Photodynamic therapy for treatment of head and neck cancer

Current Photodynamic Therapy for Glioma Treatment: An Update

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

Evaluation of the effects of photodynamic therapy consisted of the blue laser and zinc oxide QDs on MDA-MB-231 cancer cells by inhibiting cancer markers and inducing apoptosis

The increasing number of cancer patients has cast attention on developing new anti-cancer modalities. Photodynamic therapy is a safe anti-cancer approach, which encompasses (1) local administration of a photosensitizer and (2) light irradiation. Zinc oxide (ZnO) quantum dots (QDs) are photosensitizers that can be utilized for this purpose. In the present study, to better appreciate the likely more efficient cytotoxic effect of the combination of ZnO QDs and the visible 470-nm blue light in comparison to the QDs alone, several assays were to be conducted upon breast cancer MDA-MB 231 cells. MTT assay showed that in certain groups the combination displayed higher cytotoxic effects compared to those following QD treatment alone. LDH leakage and lipid peroxidation rates by the combination were significantly higher than treatment with either the blue laser or QDs. Although the combination managed to meaningfully reduce the number of colonies and CAT activity compared to QD treatment, there were no palpable differences between them. Lastly, the combination was able to increase the apoptotic genes, including BAX, TP53, caspase 3, and caspase 9 compared to QD, while, in the case of Bcl-2, an anti-apoptotic gene, none of the groups managed to make any tangible differences on its expression levels. Our findings propose that there may be synergistic effects between the blue laser and QD that can possibly be adopted in anti-cancer therapy in the future. However, further investigations regarding this matter are of the essence.

Systematic Review of Photodynamic Therapy in Gliomas

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

Nanotechnology Advances in the Detection and Treatment of Cancer: An Overview

Over the last few years, progress has been made across the nanomedicine landscape, in particular, the invention of contemporary nanostructures for cancer diagnosis and overcoming complexities in the clinical treatment of cancerous tissues. Thanks to their small diameter and large surface-to-volume proportions, nanomaterials have special physicochemical properties that empower them to bind, absorb and transport high-efficiency substances, such as small molecular drugs, DNA, proteins, RNAs, and probes. They also have excellent durability, high carrier potential, the ability to integrate both hydrophobic and hydrophilic compounds, and compatibility with various transport routes, making them especially appealing over a wide range of oncology fields. This is also due to their configurable scale, structure, and surface properties. This review paper discusses how nanostructures can function as therapeutic vectors to enhance the therapeutic value of molecules; how nanomaterials can be used as medicinal products in gene therapy, photodynamics, and thermal treatment; and finally, the application of nanomaterials in the form of molecular imaging agents to diagnose and map tumor growth.

DWI for Monitoring the Acute Response of Malignant Gliomas to Photodynamic Therapy

BACKGROUND AND PURPOSE

Photodynamic therapy is a novel treatment that provides effective local control, but little is known about photodynamic therapy-induced changes on MR imaging. The aim of this study was to assess the utility of DWI and ADC in monitoring the response of malignant gliomas to photodynamic therapy.

MATERIALS AND METHODS

Time-dependent changes in DWI and ADC values after photodynamic therapy were analyzed in a group that received photodynamic therapy in comparison with a group that did not.

RESULTS

Twenty-four patients were enrolled (photodynamic therapy, n = 14; non-photodynamic therapy, n = 10). In all patients who received photodynamic therapy, linear high signals on DWI in the irradiated area were detected adjacent to the resection cavity and were 5-7 mm in depth from 1 day posttreatment and disappeared in about 30 days without any neurologic deterioration. The non-photodynamic therapy group did not show this change. The photodynamic therapy group had significantly lower ADC values from 1 day posttreatment (P < .001), which increased steadily and disappeared by 30 days. There was no decline or time-dependent change in ADC values in the non-photodynamic therapy group.

CONCLUSIONS

The acute response of malignant gliomas to photodynamic therapy was detected as linear high signals on DWI and as a decrease in ADC values. These findings were asymptomatic and transient. Although the photodynamic therapy-induced acute response on MR imaging disappeared after approximately 30 days, it may be helpful for confirming the photodynamic therapy-irradiated area.

Advanced smart-photosensitizers for more effective cancer treatment

Photodynamic therapy (PDT) based upon the use of light and photosensitizers (PSs) has been used as a novel treatment approach for a variety of tumors. It, however, has several major limitations in the clinic: poor water solubility, long-term phototoxicity, low tumor targeting efficacy, and limited light penetration. With advances in nanotechnology, materials science, and clinical interventional imaging procedures, various smart-PSs have been developed for improving their cancer-therapeutic efficacy while reducing the adverse effects. Here, we briefly review state-of-the-art smart-PSs and discuss the future directions of PDT technology.

