative treatment of cholangiocarcinoma, with photodynamic therapy, is associated with an increased survival benefit, an improved biliary drainage, and a better quality of life. However, the quality of this evidence is low.

Temoporfin improves efficacy of photodynamic therapy in advanced biliary tract carcinoma: A multicenter prospective phase II study

Photodynamic therapy using porfimer (P-PDT) improves palliation and survival in nonresectable hilar bile duct cancer. Tumoricidal penetration depth of temoporfin-PDT (T-PDT) is twice that of P-PDT. In a single-arm phase II study we investigated the safety, efficacy, survival time, and adverse events of T-PDT compared with previous data on P-PDT. Twenty-nine patients (median 71 [range 47-88] years) with nonresectable hilar bile duct cancer were treated with T-PDT (median 1 [range 1-4] sessions) plus stenting and followed up every 3 months. The PDT was well tolerated. In patients with occluded segments at baseline (n=28) a reopening of a median of 3 (range 1-7) segments could be achieved: n=16 local response and n=11 stable local disease, one progressive disease. Cholestasis and performance significantly improved when impaired at baseline. Time to local tumor progression was a median of 6.5 (2.7-41.0) months. Overall survival time was a median of 15.4 (range 4.4-62.4) months. Patients died from tumor progression (55%), cholangitis (18%), pneumonia (7%), hemobilia (7%), esophagus variceal hemorrhage (3%), and vascular diseases (10%). Adverse events were cholangitis (n=4), liver abscess (n=2), cholecystitis (n=2), phototoxic skin (n=5), and injection site reactions (n=7). Compared to previous P-PDT, T-PDT shows prolonged time to local tumor progression (median 6.5 versus 4.3 months, P<0.01), fewer PDT treatments needed (median 1 versus 3, P<0.01), a higher 6-month survival rate (83% versus 70%, P<0.01), and a trend for longer overall median survival (15.4 versus 9.3 months, P=0.72) yet not significantly different. The risk of adverse events is not increased except for (avoidable) subcutaneous phototoxicity at the injection site.

CONCLUSION

Temoporfin-PDT can safely be delivered to hilar bile duct cancer patients and results in prolonged patency of hilar bile ducts, a trend for longer survival time, and similar palliation as with P-PDT.

Is There Any Evidence for a Role of Local Treatment in Cholangiocarcinoma?

Background

Most cholangiocarcinomas (CCA) are locally advanced and unresectable at the time of diagnosis. Currently, chemotherapy combining gemcitabine with a platinum agent is the recommended first-line treatment regimen for advanced biliary tract cancer. However, median overall survival is only approximately 1 year. As the hepatic tumor burden is the limiting factor for the prognosis of these patients, local tumor control is essential.

Methods

We present and discuss the current evidence for such therapy options for patients with CCA.

Results

Local and locoregional therapies have been shown to be well tolerated and can contribute to tumor control in the context of a comprehensive oncologic treatment strategy, and may prolong survival of patients with advanced CCA. Unfortunately, only few high-quality clinical trials are available.

Conclusion

Randomized prospective clinical trials enrolling larger numbers of patients need to be carried out to elucidate the precise value of these treatments alone as well as in combination with systemic chemotherapy.

Dual roles of nitric oxide in the regulation of tumor cell response and resistance to photodynamic therapy

