Photodynamic therapy in lung cancer. A review

Fluorescence probes for lung carcinoma diagnosis and clinical application

This review provides an overview of the most recent developments in fluorescence probe technology for the accurate detection and clinical therapy of lung carcinoma.

Targeted Photodynamic Therapy (PDT) of Lung Cancer with Biotinylated Silicon (IV) Phthalocyanine

BACKGROUND

Lung cancer is the leading cause of cancer-associated mortality in the world. Traditional cancer therapies prolong the life expectancy of patients but often suffer from adverse reactions. Photodynamic Therapy (PDT) has been recommended as a treatment option for lung cancer in several countries, due to its non-invasive procedures, high selectivity and weak side effects.

OBJECTIVE

We have designed and synthesized a biotin receptor-targeted silicon phthalocyanine (IV) (compound 1) which showed a good therapeutic effect on biotin receptor-positive tumors. Since the overexpression of Biotin Receptor (BR) is also present in human lung cancer cells (A549), we explored the therapeutic properties of compound 1 on A549 xenograft tumor models.

METHODS

The selectivity of compound 1 toward A549 cells was studied with a fluorescence microscope and IVIS Spectrum Imaging System. The cytotoxicity was measured using the MTT assay. In vivo anti-tumor activity was investigated on the nude mice bearing A549 xenografts.

RESULTS

In vitro assays proved that compound 1 could selectively accumulate in A549 cells via the BR-mediated internalization. In vivo imaging and distribution experiments showed that compound 1 could selectively accumulate in tumor tissues of tumor-bearing mice. After 16 days of the treatment, the volumes of tumor in the PDT group were obviously smaller than that in other groups.

CONCLUSION

This study demonstrates that compound 1 is a promising photosensitizer and has broad application prospects in clinical PDT of lung cancers.

Apoptotic mechanism activated by blue light and cisplatinum in cutaneous squamous cell carcinoma cells

New approaches are being studied for the treatment of skin cancer. It has been reported that light combined with cisplatinum may be effective against skin cancer. In the present study, the effects of specific light radiations and cisplatinum on A431 cutaneous squamous cell carcinoma (cSCC) and HaCaT non-tumorigenic cell lines were investigated. Both cell lines were exposed to blue and red light sources for 3 days prior to cisplatinum treatment. Viability, apoptosis, cell cycle progression and apoptotic-related protein expression levels were investigated. The present results highlighted that combined treatment with blue light and cisplatinum was more effective in reducing cell viability compared with single treatments. Specifically, an increase in the apoptotic rate was observed when the cells were treated with blue light and cisplatinum, as compared to treatment with blue light or cisplatinum alone. Combined treatment with blue light and cisplatinum also caused cell cycle arrest at the S phase. Treatment with cisplatinum following light exposure induced the expression of apoptotic proteins in the A431 and HaCaT cell lines, which tended to follow different apoptotic mechanisms. On the whole, these data indicate that blue light combined with cisplatinum may be a promising treatment for cSCC.

Photodynamic and photobiological effects of light-emitting diode (LED) therapy in dermatological disease: an update

Benefit deriving from the use of light is known since ancient time, but, only in the last decades of twentieth century, we witnessed the rapid expansion of knowledge and techniques. Light-emitted diode (LED)-based devices represent the emerging and safest tool for the treatment of many conditions such as skin inflammatory conditions, aging, and disorders linked to hair growth. The present work reviews the current knowledge about LED-based therapeutic approaches in different skin and hair disorders. LED therapy represents the emerging and safest tool for the treatment of many conditions such as skin inflammatory conditions, aging, and disorders linked to hair growth. The use of LED in the treatment of such conditions has now entered common practice among dermatologists. Additional controlled studies are still needed to corroborate the efficacy of such kind of treatment.

Anticancer Efficacy of Photodynamic Therapy with Lung Cancer-Targeted Nanoparticles

Photodynamic therapy (PDT) is a non-invasive and non-surgical method representing an attractive alternative choice for lung cancer treatment. Photosensitizers selectively accumulate in tumor tissue and lead to tumor cell death in the presence of oxygen and the proper wavelength of light. To increase the therapeutic effect of PDT, we developed both photosensitizer- and anticancer agent-loaded lung cancer-targeted nanoparticles. Both enhanced permeability and retention (EPR) effect-based passive targeting and hyaluronic-acid-CD44 interaction-based active targeting were applied. CD44 is a well-known hyaluronic acid receptor that is often introduced as a biomarker of non-small cell lung cancer. In addition, a combination of PDT and chemotherapy is adopted in the present study. This combination concept may increase anticancer therapeutic effects and reduce adverse reactions. We chose hypocrellin B (HB) as a novel photosensitizer in this study. It has been reported that HB causes higher anticancer efficacy of PDT compared to hematoporphyrin derivatives¹. Paclitaxel was selected as the anticancer drug since it has proven to be a potential treatment for lung cancer². The antitumor efficacies of photosensitizer (HB) solution, photosensitizer encapsulated hyaluronic acid-ceramide nanoparticles (HB-NPs), and both photosensitizer- and anticancer agent (paclitaxel)-encapsulated hyaluronic acid-ceramide nanoparticles (HB-P-NPs) after PDT were compared both in vitro and in vivo. The in vitro phototoxicity in A549 (human lung adenocarcinoma) cells and the in vivo antitumor efficacy in A549 tumor-bearing mice were evaluated. The HB-P-NP treatment group showed the most effective anticancer effect after PDT. In conclusion, the HB-P-NPs prepared in the present study represent a potential and novel photosensitizer delivery system in treating lung cancer with PDT.