Photodynamic Therapy in Dentistry

Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy, or photochemo-therapy, involves the use of a photoactive dye (photosensitizer) that is activated by exposure to light of a specific wavelength in the presence of oxygen. The transfer of energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen species, such as singlet oxygen and free radicals. These very reactive chemical species can damage proteins, lipids, nucleic acids, and other cellular components. Applications of PDT in dentistry are growing rapidly: the treatment of oral cancer, bacterial and fungal infection therapies, and the photodynamic diagnosis (PDD) of the malignant transformation of oral lesions. PDT has shown potential in the treatment of oral leukoplakia, oral lichen planus, and head and neck cancer. Photodynamic antimicrobial chemotherapy (PACT) has been efficacious in the treatment of bacterial, fungal, parasitic, and viral infections. The absence of genotoxic and mutagenic effects of PDT is an important factor for long-term safety during treatment. PDT also represents a novel therapeutic approach in the management of oral biofilms. Disruption of plaque structure has important consequences for homeostasis within the biofilm. Studies are now leading toward selective photosensitizers, since killing the entire flora leaves patients open to opportunistic infections. Dentists deal with oral infections on a regular basis. The oral cavity is especially suitable for PACT, because it is relatively accessible to illumination.

Preclinical validation of talaporfin sodium-mediated photodynamic therapy for esophageal squamous cell carcinoma

Photodynamic therapy (PDT) kills cancer cells via a photochemical reaction mediated by an oncotropic photosensitizer. Herein, we performed an experimental preclinical study to validate the anti-tumour effect of talaporfin sodium-mediated PDT (t-PDT) for esophageal squamous cell carcinoma (ESCC) cells. We used human ESCC cells derived from various differentiation grades or resistant to 5-fluorouracil (5-FU). The cytotoxic effect of t-PDT was determined by evaluating cell viability, apoptosis and generation of reactive oxygen species (ROS) and DNA double-strand breaks. Furthermore, the anti-tumour effect of t-PDT was assessed using an anchorage-independent cell-growth assay and xenograft transplantation models. t-PDT induced potent cytotoxicity in ESCC cells independent of their differentiation grade or 5-FU resistance. Moreover, t-PDT induced robust apoptosis, as indicated by cell shrinkage, perinuclear vacuolization, nuclear fragmentation and induction of annexin V-positive cells. This apoptotic response was accompanied by concurrent activation of ROS, and induction of DNA double-strand breakage. Importantly, t-PDT suppressed efficiently anchorage-independent cell growth as well as ESCC-xenografted tumor formation. In aggregate, t-PDT showed anti-tumor potential for ESCC cells with various histological grades or chemoresistance, providing a novel translational rationale of t-PDT for the treatment of ESCC.

Photodynamic therapy of head and neck cancers

Over 1,500 patients have been treated with PDT using Photofrin, HPD, ALA, or Foscan for head and neck cancers. These patients include a mixture of presentations including primary, recurrent, and metastatic lesions. The predominant histology is squamous cell carcinoma, but other histologies treated include mucosal melanoma, Kaposi's sarcoma, adenocarcinoma, metastatic breast carcinoma, and adenoid cystic carcinoma. Several multi-institutional phase II clinical trials evaluating PDT treatment of head and neck cancers have demonstrated the efficacy of this minimally invasive therapy in the treatment of early oropharyngeal primary and recurrent cancers as well as the palliative treatment of refractory head and neck cancers. Patients with early stage cancers or early recurrences in the oral cavity and larynx (Cis, T1, T2) tend to have an excellent response to PDT. Of 518 patients treated with Cis, T1, or T2 cancers of the oral cavity, larynx, pharynx, and nasopharynx, 462 (89.1%) obtained a complete clinical response after one PDT treatment. Laryngeal cancers, comprising 171 patients in this group, obtained a durable complete response rate of 89% with up to a 16-year follow-up. Photodynamic therapy is as effective as conventional therapies for the treatment of early (Cis, T1, T2) squamous cell cancers of the head and neck. It is also a promising therapy to be used in association with surgery to increase tumor-free margins and therefore increase cure rates.

Terapia fotodinâmica em dermatologia: princípios básicos e aplicações

A terapia fotodinâmica envolve a administração de uma droga fotossensibilizante e sua ativação subsequente pela luz de comprimento de onda correspondente ao espectro de absorção do fotossensibilizador. Atualmente, a terapia fotodinâmica tópica é aprovada para o tratamento de condições oncológicas cutâneas como queratoses actínicas, doença de Bowen e carcinoma basocelular superficial em diversos países do mundo. Estudos multicêntricos controlados e randomizados demonstram a alta eficácia e resultado cosmético final superior dessa modalidade terapêutica em relação aos tratamentos convencionais. Para condições cutâneas não oncológicas, como acne vulgar, verrugas virais e esclerodermia localizada, há também relatos e série de casos confirmando o potencial terapêutico da terapia fotodinâmica. O desenvolvimento de fotossensibilizantes tópicos, ácido 5-aminolevulínico (ALA) ou seu metiléster (MAL), frente aos derivados da hematoporfirina de aplicação sistêmica, permitiu um grande avanço na popularidade da TFD na dermatologia, uma vez que tanto ALA quanto MAL tópicos não induzem mais fotossensibilidade generalizada prolongada. A produção de intermediários reativos de oxigênio, como oxigênio singlet, depende da concentração, da localização do fotossensibilizante no tecido alvo, assim como da dose de luz utilizada. Tanto as lâmpadas de amplo espectro quanto os LEDs (do inglês light emitting diodes) constituem fontes de luz adequadas para que os efeitos citotóxicos da terapia fotodinâmica resultem na destruição do tumor ou seus efeitos imunomodulatórios atuem melhorando as condições inflamatórias cutâneas.