Photodynamic therapy (PDT) against cancer has gained attention due to the successful outcome in some cancers, particularly those on the skin. However, there have been limitations to PDT applications in deep cancers and, occasionally, PDT treatment resulted in tumor recurrence. A better understanding of the underlying molecular mechanisms of PDT-induced cytotoxicity and cytoprotection should facilitate the development of better approaches to inhibit the cytoprotective effects and also augment PDT-mediated cytotoxicity. PDT treatment results in the induction of iNOS/NO in both the tumor and the microenvironment. The role of NO in cytotoxicity and cytoprotection was examined. The findings revealed that NO mediates its effects by interfering with a dysregulated pro-survival/anti-apoptotic NF-κB/Snail/YY1/RKIP loop which is often expressed in cancer cells. The cytoprotective effect of PDT-induced NO was the result of low levels of NO that activates the pro-survival/anti-apoptotic NF-κB, Snail, and YY1 and inhibits the anti-survival/pro-apoptotic and metastasis suppressor RKIP. In contrast, PDT-induced high levels of NO result in the inhibition of NF-kB, Snail, and YY1 and the induction of RKIP, all of which result in significant anti-tumor cytotoxicity. The direct role of PDT-induced NO effects was corroborated by the use of the NO inhibitor, l-NAME, which reversed the PDT-mediated cytotoxic and cytoprotective effects. In addition, the combination of the NO donor, DETANONOate, and PDT potentiated the PDT-mediated cytotoxic effects. These findings revealed a new mechanism of PDT-induced NO effects and suggested the potential therapeutic application of the combination of NO donors/iNOS inducers and PDT in the treatment of various cancers. In addition, the study suggested that the combination of PDT with subtoxic cytotoxic drugs will result in significant synergy since NO has been shown to be a significant chemo-immunosensitizing agent to apoptosis.

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PDT-mediated cytotoxic and cytoprotective effects depend also by the induction of NO from tumor.

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The PDT-induced NO modulates the dysregulated NF-kB/Snail/RKIP loop.

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The direct role of NO induction by PDT was corroborated by the use of the NO inhibitor, l-NAME.

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The combination of an NO donor and PDT resulted in a increased cytotoxic effect, in vitro and in vivo.

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Novel potential therapeutic applications are proposed for the use of PDT combined with NO donors.

Advances in endoscopic retrograde cholangiopancreatography for the treatment of cholangiocarcinoma

Cholangiocarcinoma (CCA) is a malignancy of the bile ducts that carries high morbidity and mortality. Patients with CCA typically present with obstructive jaundice, and associated complications of CCA include cholangitis and biliary sepsis. Endoscopic retrograde cholangiopancreatography (ERCP) is a valuable treatment modality for patients with CCA, as it enables internal drainage of blocked bile ducts and hepatic segments by using plastic or metal stents. While there remains debate as to if bilateral (or multi-segmental) hepatic drainage is required and/or superior to unilateral drainage, the underlying tenant of draining any persistently opacified bile ducts is paramount to good ERCP practice and good clinical outcomes. Endoscopic therapy for malignant biliary strictures from CCA has advanced to include ablative therapies via ERCP-directed photodynamic therapy (PDT) or radiofrequency ablation (RFA). While ERCP techniques cannot cure CCA, advancements in the field of ERCP have enabled us to improve upon the quality of life of patients with inoperable and incurable disease. ERCP-directed PDT has been used in lieu of brachytherapy to provide neoadjuvant local tumor control in patients with CCA who are awaiting liver transplantation. Lastly, mounting evidence suggests that palliative ERCP-directed PDT, and probably ERCP-directed RFA as well, offer a survival advantage to patients with this difficult-to-treat malignancy.

Photodynamic Therapy using Talaporfin Sodium for the Recurrence of Cholangiocarcinoma after Surgical Resection

We herein report the case of a 72-year-old man who underwent photodynamic therapy (PDT) with talaporfin sodium for recurrent cholangiocarcinoma after surgical resection. Endoscopic retrograde cholangiography (ERC) showed severe stenosis with an irregular surface measuring approximately 1 cm in length from the anastomotic site, and a recurrent nodular lesion was observed at the anastomotic site of the right anterior intrahepatic bile duct on gastrointestinal endoscopy. ERC after PDT revealed a dramatic improvement in the bile duct stenosis, and the nodular lesion had disappeared. No adverse events from the PDT were detected. PDT using talaporfin sodium may be a safe alternative treatment for cholangiocarcinoma.

In vivo studies of nanostructure-based photosensitizers for photodynamic cancer therapy

Animal models, particularly rodents, are major translational models for evaluating novel anticancer therapeutics. In this review, different types of nanostructure-based photosensitizers that have advanced into the in vivo evaluation stage for the photodynamic therapy (PDT) of cancer are described. This article focuses on the in vivo efficacies of the nanostructures as delivery agents and as energy transducers for photosensitizers in animal models. These materials are useful in overcoming solubility issues, lack of tumor specificity, and access to tumors deep in healthy tissue. At the end of this article, the opportunities made possible by these multiplexed nanostructure-based systems are summarized, as well as the considerable challenges associated with obtaining regulatory approval for such materials. The following questions are also addressed: (1) Is there a pressing demand for more nanoparticle materials? (2) What is the prognosis for regulatory approval of nanoparticles to be used in the clinic?

