Photodynamic therapy for pancreatic and biliary tract carcinoma

ACG Clinical Guideline: Diagnosis and Management of Biliary Strictures

A biliary stricture is an abnormal narrowing in the ductal drainage system of the liver that can result in clinically and physiologically relevant obstruction to the flow of bile. The most common and ominous etiology is malignancy, underscoring the importance of a high index of suspicion in the evaluation of this condition. The goals of care in patients with a biliary stricture are confirming or excluding malignancy (diagnosis) and reestablishing flow of bile to the duodenum (drainage); the approach to diagnosis and drainage varies according to anatomic location (extrahepatic vs perihilar). For extrahepatic strictures, endoscopic ultrasound-guided tissue acquisition is highly accurate and has become the diagnostic mainstay. In contrast, the diagnosis of perihilar strictures remains a challenge. Similarly, the drainage of extrahepatic strictures tends to be more straightforward and safer and less controversial than that of perihilar strictures. Recent evidence has provided some clarity in multiple important areas pertaining to biliary strictures, whereas several remaining controversies require additional research. The goal of this guideline is to provide practicing clinicians with the most evidence-based guidance on the approach to patients with extrahepatic and perihilar strictures, focusing on diagnosis and drainage.

Porphylipoprotein Accumulation and Porphylipoprotein Photodynamic Therapy Effects Involving Cancer Cell-Specific Cytotoxicity

In photodynamic therapy (PDT) for neoplasms, photosensitizers selectively accumulate in cancer tissue. Upon excitation with light of an optimal wavelength, the photosensitizer and surrounding molecules generate reactive oxygen species, resulting in cancer cell-specific cytotoxicity. Porphylipoprotein (PLP) has a porphyrin-based nanostructure. The porphyrin moiety of PLP is quenched because of its structure. When PLP is disrupted, the stacked porphyrins are separated into single molecules and act as photosensitizers. Unless PLP is disrupted, there is no photosensitive disorder in normal tissues. PLP can attenuate the photosensitive disorder compared with other photosensitizers and is ideal for use as a photosensitizer. However, the efficacy of PLP has not yet been evaluated. In this study, the mechanism of cancer cell-specific accumulation of PLP and its cytotoxic effect on cholangiocarcinoma cells were evaluated. The effects were investigated on normal and cancer-like mutant cells. The cytotoxicity effect of PLP PDT in cancer cells was significantly stronger than in normal cells. In addition, reactive oxygen species regulated intracellular PLP accumulation. The cytotoxic effects were also investigated using a cholangiocarcinoma cell line. The cytotoxicity of PLP PDT was significantly higher than that of laserphyrin-based PDT, a conventional type of PDT. PLP PDT could also inhibit tumor growth in vivo.

Photodestruction of Stromal Fibroblasts Enhances Tumor Response to PDT in 3D Pancreatic Cancer Coculture Models

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of human cancers. The dismal response of PDAC to virtually all therapeutics is associated, in part, with a characteristically dense fibrotic stroma. This stroma not only acts as a barrier to drug perfusion, but also promotes tumor survival through paracrine crosstalk and biophysical interactions. Photodynamic therapy (PDT) is being explored for PDAC treatment, though the impact of tumor-promoting stromal crosstalk on PDT response in PDAC is not well-characterized. The current study assesses the effect of tumor-stroma interactions on response to PDT or chemotherapy in heterocellular 3D cocultures using PDAC cells and two different fibroblastic cell types (pancreatic stellate cells, PSCs, and a normal human fibroblast cell line, MRC5) embedded in extracellular matrix (ECM). While stromal fibroblasts promote resistance to chemotherapy as expected, PDAC 3D nodules in coculture with fibroblasts exhibit increased response to PDT relative to homotypic cultures. These results point to the potential for PDT to overcome tumor-promoting stromal interactions associated with poor therapeutic response in PDAC.