Improved Targeting of Photosensitizers by Intratumoral Administration of Immunoconjugates

Biodistribution of technetium (99m Tc) labeled hematoporphyrin derivative (HpD, Photosan-3) conjugated to a monoclonal antibody to carcinoembryonic antigen (anti-CEA) was compared following intravenous ( i.v.) and intratumoral ( i.t.) administration in solid Ehrlich ascites tumor bearing mice. Images of mice at different time intervals were acquired after injection of radiolabeled PS-3 in either conjugated or unconjugated forms. Quantitative estimation of the radiolabel in different tissues was performed by selecting the different region of interests (ROIs). Maximum accumulation of both free and antibody conjugated PS-3 following i.v. administration was observed in liver followed by tumor. Tumor/muscle (T/N) ratio was more with free PS-3 compared to conjugated PS-3. Pharmacokinetics of free and conjugated PS-3 was also different with faster accumulation of conjugated PS-3 in the tumor. With intratumoral administration of anti-CEA-PS-3-99m Tc, specific accumulation and retention of the sensitizer was observed in the tumor tissue. Since, direct injection of antibody conjugated photosensitizer into the tumor resulted in longer retention of the dye in the tumor with no accumulation in the normal tissues, the present results imply that the toxicity to normal tissues could be reduced significantly with selective destruction of the tumor following photodynamic treatment with the use of i.t. administration of specific antibodies conjugated to photosensitizers.

Hypocrellin B and paclitaxel-encapsulated hyaluronic acid-ceramide nanoparticles for targeted photodynamic therapy in lung cancer

To increase the therapeutic efficacy of photodynamic therapy (PDT) in treating lung cancer, we developed both photosensitizer and anticancer drug encapsulated hyaluronic acid-ceramide nanoparticles. Based on our previous study, a co-delivery system of photosensitizers and anticancer agents greatly improves the therapeutic effect of PDT. Furthermore, hyaluronic acid-ceramide-based nanoparticles are ideal targeting carriers for lung cancer. In vitro phototoxicity in A549 (human lung adenocarcinoma) cells and in vivo antitumor efficacy in A549 tumor-bearing mice treated with hypocrellin B (HB)-loaded nanoparticles (HB-NPs) or hypocrellin B and paclitaxel loaded nanoparticles (HB-P-NPs) were evaluated. Cell viability assay, microscopic analysis and FACS analysis were performed for the in vitro studies and HB-P-NPs showed enhanced phototoxicity compared with HB-NPs. In the animal study, the tumor volume change and the histological analysis was studied and the anticancer efficacy improved in the order of free HB<HB-NPs<HB-P-NPs. In conclusion, the combination therapy of PDT and chemotherapy, and hyaluronic acid-ceramide nanoparticle-based targeted delivery improved the effects of PDT in lung cancer in mice.

Feasibility for detection of autofluorescent signatures in rat organs using a novel excitation-scanning hyperspectral imaging system

The natural fluorescence (autofluorescence) of tissues has been noted as a biomarker for cancer for several decades. Autofluorescence contrast between tumors and healthy tissues has been of significant interest in endoscopy, leading to development of autofluorescence endoscopes capable of visualizing 2-3 fluorescence emission wavelengths to achieve maximal contrast. However, tumor detection with autofluorescence endoscopes is hindered by low fluorescence signal and limited quantitative information, resulting in prolonged endoscopic procedures, prohibitive acquisition times, and reduced specificity of detection. Our lab has designed a novel excitation-scanning hyperspectral imaging system with high fluorescence signal detection, low acquisition time, and enhanced spectral discrimination. In this study, we surveyed a comprehensive set of excised tissues to assess the feasibility of detecting tissue-specific pathologies using excitation-scanning. Fresh, untreated tissue specimens were imaged from 360 to 550 nm on an inverted fluorescence microscope equipped with a set of thin-film tunable filters (Semrock, A Unit of IDEX). Images were subdivided into training and test sets. Automated endmember extraction (ENVI 5.1, Exelis) with PCA identified endmembers within training images of autofluorescence. A spectral library was created from 9 endmembers. The library was used for identification of endmembers in test images. Our results suggest (1) spectral differentiation of multiple tissue types is possible using excitation scanning; (2) shared spectra between tissue types; and (3) the ability to identify unique morphological features in disparate tissues from shared autofluorescent components. Future work will focus on isolating specific molecular signatures present in tissue spectra, and elucidating the contribution of these signatures in pathologies.

Photodynamic Therapy in Non-Gastrointestinal Thoracic Malignancies

Photodynamic therapy has a role in the management of early and late thoracic malignancies. It can be used to facilitate minimally-invasive treatment of early endobronchial tumours and also to palliate obstructive and bleeding effects of advanced endobronchial tumours. Photodynamic therapy has been used as a means of downsizing tumours to allow for resection, as well as reducing the extent of resection necessary. It has also been used successfully for minimally-invasive management of local recurrences, which is especially valuable for patients who are not eligible for radiation therapy. Photodynamic therapy has also shown promising results in mesothelioma and pleural-based metastatic disease. As new generation photosensitizers are being developed and tested and methodological issues continue to be addressed, the role of photodynamic therapy in thoracic malignancies continues to evolve.

Polymeric nanocarrier systems for photodynamic therapy

Photodynamic therapy (PDT) is an emerging treatment modality that involves the combined action of photosensitizers (PSs) and light for treatment of solid tumor and other diseases. Although this therapeutic method has been considered as an alternative to classical cancer treatments, clinical PDT requires further advances in selectivity and therapeutic efficacy to overcome numerous shortages related to conventional PDT. In this regard, great efforts have been devoted to the development of polymeric nanocarrier-encapsulated PSs for targeted PDT, aiming at improvement of water solubility and tumor-specificity of hydrophobic PSs. Here, we discuss the general concepts and considerations of polymeric nanocarriers for efficient delivery of PSs. In recent, the amphiphilic PS-polymer conjugate-based self-quenchable nanoparticles and PS-polymer-conjugate/quencher nanocomplexes have emerged as an attractive delivery platform for efficient and reliable PDT. They can incorporate and deliver the PS in a photodynamically inactive state but demonstrate cytotoxic effects by tumor environment-sensitive activation mechanisms, so that the photodynamic cancer treatment can achieve maximum target specificity. Here, we report the recent achievements on the development of activatable PS formulations based on PS-polymer conjugates.