MicroRNAs associated with the efficacy of photodynamic therapy in biliary tract cancer cell lines

Photodynamic therapy (PDT) is a palliative treatment option for unresectable hilar biliary tract cancer (BTC) showing a considerable benefit for survival and quality of life with few side effects. Currently, factors determining the cellular response of BTC cells towards PDT are unknown. Due to their multifaceted nature, microRNAs (miRs) are a promising analyte to investigate the cellular mechanisms following PDT. For two photosensitizers, Photofrin® and Foscan®, the phototoxicity was investigated in eight BTC cell lines. Each cell line (untreated) was profiled for expression of n=754 miRs using TaqMan® Array Human MicroRNA Cards. Statistical analysis and bioinformatic tools were used to identify miRs associated with PDT efficiency and their putative targets, respectively. Twenty miRs correlated significantly with either high or low PDT efficiency. PDT was particularly effective in cells with high levels of clustered miRs 25-93*-106b and (in case of miR-106b) a phenotype characterized by high expression of the mesenchymal marker vimentin and high proliferation (cyclinD1 and Ki67 expression). Insensitivity towards PDT was associated with high miR-200 family expression and (for miR-cluster 200a/b-429) expression of differentiation markers Ck19 and Ck8/18. Predicted and validated downstream targets indicate plausible involvement of miRs 20a*, 25, 93*, 130a, 141, 200a, 200c and 203 in response mechanisms to PDT, suggesting that targeting these miRs could improve susceptibility to PDT in insensitive cell lines. Taken together, the miRNome pattern may provide a novel tool for predicting the efficiency of PDT and-following appropriate functional verification-may subsequently allow for optimization of the PDT protocol.

ERCP-directed radiofrequency ablation and photodynamic therapy are associated with comparable survival in the treatment of unresectable cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is a malignancy with a poor 5-year survival rate (5%-10%). ERCP-directed radiofrequency ablation (RFA) or photodynamic therapy (PDT) can be performed as palliative therapy for unresectable CCA. ERCP with PDT is associated with improved survival compared with stent placement alone. However, ERCP-directed RFA has not been directly compared with PDT in patients with CCA.

OBJECTIVE

To compare overall survival in patients with unresectable CCA who underwent palliative ERCP-directed RFA versus PDT.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care academic medical center.

PATIENTS

Forty-eight patients with unresectable CCA who underwent ERCP-directed ablative therapy for palliation of unresectable CCA.

INTERVENTIONS

ERCP-directed RFA or PDT.

MAIN OUTCOME MEASUREMENTS

Overall survival by Kaplan-Meier analysis after initial treatment with either RFA or PDT.

RESULTS

Patients who underwent RFA (n = 16) demonstrated an overall survival similar to that of those who underwent PDT (n = 32), with a median survival of 9.6 versus 7.5 months, respectively (P = .799). Patient age (P = .45), sex (P = .52), and lead time (P = .59) from presentation to initial RFA or PDT had no significant association with survival. The presence of distant metastasis was inversely associated with survival (hazard ratio 3.55; 95% confidence interval, 1.29-9.77; P = .014). Patients who underwent RFA (compared with PDT) had a lower mean number of plastic stents placed per month (0.45 vs 1.10, P = .001) but also had more episodes of stent occlusion (0.06 vs 0.02, P = .008) and cholangitis (0.13 vs 0.05, P = .008) per month.

LIMITATIONS

Retrospective, single-center design.

CONCLUSIONS

Survival after ERCP-directed RFA and PDT was not statistically different in patients with unresectable CCA. A randomized, controlled trial is warranted to validate these preliminary results.