Role of Ultrasound and Photoacoustic Imaging in Photodynamic Therapy for Cancer

Photodynamic therapy (PDT) is a phototoxic treatment with high spatial and temporal control and has shown tremendous promise in the management of cancer due to its high efficacy and minimal side effects. PDT efficacy is dictated by a complex relationship between dosimetry parameters such as the concentration of the photosensitizer at the tumor site, its spatial localization (intracellular or extracellular), light dose and distribution, oxygen distribution and concentration, and the heterogeneity of the inter- and intratumoral microenvironment. Studying and characterizing these parameters, along with monitoring tumor heterogeneity pre- and post-PDT, provides essential data for predicting therapeutic response and the design of subsequent therapies. In this review, we elucidate the role of ultrasound (US) and photoacoustic imaging in improving PDT-mediated outcomes in cancer-from tracking photosensitizer uptake and vascular destruction, to measuring oxygenation dynamics and the overall evaluation of tumor responses. We also present recent advances in multifunctional theranostic nanomaterials that can improve either US or photoacoustic imaging contrast, as well as deliver photosensitizers specifically to tumors. Given the wide availability, low-cost, portability and nonionizing nature of US and photoacoustic imaging, together with their capabilities of providing multiparametric morphological and functional information, these technologies are thusly inimitable when deployed in conjunction with PDT.

Photodynamic activity of new photosensitizers obtained from 5,10,15,20-tetrapentafluorophenylporphyrin

The commercially available tetrapentafluorophenylporphyrin has been used as parent compounds for the synthesis of six new tetraarylporphyrins. These new porphyrins were obtained following aromatic nucleophilic substitution of the para-position fluorine atoms by means of molecules bearing an oxygen or sulphur anion, providing either tri- or tetra-substituted derivatives which were isolated as pure compounds after a single step of column chromatography purification. These new porphyrins, first analyzed to determine the photobleaching stability and the octanol/water repartition values, were studied as photosensitizers against the HCT116 cancer cell line with irradiation by a blue LED device. The intrinsic toxicity of these compounds was negligible, whereas the photodynamic efficacy was found to be directly related to the cellular uptake of the photosensitizer that was correlated with the hydrophilicity of the substituent. In fact, the PSs lacking of any polar groups were found to be poorly efficient while the photosensitizer bearing four hydroxyl groups showed the greatest photodynamic activity, thus confirming the importance of the presence of polar appendixes to properly interact with the cells, thus exerting the desired photo-killing effect.

Simultaneous delivery of cytotoxic and biologic therapeutics using nanophotoactivatable liposomes enhances treatment efficacy in a mouse model of pancreatic cancer

A lack of intracellular delivery systems has limited the use of biologics such as monoclonal antibodies (mAb) that abrogate molecular signaling pathways activated to promote escape from cancer treatment. We hypothesized that intracellular co-delivery of the photocytotoxic chromophore benzoporphyrin derivative monoacid A (BPD) and the anti-VEGF mAb bevacizumab in a nanophotoactivatable liposome (nanoPAL) might enhance the efficacy of photodynamic therapy (PDT) combined with suppression of VEGF-mediated signaling pathways. As a proof-of-concept we found that nanoPAL-PDT induced enhanced extra- and intracellular bevacizumab delivery and enhanced acute cytotoxicity in vitro. In an in vivo subcutaneous mouse model of pancreatic ductal adenocarcinoma, nanoPAL-PDT achieved significantly enhanced tumor reduction. We attribute this to the optimal incorporation of insoluble BPD into the lipid bilayer, enhancing photocytotoxicity, and the simultaneous spatiotemporal delivery of bevacizumab, ensuring efficient neutralization of the rapid but transient burst of VEGF following PDT. From the Clinical Editor: Most patients with pancreatic ductal adenocarcinoma (PDAC) by the time present the disease it is very advanced, which unavoidably translates to poor survival. For these patients, use of traditional chemotherapy often becomes ineffective due to tumor resistance to drugs. Photodynamic therapy (PDT) can be an effective modality against chemo-resistant cancers. In this article, the authors investigated the co-delivery of a photocytotoxic agent and anti-VEGF mAb using liposomes. This combination was shown to results in enhanced tumor killing. This method should be applicable to other combination of treatments.

PDT dose parameters impact tumoricidal durability and cell death pathways in a 3D ovarian cancer model

The successful implementation of photodynamic therapy (PDT)-based regimens depends on an improved understanding of the dosimetric and biological factors that govern therapeutic variability. Here, the kinetics of tumor destruction and regrowth are characterized by systematically varying benzoporphyrin derivative (BPD)-light combinations to achieve fixed PDT doses (M × J cm(-2)). Three endpoints were used to evaluate treatment response: (1) Viability evaluated every 24 h for 5 days post-PDT; (2) Photobleaching assessed immediately post-PDT; and (3) Caspase-3 activation determined 24 h post-PDT. The specific BPD-light parameters used to construct a given PDT dose significantly impact not only acute cytotoxic efficacy, but also treatment durability. For each dose, PDT with 0.25 μM BPD produces the most significant and sustained reduction in normalized viability compared to 1 and 10 μM BPD. Percent photobleaching correlates with normalized viability for a range of PDT doses achieved within BPD concentrations. To produce a cytotoxic response with 10 μM BPD that is comparable to 0.25 and 1 μM BPD a reduction in irradiance from 150 to 0.5 mW cm(-2) is required. Activated caspase-3 does not correlate with normalized viability. The parameter-dependent durability of outcomes within fixed PDT doses provides opportunities for treatment customization and improved therapeutic planning.