A pilot randomized clinical study of the additive treatment effect of photodynamic therapy in breast cancer patients with chest wall recurrence

Purpose

This study investigated the additive effect of photodynamic therapy (PDT) plus traditional radiotherapy (RT) for patients with breast cancer and chest wall recurrence.

Methods

A total of 40 patients with recurrent breast cancer were prospectively randomized to receive RT alone (group A, n=20) or PDT and RT in combination (group B, n=20). Traditional RT at a dose of 50 Gy was delivered in 25 fractions with or without exposure to 5-aminolevulinic acid and red light as PDT.

Results

The response rates were not statistically different between the groups, but more patients achieved a complete response (CR) in group B (50%) than in group A (20%). The median time to CR in group B was significantly shorter than that in group A (109.6 days vs. 175.2 days, p=0.001). Adverse event profiles were not different between the groups.

Conclusion

An additive antitumor effect is demonstrated with additional PDT to RT. This combination therapy might reduce the duration of exposure to RT, but further investigation is warranted.

The in vitro photodynamic effect of laser activated gallium, indium and iron phthalocyanine chlorides on human lung adenocarcinoma cells

Metal-based phthalocyanines currently are utilized as a colorant for industrial applications but their unique properties also make them prospective photosensitizers. Photosensitizers are non-toxic drugs, which are commonly used in photodynamic therapy (PDT), for the treatment of various cancers. PDT is based on the principle that, exposure to light shortly after photosensitizer administration predominately leads to the production of reactive oxygen species for the eradication of cancerous cells and tissue. This in vitro study investigated the photodynamic effect of gallium (GaPcCl), indium (InPcCl) and iron (FePcCl) phthalocyanine chlorides on human lung adenocarcinoma cells (A549). Experimentally, 2 × 10(4)cells/ml were seeded in 24-well tissue culture plates and allowed to attach overnight, after which cells were treated with different concentrations of GaPcCl, InPcCl and FePcCl ranging from 2 μg/ml to 100 μg/ml. After 2h, cells were irradiated with constant light doses of 2.5 J/cm(2), 4.5 J/cm(2) and 8.5 J/cm(2) delivered from a diode laser (λ = 661 nm). Post-irradiated cells were incubated for 24h before cell viability was measured using the MTT Assay. At 24h after PDT, irradiation with a light dose of 2.5 J/cm(2) for each photosensitizing concentration of GaPcCl, InPcCl and FePcCl produced a significant decrease in cell viability, but when the treatment light dose was further increased to 4.5 J/cm(2) and 8.5 J/cm(2) the cell survival was less than 40%. Results also showed that photoactivated FePcCl decreased cell survival of A549 cells to 0% with photosensitizing concentrations of 40 μg/ml and treatment light dose of 2.5 J/cm(2). A 20 μg/ml photosensitizing concentration of FePcCl in combination with an increased treatment light dose of either 4.5 J/cm(2) or 8.5 J/cm(2) also resulted in 0% cell survival. This PDT study concludes that low concentrations on GaPcCl, InPcCl and FePcCl activated with low level light doses can be used for the effective in vitro killing of lung cancer cells.

Novel compounds in the treatment of lung cancer: current and developing therapeutic agents

Lung cancer is the leading cause of cancer-related death in the United States. Though incremental advances have been made in the treatment of this devastating disease during the past decade, new therapies are urgently needed. Traditional cytotoxic agents have been combined with other modalities with improved survival for early-stage patients. Newer cytotoxic agents targeting the same or different mechanisms have been developed at different stages. Optimization of various chemotherapy regimens in different settings is one of the aims of current clinical trials. Some predictive biomarkers (eg, excision repair cross-complementing 1, ERCC1) and histotypes (eg, adenocarcinoma) are found to be associated with resistance/response to some cytotoxic drugs. Another notable advance is the addition of targeted therapy to lung cancer treatment. Targeted agents such as erlotinib and bevacizumab have demonstrated clinical benefits and gained Food and Drug Administration approval for lung cancer. More agents targeting various signaling pathways critical to lung cancer are at different stages of development. Along with the effort of new targeted drug discovery, biomarkers such as epidermal growth factor receptor and anaplastic lymphoma kinase mutations have proven useful for patient selection, and more predictive biomarkers have been actively evaluated in non-small cell lung cancer. The paradigm of lung cancer treatment has shifted towards biomarker-based personalized medicine.

Recent advances in the prevention and treatment of skin cancer using photodynamic therapy

Photodynamic therapy (PDT) is a noninvasive procedure that involves a photosensitizing drug and its subsequent activation by light to produce reactive oxygen species that specifically destroy target cells. Recently, PDT has been widely used in treating non-melanoma skin malignancies, the most common cancer in the USA, with superior cosmetic outcomes compared with conventional therapies. The topical 'photosensitizers' commonly used are 5-aminolevulinic acid (ALA) and its esterified derivative methyl 5-aminolevulinate, which are precursors of the endogenous photosensitizer protoporphyrin IX. After treatment with ALA or methyl 5-aminolevulinate, protoporphyrin IX preferentially accumulates in the lesion area of various skin diseases, which allows not only PDT treatment but also fluorescence diagnosis with ALA-induced porphyrins. Susceptible lesions include various forms of non-melanoma skin cancer such as actinic keratosis, basal cell carcinoma and squamous cell carcinoma. The most recent and promising developments in PDT include the discovery of new photosensitizers, the exploitation of new drug delivery systems and the combination of other modalities, which will all contribute to increasing PDT therapeutic efficacy and improving outcome. This article summarizes the main principles of PDT and its current clinical use in the management of non-melanoma skin cancers, as well as recent developments and possible future research directions.