Endoscopic treatment options for cholangiocarcinoma

Cholangiocarcinomas are often locally advanced or have metastasized, and at the time of diagnosis individuals often have a poor prognosis. Endoscopic treatment options traditionally include biliary decompression via stenting to allow for systemic chemotherapy and radiotherapy, with self-expanding metal biliary stents being preferred. Recent developments in locoregional therapy delivered endoscopically, such as photodynamic therapy and radiofrequency abalation, have shown promising results in improving patient survival.

Endoscopic treatment options for cholangiocarcinomas

Cholangiocellular carcinoma (CCC) is a very aggressive tumor, which remains highly resistant to current chemoradiation therapies. Death is usually caused by the tumor burden. However, biliary obstruction, which leads to cholangitis and liver failure, is also a cause of death. Therefore, relief of biliary obstruction is one of the key palliative treatment options for patients with hilar or distal CCC. Radiologic or endoscopic insertions of stents (plastic or self-expanding metal) are definite biliary drainage options. Whereas stents alone can help achieve relief of bile duct obstruction, endoscopic ablative interventions with photodynamic therapy or radiofrequency ablation are also useful in destroying intraluminal tumor. Destroying the tumor leads to an increase in the luminal diameter of the obstructed bile duct, allowing for placement of more or larger diameter stents, and thus improving bile flow. Besides decreasing morbidity associated with obstruction, ablative therapies such as photodynamic therapy have also been associated with improved survival in a sub-group of patients with CCC and should therefore be incorporated into the treatment algorithm of any center treating patients with CCC.

Photodynamic therapy in unresectable cholangiocarcinoma: not for the uncommitted

Background/Aims

Photodynamic therapy (PDT) in unresectable cholangiocarcinoma has been associated with improved survival. We report a single tertiary care center experience over the past 6 years.

Methods

Fifty-five patients with unresectable cholangiocarcinoma received PDT between 2004 and 2010. Plastic stents were placed after PDT to prevent cholangitis.

Results

Twenty-seven patients (49%) showed Bismuth type IV, 22 (41%) showed Bismuth type III, and six (10%) showed Bismuth type I and II. Twenty patients (37%) received chemotherapy and radiation therapy, five (9%) received chemotherapy only; and one (2%) received radiation therapy only. Mean number of PDT sessions was 1.9±1.5 sessions (range, 1 to 9). Mean survival duration was 293±266 days (median, 190; range, 25 to 1,332). PDT related complications included three (5%) facial burn, three (5%) photosensitivity, and two (3%) rash. Kaplan-Meier analysis comparing the survival means of patients who received PDT and chemotherapy/radiation therapy (median survival 257 days; 95% confidence interval [CI], 166 to 528) versus who received PDT only (median survival 183 days; 95% CI, 129 to 224) showed no significant difference (log-rank p=0.20).

Conclusions

PDT has a measurable impact on survival in unresectable cholangiocarcinoma but requires aggressive stenting posttherapy.

Endoscopic management of malignant bile duct strictures

Malignant biliary obstruction can arise from intrahepatic, extrahepatic, and hilar locations from either primary or metastatic disease. Biliary-enteric surgical bypass has been surpassed in the last 20 years by endoscopic balloon dilation and stenting. The goal of stenting for biliary decompression is to palliate obstructive symptoms; it has not been shown that survival is affected by stenting alone. Novel endoscopic therapies, including photodynamic therapy and radiofrequency ablation, have been evaluated and show promise. Both therapies seem to be safe and effective in the treatment of malignant bile duct strictures but are in need of prospective studies of longer duration.

Photodynamic therapy prolongs metal stent patency in patients with unresectable hilar cholangiocarcinoma

AIM: To evaluate the effect of photodynamic therapy (PDT) on metal stent patency in patients with unresectable hilar cholangiocarcinoma (CC).

METHODS: This was a retrospective analysis of patients with hilar CC referred to our institution from December, 1999 to January, 2011. Out of 232 patients, thirty-three patients with unresectable hilar CC were treated. Eighteen patients in the PDT group were treated with uncovered metal stents after one session of PDT. Fifteen patients in the control group were treated with metal stents alone. Porfimer sodium (2 mg/kg) was administered intravenously to PDT patients. Forty-eight hours later, PDT was administered using a diffusing fiber that was advanced across the tumor by either endoscopic retrograde cholangiopancreatography or percutaneous cholangiography. After performance of PDT, uncovered metal stents were inserted to ensure adequate decompression and bile drainage. Patient survival rates and cumulative stent patency were calculated using Kaplan-Meier analysis with the log-rank test.