Effect of Photofrin-mediated photocytotoxicity on a panel of human pancreatic cancer cells

BACKGROUND AND OBJECTIVE

Pancreatic cancer is a leading cause of cancer-related deaths in men and women. Early clinical studies suggest that photodynamic therapy (PDT) might be a useful modality in the management of this deadly disease. In this study, the photocytotoxicity of Photofrin-mediated PDT on different human pancreatic cancer cells (BxPc-3, HPAF-II, Mia PaCa-2, MPanc-96, PANC-1 and PL-45) was examined.

MATERIALS AND METHODS

After co-incubating cancer cells with Photofrin (0-10 μg/ml) for 4h, the cells were irradiated with 0-6J/cm(2) of 630 nm light. The effect of Photofrin PDT on the survival of cells were examined using tetrazolium-based colorimetric assay and clonogenic assay. PDT-induced apoptosis was analyzed by flow cytometry. Expressions of apoptosis-related proteins were determined by western blot analysis.

RESULTS

Photofrin PDT strongly inhibited the survival of pancreatic cancer cells. A small portion of cells (<15%) underwent apoptosis 24h after PDT at LD50. Cleavage of caspase-3, caspase-8, caspase-9 and PARP after PDT were also confirmed. BxPc-3, Mia PaCa-2, MPanc-96, and PANC-1 cells were more sensitive and HPAF-II and PL-45 cells less sensitive.

CONCLUSION

Photofrin PDT can induce apoptosis and inhibit survival of human pancreatic cancer cells.

Verteporfin-based photodynamic therapy overcomes gemcitabine insensitivity in a panel of pancreatic cancer cell lines

BACKGROUND AND OBJECTIVE

Pancreatic cancer is notoriously difficult to treat and resistant to virtually all therapeutics including gemcitabine, the standard front line agent for palliative chemotherapy. Early clinical studies point to a potential role for photodynamic therapy (PDT) in the management of this deadly disease. Here we examine PDT with verteporfin for treatment of cells that are nonresponsive to gemcitabine and identify intracellular and extracellular factors that govern sensitivity to each modality.

STUDY DESIGN

Using MTS we assess cytotoxicity of verteporfin-PDT in gemcitabine-treated nonresponsive populations from a panel of five pancreatic cancer cell lines representing a range of tumor histopathology and origin. We conduct Western blots for pro-/anti-apoptotic proteins bax and Bcl-XL to identify factors relevant to PDT and gemcitabine sensitivity. To examine the role of extracellular matrix influences we compare response to each modality in traditional cell culture conditions and cells grown on a laminin-rich basement membrane.

RESULTS

All cell lines have gemcitabine nonresponsive populations (17-33%) at doses up to 1 mM while moderate total verteporfin PDT doses (1-6 µM J/cm2) produce nearly complete killing. Our data shows that cells that are nonresponsive to sustained gemcitabine incubation are sensitive to verteporfin PDT indicating that the latter is agnostic to gemcitabine sensitivity. Verteporfin-based PDT decreases Bcl-XL and increases the bax/Bcl-XL ratio toward a pro-apoptotic balance. Insensitivity to gemcitabine is increased in cells that are adherent to basement membrane relative to traditional tissue culture conditions.

CONCLUSIONS

Collectively these results indicate the ability of verteporfin-based PDT to bypass intracellular and extracellular cues leading to gemcitabine resistance and point to the emerging role of this therapy for treatment of pancreatic cancer.

Advances in photodynamic therapy for the treatment of hilar biliary tract cancer

The prognosis of patients with nonresectable hilar biliary tract cancer (hBTC) is poor. Responsiveness to chemotherapy or radiochemotherapy is moderate at best, and patients are at a high risk of dying early from complications of local tumor infiltration (e.g., cholestasis, septic cholangitis, empyema or liver failure) rather than systemic disease. Therefore, palliative local therapy for the prevention of tumor complications plays a central role and still yields the longest survival times. Photodynamic therapy (PDT) is a local-ablative, tumor tissue-specific treatment currently representing the standard of care for nonresectable hBTC. Throughout the literature, PDT plus biliary drainage achieves median survival times in the range of 9-21 months (average 14-16 months), compared with approximately 6 months for drainage only. This article summarizes the recent advances in preclinical and clinical experience of PDT for hBTC, including experimental in vitro and in vivo studies, clinical studies and an overview of the ongoing clinical trials.