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).

Understanding patients' lived experience following photodynamic therapy for the treatment of advanced cancer

AIM

To gain an understanding of patients' lived experience following photodynamic therapy (PDT) for the treatment of advanced cancer.

BACKGROUND

Existing literature on PDT tends to be predominantly grounded in basic science and mainly associated with the effect of PDT on the cancer rather than the individual's experience. An appreciation of the impact on patients' day-to-day life may enhance the support and advice offered to patients undergoing this treatment.

METHOD

A Heideggerian hermeneutic phenomenological approach was used as the philosophical framework. Semi-structured interviews were conducted with a purposive sample of six participants. Thematic content analysis was adopted to analyse the data, which yielded six themes.

FINDINGS

Analysis of the data yielded six themes: the impact on day-to-day life; existential meaning; the physical effects of treatment; kaleidoscope of emotions; information gap; and family burden.

CONCLUSION

PDT offers palliation of symptoms for some participants while offering hope of enhanced quality of life. Patients and their families have to be willing and well-informed of the need to comply with the guidance provided by healthcare professionals and information leaflets to avoid any photosensitive reaction. There is a need for education for healthcare professionals as PDT is not well recognized or understood as a treatment for advanced cancer.

In vitro survival of nonsmall cell lung cancer cells following combined treatment with ionizing radiation and photofrin-mediated photodynamic therapy

It has been suggested that combination high dose rate (HDR) intraluminal brachytherapy and photodynamic therapy (PDT) in nonsmall cell lung cancer (NSCLC) may improve efficacy of treatment, reduce toxicity and enhance quality of life for patients. To provide a cellular basis for this we examined the in vitro sensitivity of MRC5 normal lung fibroblasts and four NSCLC cell lines following HDR radiation, PDT and combined HDR radiation and PDT. HDR radiation was cobalt-60 gamma rays (1.5-1.9 Gy min(-1)). For PDT treatment, cells were exposed to 2.5 microg mL(-1) Photofrin for 18-24 h followed by light exposure (20 mW cm(-2)). For combined treatment cells were exposed to Photofrin and then either exposed to light and 15-30 min later exposed to HDR radiation or exposed to HDR radiation and 15-30 min later exposed to light. D(37) values calculated from clonogenic survival curves indicated a six-fold difference in HDR radiation sensitivity and an eight-fold difference in PDT sensitivity. The effect of combined treatment was not significantly different from an additive effect of the individual treatment modalities for the NSCLC cells, but was significantly less than additive for the MRC5 cells. These results suggest an equivalent tumor cell kill may be possible at reduced systemic effects to patients.

Clinical Experience with Autofluorescence Imaging System in Patients with Lung Cancers and Precancerous Lesions

BACKGROUND

It is important to detect preinvasive bronchial lesions before they become invasive cancer, because detection of early cancer is expected to lead to a cure. Autofluorescence bronchoscopy is a useful device in the detection of preinvasive and cancerous lesions. Recently, a new autofluorescence bronchoscopic system, autofluorescence imaging (AFI) system, has been developed.

OBJECTIVES

We evaluated the efficacy of AFI in the diagnosis of precancerous and cancerous lesions.

METHODS

A total of 31 patients underwent both conventional white-light bronchoscopy (WLB) and AFI from January 2002 to September 2004. We evaluated autofluorescence findings using a four-point scale: AFI-I, II, III, and B. The findings in WLB were evaluated on a three-point scale: WLB-I, II, and III. Abnormal areas by WLB and AFI were biopsied for histopathological examinations.

RESULTS

A total of 64 lesions were evaluated. When the AFI-III finding was regarded as positive in AFI and WLB-III as positive in WLB, sensitivity for severe dysplasia or worse was 94.7% with AFI and 73.7% with WLB, respectively.

CONCLUSIONS

AFI is an effective system for the detection of precancerous and cancerous lesions.

Endobronchial photodynamic therapy for lung cancer

BACKGROUND AND OBJECTIVE

Endobronchial photodynamic therapy (PDT) is a minimally invasive technique for the palliation of major airway obstruction from lung cancer, and for the treatment of endobronchial microinvasive lung cancer.

STUDY DESIGN

Results of reported clinical trials were compared, and the author's preliminary results with second generation photosensitizers were also reviewed.

RESULTS

A review of the clinical experience with endobronchial PDT is provided. Potential advantages of PDT include the duration of palliation achieved through the delayed cellular effects of PDT within tumor. Side-effects from FDA-approved photosensitizer (Photofrin, Porfimer sodium, Axcan Scandipharm, Montreal, Quebec) include skin photosensitivity. HPPH (2-[1-hexyloxyethyl]-2 devinyl pyropheophorbide) is an example of a second-generation photosensitize that shows promise in the treatment of lung cancer, and appears to be free from significant skin photosensitivity.

CONCLUSION

PDT is an effective tool for the palliation of endobronchial lung cancers which obstruct the central airways and is also effective for the treatment of central microinvasive carcinoma and carcinoma in situ of the central airways.

Role of photodynamic therapy in unresectable esophageal and lung cancer

The incidence of esophageal cancer has increased dramatically in the Western population in the last two decades. Many of these patients tend to present late in the disease course with symptoms of dysphagia and malnutrition. Thus a majority of patients at presentation may require palliation of their symptoms. Lung cancer is the most common cause of cancer related mortality in the United States. Similar to esophageal cancer, many patients present in advanced stages where surgical resection for cure may not be an option. Endobronchial obstruction from both primary and metastatic neoplasm causes significant morbidity. The modalities, which are currently available for palliation of symptoms include surgery, photodynamic therapy, dilation, external beam radiation, stents, Nd:YAG laser therapy, and brachytherapy. Each of these modalities has their specific advantages and drawbacks. In this article, we discuss the role of photodynamic therapy in the palliation of esophageal and lung cancer.