RESULTS: The PDT and control patients were comparable with respect to age, gender, health status, pre-treatment bilirubin, and hilar CC stage. When compared to control, the PDT group was associated with significantly prolonged stent patency (median 244 ± 66 and 177 ± 45 d, respectively, P = 0.002) and longer patient survival (median 356 ± 213 and 230 ± 73 d, respectively, P = 0.006). Early complication rates were similar between the groups (PDT group 17%, control group 13%) and all patients were treated conservatively. Stent malfunctions occurred in 14 PDT patients (78%) and 12 control patients (80%). Of these 26 patients, twenty-two were treated endoscopically and four were treated with external drainage.

CONCLUSION: Metal stenting after one session of PDT may be safe with acceptable complication rates. The PDT group was associated with a significantly longer stent patency than the control group in patients with unresectable hilar CC.

Vehiculization determines the endocytic internalization mechanism of Zn(II)-phthalocyanine

It is generally accepted that compounds of nanomolecular size penetrate into cells by different endocytic processes. The vehiculization strategy of a compound is a factor that could determine its uptake mechanism. Understanding the influence of the vehicle in the precise mechanism of drug penetration into cells makes possible to improve or modify the therapeutic effects. In this study, using human A-549 cells, we have characterized the possible internalization mechanism of the photosensitizer Zn(II)-phthalocyanine (ZnPc), either dissolved in dimethylformamide (ZnPc-DMF) or included in liposomes of dipalmitoyl-phosphatidyl-choline. Specific inhibitors involved in the main endocytic pathways were used. Co-incubation of cells with ZnPc-liposomes and dynasore (dinamin-mediated endocytosis inhibitor) resulted in a significant decrease of photodamage, whereas other inhibitors did not alter the photodynamic effect of ZnPc. On the contrary, cells treated with ZnPc-DMF in the presence of dynasore, genistein (caveolin-mediated endocytosis inhibitor) or cytochalasin D (macropinocytosis and caveolin-mediated endocytosis inhibitor) showed a significant decrease in ZnPc uptake and photodynamic damage. These results suggest that ZnPc-DMF penetrates into cells mainly by caveolin-mediated endocytosis, whereas ZnPc-liposomes are internalized into cells preferentially by clathrin-mediated endocytosis. We conclude that using different drug vehiculization systems, it is possible to modify the internalization mechanism of a therapeutic compound, which could be of great interest in clinical research.

5-aminolevulinic acid-incorporated poly(vinyl alcohol) nanofiber-coated metal stent for application in photodynamic therapy

Background

The study investigated the use of combined photodynamic therapy (PDT) and stent placement for the treatment of cholangiocarcinoma (CC). For this purpose, 5-aminolevulinic acid (ALA) was incorporated into poly(vinyl alcohol) (PVA) nanofiber, and coated onto metal stents. Their efficacy was assessed in PDT towards HuCC-T1 CC cells.

Methods

Fabrication of ALA-PVA nanofiber, and simultaneous coating onto metal stents, was performed through electrospinning. The dark-toxicity, generation of protoporphyrin IX (PpIX), and PDT effect of ALA and ALA-PVA nanofiber were studied in vitro, using HuCC-T1 CC cells.

Results

The ALA-PVA nanofibers were coated onto metal stents less than 1000 nm in diameter. ALA-only displayed marginal cytotoxicity; ALA-PVA nanofiber showed less cytotoxicity. PpIX generation was not sigficantly different between ALA and ALA-PVA nanofiber treatments. PVA itself did not generate PpIX in tumor cells. ALA and ALA-PVA nanofiber displayed a similar PDT effect on tumor cells. Cell viability was decreased, dose-dependently, until ALA concentration reached 100 μg/mL. Necrosis and apoptosis of tumor cells occurred similarly for ALA and ALA- PVA nanofiber treatments.

Conclusion

The ALA-PVA nanofiber-coated stent is a promising candidate for therapeutic use with cholangiocarcinoma.