R0 but not R1/R2 resection is associated with better survival than palliative photodynamic therapy in biliary tract cancer

BACKGROUND

There is a need for better management strategies to improve the survival and quality of life in patients with biliary tract cancer (BTC).

AIM

To assess prognostic factors for survival in a large, non-selective cohort of patients with BTC.

METHOD

We compared outcomes in 321 patients with a final diagnosis of BTC (cholangiocarcinoma n = 237, gallbladder cancer n = 84) seen in a tertiary referral cancer centre between 1998 and 2007. Survival according to disease stage and treatment category was compared using log-rank testing. Cox's regression analysis was used to determine independent prognostic factors.

RESULTS

Eighty-nine (28%) patients underwent a surgical intervention with curative intent, of whom 38% had R0 resections. Among the 321 patients, 34% were given chemo- and/or radiotherapy, 14% were palliated with photodynamic therapy (PDT) and 37% with biliary drainage procedures alone. The overall median survival was 9 months (3-year survival, 14%). R0-resective surgery conferred the most favourable outcome (3-year survival, 57%). Although patients palliated with PDT had more advanced clinical T-stages, their survival was similar to those treated with attempted curative surgery but who had positive resection margins. On multivariable analysis, treatment modality, serum carbohydrate-associated antigen 19-9, distant metastases and vascular involvement were independent prognostic indicators of survival.

CONCLUSION

In this large UK series of BTC, palliative PDT resulted in survival similar to those with curatively intended R1/R2 resections. Surgery conferred a survival advantage only in patients with R0 resection margins, emphasising the need for accurate pre-operative staging.

Photodynamic therapy: Palliation and endoscopic technique in cholangiocarcinoma

Cholangiocarcinoma is the primary malignancy arising from the biliary epithelium. The disease is marked by jaundice, cholestasis, and cholangitis. Over 50 percent of patients present with advanced stage disease, precluding curative surgical resection as an option of treatment. Prognosis is poor, and survival has been limited even after biliary decompression. Palliative management has become the standard of care for unresectable disease and has evolved to include an endoscopic approach. Photodynamic therapy (PDT) consists of administration of a photosensitizer followed by local irradiation with laser therapy. Several studies conducted in Europe and the United States have shown a marked improvement in the symptoms of cholestasis, survival, and quality of life. This article summarizes the published experience regarding PDT for cholangiocarcinoma and the steps required to administer this therapy safely.

Photodynamic therapy for cholangiocarcinoma

Cholangiocarcinoma is the primary malignancy arising from the biliary epithelium, and it presents as jaundice, cholestasis, and cholangitis. Over 50 percent of patients present with advanced-stage disease, and the prognosis is poor with the survival measured in months even after biliary decompression. Palliative management has become the standard of care for unresectable disease, and this involves an endoscopic approach. Photodynamic therapy (PDT) involves the administration of a photosensitizer followed by local irradiation with laser therapy. The use of PDT for palliation of bile-duct tumors has produced promising results. Several studies conducted in Europe and the United States have shown that PDT produces a marked improvement in the symptoms of cholestasis, survival, and quality of life. This chapter summarizes the principle of PDT, the technique employed, and the published experience regarding PDT for cholangiocarcinoma.

The role of porphyrin chemistry in tumor imaging and photodynamic therapy

In recent years several review articles and books have been published on the use of porphyrin-based compounds in photodynamic therapy (PDT). This critical review is focused on (i) the basic concept of PDT, (ii) advantages of long-wavelength absorbing photosensitizers (PS), (iii) a brief discussion on recent advances in developing PDT agents, and (iv) the various synthetic strategies designed at the Roswell Park Cancer Institute, Buffalo, for developing highly effective long-wavelength PDT agents and their utility in constructing the conjugates with tumor-imaging and therapeutic potential (Theranostics). The clinical status of certain selected PDT agents is also summarized (205 references).