Photodynamic therapy for the treatment of vertebral metastases in a rat model of human breast carcinoma

The feasibility and efficacy of photodynamic therapy (PDT) for the treatment of vertebral metastases using a minimally invasive surgical technique adapted from vertebroplasty was evaluated in a rodent model. Initial validation included photosensitizer (benzoporphyrin-derivative monoacid-ring A) drug uptake studies and in vitro confirmation of PDT efficacy. Intracardiac injection of human MT-1 breast cancer cells was performed in athymic rats. In 63 rats that developed vertebral metastases 21 days post-inoculation, single treatment of PDT was performed using a parapedicular approach placing an optical fiber adjacent to targeted vertebrae. Two milligrams per kilogram of photosensitizer drug was administered intravenously followed by 150 mW of 690 nm light illumination at varying drug-light intervals and light energies. Histologic and immunohistochemical analysis was performed assessing treatment effect. Local tumor viability and growth was quantified by bioluminescence imaging pre and 48 h post-treatment. PDT demonstrated an ablative effect on vertebral metastases (light energies 25-150 J). The effect varied in proportion to light energy with the greatest anti-tumor effect observed at 150 J using a 3 h drug-light interval. 9/22 rodents in the 3 h drug-light interval developed hindlimb paralysis following treatment, consistent with drug uptake studies demonstrating an increase in spinal cord uptake 3h following drug administration. The observations of paralysis following treatment highlight the importance of closely defining the therapeutic window of treatment in safety and efficacy.

Photodynamic therapy with chlorin e6 for skin metastases of melanoma

BACKGROUND

Photodynamic therapy (PDT) has been successfully applied in clinical settings to destroy neoplasms, but the efficacy of such a treatment is dependent on the type of neoplasm and the photosynthesizer used. Here, we perform a clinical assessment of PDT for skin metastases of pigmented melanoma using chlorin e(6).

STUDY DESIGN/MATERIALS AND METHODS

PDT with chlorin e(6) photosensitizer was administered to 14 patients with skin metastases from melanoma (10 females, four males, mean age 49.6 years). Chlorin e(6) at a dose of 5 mg/kg of patient's weight was intravenously injected. The treatment course consisted of two courses of PDT exposure 1 h after intravenous chlorin e(6) injection and 24 h post-injection. The light energy density for each skin tumor was 80-120 J/cm(2) per treatment, with a light power density of 250-300 mW/cm(2).

RESULTS

All skin melanoma metastases that received PDT showed complete regression with no recurrence during the study period. The complete response of all skin metastases from melanoma occurred in eight cases after one PDT treatment. In the remaining six individuals, tumors required multiple PDT courses prior to complete regression. No cases of photodermatitis were registered. The Karnofsky performance scale score of the patients with skin metastases from melanoma showed no significant difference before and after PDT. No patients had significant changes in blood cell counts that would indicate chlorin e(6) systemic toxic effect. Blood chemistry and urinalysis did not show any evidence of chlorin e(6) renal and hepatic injury.

CONCLUSIONS

PDT with chlorin e(6) for skin metastases from melanoma is effective and well tolerated. Further clinical investigation of PDT with chlorin e(6) is warranted.

The curative potential of intraluminal bronchoscopic treatment for early-stage non-small-cell lung cancer

Bronchoscopic treatment modalities such as lasers, electrocautery, cryotherapy, photodynamic therapy, and brachytherapy are potentially curative for patients with very-early-stage non-small-cell lung cancer (NSCLC) in the central airways. Previously, studies had primarily focused on the effectiveness of surgery, surgical bronchoplasty, and photodynamic therapy. The cure rate of intraluminal bronchoscopic treatment is strongly related to the patient's functional status and tumor stage. Intraluminal tumors are curable bronchoscopically when they are accessible to the fiberoptic bronchoscope, strictly intraluminal, and superficial with visible proximal and distal tumor margins. Early-stage cancer infiltrating deeper into the bronchial wall may already harbor metastases to the regional lymph nodes; hence, curative intraluminal treatment is not feasible. The use of new diagnostic tools (eg, high-resolution computed tomography, autofluorescence bronchoscopy, and endobronchial ultrasound) may improve staging to select the category of patients in whom intraluminal bronchoscopic therapy with curative intent is appropriate. An accurate intraluminal tumor staging will improve our ability to exploit the curative potential of many bronchoscopic techniques for complete tumor eradication in patients with very-early-stage intraluminal NSCLC in their central airways. The use of bronchoscopic treatment as a less morbid alternative than surgical resection will benefit patients most when tumor is detected at the earliest stage possible.

The role of photodynamic therapy in the management of stage I/II NSCLC

There is a resurgence of interest in lung cancer screening, motivated by the fact that many lung cancer patients cannot be cured due to advanced disease at presentation. Lung cancer screening may detect more early stage disease. Very early stage squamous cell type lung cancer in the central tracheobronchial tree can be detected and local bronchoscopic treatments such as photodynamic therapy can be applied if the tumor is strictly intraluminal and nodal disease is absent. So, accurate staging regarding tumor size and nodal disease is much more important than treatment per se. Bronchoscopic treatments are less morbid treatment alternatives than surgery and surgical bronchoplasty, especially for patients suffering from COPD and who have poor cardiovascular status due to their smoking history.

The history of photodetection and photodynamic therapy

Light has been employed in the treatment of disease since antiquity. Many ancient civilizations utilized phototherapy, but it was not until early last century that this form of therapy reappeared. Following the scientific discoveries by early pioneers such as Finsen, Raab and Von Tappeiner, the combination of light and drug administration led to the emergence of photochemotherapy as a therapeutic tool. The isolation of porphyrins and the subsequent discovery of their tumor-localizing properties and phototoxic effects on tumor tissue led to the development of modern photodetection (PD) and photodynamic therapy (PDT). This review traces the origins and development of PD and PDT from antiquity to the present day.

Fluorescence bronchoscopy for early detection of lung cancer: a clinical perspective

The conventional method of bronchoscopy has only a 30% sensitivity to detect early stage cancer in the central airways. For patients with positive sputum cytology who clearly harbor early cancers, repeat and lengthy sessions of bronchoscopies are required for accurate localization of these lesions. This leads to a significant delay in obtaining the diagnosis, postponing an appropriate treatment and reduces the chance for cure. There are valid reasons for improving the detection rate of early stage lung cancers. The number of individuals at risk forms a large population, the outcome of patients treated with early stage cancer has been shown to be better and bronchoscopic treatments, e.g. photodynamic therapy and electrocautery, are currently alternatives for surgical resection. Finding more early stage cancers by screening the population at risk and accurate staging to enable treatment at the earliest stage feasible, may improve the dismal prognosis of many patients. This article deals with the clinical background and current problems in early detection of lung cancer and discusses our expectations regarding new developments in bronchoscopy for early detection, accurate staging and treatment of lung cancer.

Cryotherapy in early superficial bronchogenic carcinoma

BACKGROUND

Treatment of early superficial bronchogenic carcinoma (ESBC) is under debate, and no consensus has been achieved. Different therapeutic methods have been proposed, including surgical resection and endoscopic methods.

STUDY OBJECTIVE

To assess the efficacy of cryotherapy in patients with ESBC.

PATIENTS AND METHODS

Patients included in the study had histologically proven ESBC after fiberoptic bronchoscopy. Cryotherapy was performed through a rigid bronchoscope. Efficacy was assessed by endoscopy with multiple biopsies 1 month after treatment and during the follow-up period. Parameters studied were response to treatment, adverse effects, and survival.

RESULTS

We included 35 patients (34 men and 1 woman). The mean age was 61 +/- 9 years. Multiple locations of ESBC were observed in seven patients (20%). Complete response rate at both 1 month and 1 year was 91% (32 patients). No severe adverse effects were noted. Local recurrence was observed within 4 years in 10 patients (28%). A follow-up period of at least 4 years was available in 22 patients; of them, 11 patients (50%) were long-term survivors.

CONCLUSION

Our results suggest that cryotherapy is an effective method of treatment in patients with ESBC. Due to its relative tolerance compared to surgery, cryotherapy could be proposed as a first-line therapy in this population with high carcinogenic risk.

Early detection of lung cancer with laser-induced fluorescence endoscopy and spectrofluorometry

STUDY OBJECTIVES

We performed a clinical trial of laser-induced fluorescence endoscopy (LIFE) for detection of precancerous lesions and cancer including carcinoma in situ (CIS), which are difficult to detect by white-light bronchoscopy.

DESIGN

Results with LIFE were compared with the criterion standard, white-light bronchoscopy. The evaluation of these endoscopic results spectrofluorometrically was examined, and pixels of LIFE images composed of digital signals for the intensities of red and green were analyzed.

SETTING

Tertiary-level hospital treating referrals and subjects with suspicious results in mass screening.

PATIENTS

We examined 65 subjects with suspected lung cancer by both methods, and performed biopsy on 216 lesions.

RESULTS

The accuracy of diagnosis by white-light bronchoscopy, with histopathologic results as the standard, was 48.6%. The accuracy by LIFE was 72.7%. The sensitivity of conventional bronchoscopy for detection of severe dysplasia (21 biopsy specimens) or cancer (28 biopsy specimens) was 61.2% and specificity was 85.0%. With results by LIFE added, these values were 89.8% and 78.4%, respectively. Of nine patients with CIS, only LIFE showed one lesion, and only LIFE showed the extent of seven of the lesions. The autofluorescence of eight lesions was measured spectrofluorometrically; normal bronchial tissue, severe dysplasia, and cancerous tissue had spectral differences. The red/green intensity of cancers on histograms of LIFE images generally was greater than the ratios for metaplasia or normal bronchial wall.

CONCLUSIONS

Use of both methods should facilitate early detection. Evaluation by spectrofluorometry and analysis of digital signal intensity of results by LIFE make results more objective.

Pharmacokinetics and pharmacodynamics of tetra(m-hydroxyphenyl)chlorin in the hamster cheek pouch tumor model: comparison with clinical measurements

The pharmacokinetics (PK) of the photosensitizer tetra(m-hydroxyphenyl)chlorin (mTHPC) was measured by optical fiber-based light-induced fluorescence spectroscopy (LIFS) in the normal and tumoral cheek pouch mucosa of 29 Golden Syrian hamsters with chemically induced squamous cell carcinoma. Similar measurements were carried out on the normal oral cavity mucosa of five patients up to 30 days after injection. The drug doses were between 0.15 and 0.3 mg per kg of body weight (mg/kg), and the mTHPC fluorescence in the tissue was excited at 420 nm. The PK in both human and hamster exhibited similar behavior although the PK in the hamster mucosa was slightly delayed in comparison with that of its human counterpart. The mTHPC fluorescence signal of the hamster mucosa was smaller than that of the human mucosa by a factor of about 3 for the same injected drug dose. A linear correlation was found between the fluorescence signal and the mTHPC dose in the range from 0.075 to 0.5 mg/kg at times between 8 and 96 h after injection. No significant selectivity in mTHPC fluorescence between the tumoral and normal mucosa of the hamsters was found at any of the applied conditions. The sensitivity of the normal and tumoral hamster cheek pouch mucosa to mTHPC photodynamic therapy as a function of the light dose was determined by light irradiation at 650 nm and 150 mW/cm2, 4 days after the injection of a drug dose of 0.15 mg/kg. These results were compared with irradiations of the normal oral and normal and tumoral bronchial mucosa of 37 patients under the same conditions. The reaction to PDT of both types of human mucosae was considerably stronger than that of the hamster cheek pouch mucosa. The sensitivity to PDT became comparable between hamster and human mucosa when the drug dose for the hamster was increased to 0.5 mg/kg. A significant therapeutic selectivity between the normal and neoplastic hamster cheek pouch was observed. Less selectivity was found following irradiations of normal mucosa and early carcinomas in the human bronchi. The pharmacodynamic behavior of mTHPC was determined by test irradiations of the normal mucosa of hamsters and patients between 6 h and 8 days after injection of 0.5 and 0.15 mg/kg in the hamsters and the patients, respectively. The normal hamster cheek pouch showed a maximum response to irradiation 6 h after injection and then decreased continuously to no observable reaction at 8 days after injection. The reaction of the normal human oral mucosa, however, showed an increasing sensitivity to the applied light between 6 h and 4 days after mTHPC injection and then decreased again at 8 days. The hamster model with the chemically induced early squamous cell cancer in the cheek pouch thus showed some similarity to the early squamous cell cancer of the human oral mucosa considering the PK. However, a quantitative difference in fluorescence signal for identical mTHPC doses as well as a significant difference in pharmacodynamic behavior were also observed. The suitability of this animal model for the optimization of PDT parameters in the clinic is therefore limited. Hence great care must be taken in screening new dyes for PDT of early squamous cell cancer of the upper aerodigestive tract based upon observables in the hamster cheek pouch model.