Photodynamic therapy for non-resectable perihilar cholangiocarcinoma

Photodynamic therapy (PDT) has emerged as a useful tool for palliative treatment of the otherwise difficult to treat perihilar cholangiocarcinoma (CC). PDT is a minimally invasive and effective technique for local tumour ablation with rare and predictable side effects. A modest number of studies and randomised trials using porfimer (Photofrin) could demonstrate an improvement in quality of life and survival time. A novel approach to a priori non-resectable perihilar CC was proven in a pilot study using neoadjuvant porfimer-PDT for down-sizing of the tumour followed by R0 resection. These days, active phase II and phase III trials investigate if the tumouricidal activity can be increased using temoporfin (Foscan) as an alternative photosensitiser with higher penetration capability and whether porfimer-based PDT plus stenting is superior to biliary stenting alone in terms of overall survival, respectively. The local tumour ablation and correction of obstructive cholestasis with PDT will allow for novel multimodal strategies to treat cholangiocarcinoma.

Photodynamic therapy of malignant biliary strictures using meso-tetrahydroxyphenylchlorin

OBJECTIVES

The palliation of patients with malignant bile duct obstruction using metal or plastic biliary stents may be limited by stent occlusion. The aim of this study was to determine the safety and efficacy of endoscopically delivered meso-tetrahydroxyphenyl chlorin photodynamic therapy in the treatment of irresectable malignant biliary strictures and recurrent stent occlusion.

METHODS

Thirteen patients with malignant biliary obstruction owing to carcinoma of the biliary tract (n=9), pancreas (n=3) or stomach (n=1), were studied. All had been initially palliated with metal (n=10) or polyethylene (n=3) biliary stents, but presented with recurrent obstructive jaundice because of local tumour progression. Patients received meso-tetrahydroxyphenyl chlorin 0.15 mg/kg intravenously 72 h before endoluminal light activation with an endoscopically placed optical fibre, followed by polyethylene stent insertion.

RESULTS

Before photodynamic therapy, patients had a median of three (range 0-5) stent occlusions in the preceding 11 (2-22) months, with a median patency of plastic stents placed inside metal bile duct stents for recurrent stent occlusion of 3.5 (0.5-13) months. After photodynamic treatment, tumour necrosis and/or metal stent recanalization was seen in all patients, with a median of 0 (0-3) stent occlusions during 7 (1-43) months follow-up. The median patency of plastic stents placed inside metal stents after photodynamic therapy was 5 (1-43) months. The median survival after diagnosis and photodynamic therapy administration was 21 (10-56) and 8 (1-43) months, respectively. Photodynamic therapy was generally well tolerated but two patients developed cholangitis within the first week, complicated in one by a fatal liver abscess and two developed haemobilia within 4 weeks of treatment, one of whom died with a gall bladder empyema.

CONCLUSION

In patients with malignant biliary obstruction, endoscopically delivered meso-tetrahydroxyphenyl chlorin photodynamic therapy causes efficient tumour necrosis and recanalization of blocked metal stents, but there is a significant risk of complications.

Photodynamic therapy using verteporfin photosensitization in the pancreas and surrounding tissues in the Syrian golden hamster

BACKGROUND/AIM

Photodynamic therapy (PDT) is a potential treatment for locally advanced pancreatic cancer. We aimed to assess the safety of interstitial PDT using verteporfin (benzoporphyrin derivative monoacid A - a novel photosensitizer with a short drug-light interval and limited cutaneous photosensitivity) in the Syrian golden hamster, and compare it to meso-tetrahydroxyphenylchlorin (mTHPC) which we have previously evaluated in preclinical and clinical studies.

METHODS

Verteporfin (2 mg/kg) was administered at laparotomy by inferior vena caval injection (n = 57), with plasma levels quantified at 5, 15, 30, 60 and 240 min, and 24 h. 15 min after photosensitization, tissues (liver, pancreas, duodenum, colon, aorta) were illuminated with 690 nm red laser light (150 mW), at a range of light doses (1-100 J/cm(2)). The PDT effects on the targeted organ and adjacent structures were assessed at post-mortem on days 3 and 21, or at the time of death.

RESULTS

The elimination half-life of verteporfin was 4-5 h. Light doses of 10, 25 and 50 J/cm(2) were safe in the hamster pancreas, liver and colon, respectively, and produced coagulative necrotic lesions of 3 (range 3-4), 10 (9-10) and 7 (7-8) mm diameter. Collagen was resistant to damage and lesions healed mainly by regeneration of normal tissue. At higher light doses, necrosis extended to the edge of organs, sometimes causing sealed duodenal perforations as seen with mTHPC.

CONCLUSION

The safety profile of verteporfin is very similar to mTHPC, with the advantages of a shorter drug-light interval and drug elimination time. Phase I clinical studies using this photosensitizer in pancreatic cancer should be feasible.

Comparative characterization of the efficiency and cellular pharmacokinetics of Foscan- and Foslip-based photodynamic treatment in human biliary tract cancer cell lines

Due to the poor prognosis and limited management options for perihilar cholangiocarcinoma (CC) the development of alternatives for treatment is an important topic. Photodynamic therapy (PDT) with porfimer as palliative or neoadjuvant endoscopic treatment of non-resectable perihilar CC has improved quality of life and survival time, but cannot eradicate the primary tumors because of inadequate tumoricidal depth (4 mm only around the tumor stenoses). The use of meta-tetrahydroxyphenyl chlorin (mTHPC) and photoactivation at higher wavelengths (650-660 nm) provides high tumoricidal depth (10 mm) for PDT of pancreatic cancer and should yield similar tumoricidal depth in CC. This study investigates the photodynamic characteristics of mTHPC in solvent-based formulation (Foscan) and in liposomal (water soluble) formulation (Foslip) in an in vitro model system consisting of two biliary cancer cell lines (GBC, gall bladder cancer and BDC, bile duct cancer cells). Dark toxicity, photodynamic efficiency, time-dependent uptake and retention and intracellular localization of Foscan and Foslip were studied. The results prove mTHPC as a potent photosensitizing agent with high phototoxic potential in biliary cancer cells as a concentration of 600 ng ml(-1) and irradiation with 1.5 J cm(-2) (660 +/- 10 nm) is sufficient for about 90% cell killing. Addition of foetal bovine serum (FBS) to the incubation medium and analysis of the uptake and phototoxic properties reveals that both photosensitizer formulations bind to serum protein fractions, i.e. no difference between Foscan and Foslip can be found in the presence of FBS. Laser scanning fluorescence microscopy indicates a similar pattern of perinuclear localization of both sensitizers. This study demonstrates the potential of mTHPC for treatment of bile duct malignancies and provides evidence that Foslip is an equivalent water-soluble formulation of mTHPC that should ease intravenous application and thus clinical use of mTHPC.

New advances in the management of biliary tract cancer

Biliary tract cancers are uncommon malignancies arising from biliary epithelium intrahepatically (peripheral cholangiocarcinoma), in the extrahepatic bile duct, the gall bladder and the ampulla of Vater. Treatment has been challenging because of late presentation, complex surgery, complex biliary obstruction with jaundice and a paucity of high quality data on which to establish standard care. With improvements in imaging, biliary stenting, surgical management and the establishment of a national investigational programme we hope to define the modern management of biliary tract cancers and enable a platform for further research.

Phototoxicity of Hemoporfin to ovarian cancer

Hematoporphyrin monomethyl ether (Hemoporfin) is a novel porphyrin-related photosensitizer. Photocytotoxic effect of Hemoporfin to ovarian cancer is still unclear. We used human epithelial ovarian carcinoma cell line SKOV3 and its xenograft model in nude mice to investigate the Hemoporfin-based photodynamic therapy (PDT) for ovarian cancer. The growth rates of SKOV3 cells were determined by MTT assays. Flow cytometry combined with dual Annexin V/PI staining was used to identify the death mode of the cells following PDT. We demonstrated that Hemoprofin-based PDT induced significant cell death via direct necrosis induction, and the photocytotoxity to SKOV3 cells is dose related. With SKOV3 xenograft model in nude mouse, we further demonstrated that Hemoporfin-based PDT is effective for controlling the tumor growth. Our results suggest that Hemoporfin is a promising novel photosensitizer for the treatment of ovarian cancer and merit further evaluation in the clinical practice.

Uses of photodynamic therapy in premalignant and malignant lesions of the gastrointestinal tract beyond the esophagus

Much has recently been written regarding the use of photodynamic therapy for the treatment of esophageal carcinoma and dysplastic Barrett's esophagus. This review, however, describes the clinical experience using photodynamic therapy with various photosensitizer agents for the treatment of diseases in other areas of the gut, especially the pancreaticobiliary tract where European studies have established the role of porfimer sodium photodynamic therapy in the management of patients with cholangiocarcinoma.

A review of progress in clinical photodynamic therapy

Photodynamic therapy (PDT) has received increased attention since the regulatory approvals have been granted to several photosensitizing drugs and light applicators worldwide. Much progress has been seen in basic sciences and clinical photodynamics in recent years. This review will focus on new developments of clinical investigation and discuss the usefulness of various forms of PDT techniques for curative or palliative treatment of malignant and non-malignant diseases.