Use of alkaline Comet assay to assess DNA repair after m-THPC-PDT

Photodynamic therapy (PDT) with Photofrin has already been authorized for certain applications in Japan, the USA and France, and powerful second-generation sensitizers such as meta-(tetrahydroxyphenyl) chlorin (m-THPC) are now being considered for approval. Although sensitizers are likely to localize within the cytoplasm or the plasma membrane, nuclear membrane can be damaged at an early stage of photodynamic reaction, resulting in DNA lesions. Thus, it is of critical importance to assess the safety of m-THPC-PDT, which would be used mainly against early well-differentiated cancers. In this context, m-THPC toxicity and phototoxicity were studied by a colorimetric MTT assay on C6 cells to determine the LD50 (2.5 microg/ml m-THPC for 10 J/cm2 irradiation and 1 microg/ml for 25 J/cm2 irradiation) and PDT doses inducing around 25% cell death. Single-cell electrophoresis (a Comet assay with Tail Moment calculation) was used to evaluate DNA damage and repair in murine glioblastoma C6 cells after LD25 or higher doses for assays of PDT. These results were correlated with m-THPC nuclear distribution by confocal microspectrofluorimetry. m-THPC failed to induce significant changes in the Tail Moment of C6 cells in the absence of light, whereas m-THPC-PDT induced DNA damage immediately after irradiation. The Tail Moment increase was not linear (curve slope being 43 for 0-1 microg/ml m-THPC and 117 for 1-3 microg/ml), but the mean value increased with the light dose (0, 10 or 25 J/cm2) and incubation time (every hour from 1 to 4 h) for an incubation with m-THPC 1 microg/ml. However, cultured murine glioblastoma cells were capable of significant DNA repair after 4 h, and no residual DNA damage was evident after 24-h post-treatment incubation at 37 degrees C. An increase in the light dose appeared to be less genotoxic than an increase in the m-THPC dose for similar toxicities. Our results indicate that m-THPC PDT appears to be a safe treatment since DNA repair seemed to not be impaired and DNA damage occurred only with lethal PDT doses. However, the Comet assay cannot give us the certainty that no mutation, photoadducts or oxidative damage have been developed so this point would be verified with another mutagenicity assay.

Evaluation and endoscopic palliation of cholangiocarcinoma. Management of cholangiocarcinoma

Patients with a cholangiocarcinoma usually develop symptoms of biliary obstruction which dominate the course of their illness. At presentation, the diagnosis may be difficult to establish due to the desmoplastic nature of this tumor. Location and extent of the tumor, however, are more effectively evaluated by current radiologic techniques. Following these staging procedures, most patients are found to be unsuitable for curative resection. Therefore, establishing effective biliary drainage to relieve symptoms of obstruction becomes the most critical therapeutic goal in these patients. In the past, surgical biliary bypass procedures were advocated, but were associated with high perioperative morbidity and mortality rates. Endoscopic biliary stenting produces quick and effective relief of symptoms from biliary obstruction due to cholangiocarcinoma. Initially, successful biliary drainage is possible in most patients. However, subsequent stent occlusion or spread of tumor into nonstentable intrahepatic ducts leads to recurrent jaundice. Local therapies including (192)Ir brachytherapy and photodynamic therapy may prevent or postpone these problems.

Fluorescence pharmacokinetics of Lutetium Texaphyrin (PCI-0123, Lu-Tex) in the skin and in healthy and tumoral hamster cheek-pouch mucosa

We have investigated the pharmacokinetics (PK) of Lutetium Texaphyrin (Lu-Tex), a second-generation photosensitizer, in the Syrian hamster cheek pouch early cancer model. Ten male hamsters, five with chemically induced early squamous cell cancer of the left cheek pouch, received an intracardiac injection of a 10 mg/ml Lu-Tex solution, resulting in a dose of 12 mg Lu-Tex per kg of bodyweight. The PK of the dye have been measured during the 24 h following the injection with an optical-fiber-based spectrofluorometer on the ventral skin, the healthy and the tumoral cheek-pouch mucosa. The Lu-Tex fluorescence is excited at 460 nm and detected around 740 nm. All the measurements yield very similar pharmacokinetic curves. The fluorescence intensity reaches a maximum between two and three hours after the injection and, at its maximum, it is consistently higher (up to 1.5 times) on the tumor than on the healthy mucosa. It remains smaller on the skin than on cheek-pouch mucosa. After 24 h, the Lu-Tex fluorescence is no longer detectable either on the skin, on the lesion or on the healthy mucosa. Moreover, Lu-Tex clearly displays a significant fluorescence selectivity between early carcinoma and healthy mucosa in this model. Furthermore, the inter-animal fluctuations of the fluorescence signal are small (+/-16% on the tumor-bearing mucosa). Eight-minute-long skin-irradiation tests have been performed 24 h after the injection of the Lu-Tex on the ventral skin of 16 additional animals with a solar simulator. No reaction is observed, either macroscopically or microscopically, which further demonstrates, as suggested by the fluorescence measurements, that this photosensitizer is significantly cleared from the skin after 24 h.

Endoscopic treatment of early-stage lung cancer

BACKGROUND

Disease-free survival after surgical resection of lung carcinoma in situ has been reported as over 90%. After resection of stage IA non-small cell lung cancer, survival at 5 years is approximately 60% to 70%. If endoscopic or bronchoscopic treatments of early-stage lung cancer can provide similar disease-free survival with less perioperative mortality, morbidity, and cost, then they may be alternative front-line therapies.

METHODS

The authors review early-stage lung cancer detection by fluorescence bronchoscopy and the potential treatment of this disease by endoscopic techniques (photodynamic therapy, brachytherapy, Nd:YAG laser, electrocautery, and cryotherapy).

RESULTS

Several reports have noted improved outcomes using endoscopic therapies for early-stage lung cancer, but insufficient data preclude firm conclusions regarding the role of fluorescence bronchoscopy, endobronchial brachytherapy, or electrocautery in early-stage lung cancer. Other than resection, photodynamic therapy may represent the best approach at this time. The principal indication for laser bronchoscopy is palliation of central airway obstruction.

CONCLUSIONS

The identification of early-stage lung cancer provides no advantage if we have little to offer the patient short of traditional therapy. The value of newer treatment techniques and methods requires verification.

In vitro and in vivo evaluation of hypericin for photodynamic therapy of equine sarcoids

The therapeutic potential of the photodynamic compound, hypericin, in the treatment of equine sarcoids was evaluated. The in vitro cytotoxicity was assessed using three equine cell lines and the observed phototoxic effect was comparable to that on different highly sensitive human cell lines and significantly influenced by the energy density used although independent of the cell type. The in vivo antitumoural action of photodynamic therapy using hypericin was evaluated on three equine sarcoids in a donkey. Four intratumoural injections were given and the tumours were illuminated daily during 25 days. An 81% reduction in tumour volume was obtained at the end of therapy and 2 months later, a 90% reduction was observed. Further experimental work should be performed, but these results suggest that photodynamic therapy using hypericin has a potential for the non-invasive treatment of equine sarcoids.

Immunohistochemical analysis of Bcl-2 protein in early squamous cell carcinoma of the bronchus treated with photodynamic therapy

Photodynamic therapy (PDT) in early squamous cell carcinoma of the bronchus has been shown to result in complete response (CR) and cure. However, local recurrence after PDT develops frequently even after complete remission. Because the effect of PDT had been reported to depend on apoptosis, and apoptosis is inhibited by bcl-2 protein, the relationship between the expression of bcl-2 protein and local recurrence after PDT was examined immunohistochemically. From 1983 to 1997, 50 patients with 59 early squamous cell carcinoma of the bronchus received PDT, and a CR was obtained in 43 lesions (72.8%). As there was no recurrence among tumours that were disease-free for more than 2 years, in this study the tumours were defined as cured when recurrence did not occur 2 years subsequent to the receiving of PDT. Of these CR lesions, 31 carcinomas (53.4%) resulted in a cure. Bcl-2 immunoreactivity was detected in 23 tumours (46.9%) and p53 immunoreactivity was detected in 22 tumours (44.9%). When all tumours were divided into either a large tumour with a longitudinal tumour length of 10 mm or more, or a small tumour with a length of less than 10 mm, the large tumour expressed more bcl-2 protein than the small tumour (P = 0.0155). The degree of bcl-2 expression was significantly related with tumour size (P = 0.0155). The expression of bcl-2 and p53 protein was not associated with the cure rate due to PDT. Tumour length and T status in TNM staging were significantly related to the cure by univariate analysis. T status was the only predictor of the cure according to mutivariate analysis. Of 42 CR lesions, the expression of neither bcl-2 nor p53 protein was associated with local recurrence; only T status was significantly associated (P = 0.008). The relationship between the expression of oncoprotein and local recurrence after PDT was not documented in this study. The success of PDT may depend on the exact assessment of tumour size under optimized PDT illumination.

Fine-needle interstitial photodynamic therapy of the lung parenchyma: photosensitizer distribution and morphologic effects of treatment

STUDY OBJECTIVE

To look at the effect of interstitial photodynamic therapy (PDT) in normal lung parenchyma to assess its potential for treating localized, peripheral lung tumors.

DESIGN

Studies were performed on normal Wistar rats using the photosensitizer meso-tetrahydroxyphenyl chlorine. Drug distribution was measured by fluorescence microscopy on tissue sections. Light was delivered to the lungs via a single fiber inserted percutaneously under x-ray control and the PDT effect studied in animals killed at times up to 6 months later.

RESULTS

Fluorescence studies showed that the drug was initially distributed throughout the lung, but was later predominantly in the vasculature, bronchi, and macrophages. PDT produced sharply defined zones of hemorrhagic necrosis up to 12 mm in diameter that healed with regeneration of bronchial epithelium and local fibrosis. Different histologic effects were seen between drug light intervals of 1 and 3 days. Treatment was well tolerated, there was a low incidence of pneumothorax, and as long as the fiber tip was within the lung parenchyma, there was no damage to adjacent tissues.

CONCLUSION

Interstitial PDT produces zones of necrosis in normal lung that heal safely by a percutaneous technique without affecting adjacent areas of untreated lung. If the lesion size can be increased by using multiple fibers, this could be a promising new technique for treating localized, peripheral lung cancers in patients who are unfit for surgery.