Performance of a dedicated light delivery and dosimetry device for photodynamic therapy of nasopharyngeal carcinoma: phantom and volunteer experiments

The objective of this study was to develop a light delivery and measurement device for photodynamic therapy (PDT) in the nasopharyngeal cavity, which achieves a homogeneous and reproducible fluence rate distribution to a target area and provides proper shielding of predefined risk areas.

MATERIALS AND METHODS

A flexible silicone applicator was developed, incorporating light delivery and dosimetry fibers. The applicator can be inserted through the mouth and fixed in the nasopharyngeal cavity. Tissue optical phantoms were prepared on the basis of optical properties measured in vivo using diffuse reflectance spectroscopy (DRS). The fluence rate over the length of the applicator surface was measured in air, in tissue optical phantoms and in five healthy volunteers.

RESULTS

The fluence rate distribution over the applicator surface in air and tissue optical phantom was found to be more homogeneous (SD/mean 3.8% and 18.3%, respectively) than the fluence rate distribution in five volunteers (SD/mean ranging from 19% up to 52%). The maximum observed fluence rate build-up in the nasopharynx varied between subjects and ranged from a factor of 4.1-6.9. Shielding of the risk area such as the soft palate and tongue was effective.

CONCLUSIONS

In air and in tissue optical phantoms the fluence rate distribution of the device was highly homogeneous. The observed inter-subject and intra-subject variations in fluence rate in healthy volunteers originated from differences in optical properties and nasopharyngeal geometry. Light delivery based on a single tissue surface measurement will not be adequate. In situ dosimetric measurements are required to determine the light fluence delivered to a geometrically complex site such as the nasopharynx. These observations should be taken in consideration when developing light applicators for PDT of the nasopharynx and other non-uniform surfaces.

Photodynamic therapy treatment of early oral and laryngeal cancers

Photodynamic therapy (PDT) is a nonsurgical, minimally invasive treatment that uses a light source to activate light-sensitive drugs or photosensitizers in the treatment of cancer and other diseases. PDT has been successfully employed to treat early carcinomas of the oral cavity and larynx preserving normal tissue and vital functions of speech and swallowing. Two hundred seventy-six patients with early carcinomas of the oral cavity and larynx were treated from 1990 to 2006. Cure rates with a single treatment for early laryngeal and oral cancers were 91% and 94%, respectively. PDT is an effective primary and alternative treatment modality for early oral cavity and laryngeal cancers.

Photodynamic therapy using talaporfin sodium for synovial membrane from rheumatoid arthritis patients and collagen-induced arthritis rats

We investigated the efficacy of photodynamic therapy (PDT) using talaporfin sodium as a new method of synovectomy for rheumatoid arthritis (RA). We first used RA synovial membrane (RASM) for in vitro and in vivo study. The RASM was obtained from patients with RA during total knee replacement. In the in vitro study, RA fibroblast-like synoviocytes (RASCs) obtained from the RASM were examined by fluorescent microscopy to measure the intracellular localization of talaporfin sodium. The cells were then subjected to PDT, and their viability was examined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium inner salt assay. In the in vivo assay, RASM was obtained as described above, grafted onto severe combined immunodeficiency (SCID) mice and subjected to PDT. The damaged area of RASM was evaluated histologically at 1 day after PDT. Next, we performed a separate experiment using rats with collagen-induced arthritis (CIA). After intra-articular injection of talaporfin sodium, the concentration of talaporfin sodium accumulated in the CIA synovial membrane (CIASM) was compared with that in cartilage, periarticular muscle, and skin. We then performed PDT with intra-articular injection of talaporfin sodium and intra-articular irradiation. The damaged area of the CIASM was measured at 1 day after the PDT, and the articular histological and radiological changes of the ankle were observed at 56 days after the PDT. In RASM, talaporfin sodium accumulated in lysosomes in vitro, and the phototoxicity to RASCs in vitro and to RASM grafted onto SCID mice in vivo depended on the concentration of talaporfin sodium and the laser energy. In CIA rats, there was a greater accumulation of talaporfin sodium in the CIASM than in normal tissue. The CIASM was selectively damaged at 1 day after the PDT, and the bone and cartilage destruction were ameliorated at 56 days after the PDT. In conclusion, PDT using talaporfin sodium might be a new method for synovectomy in patients with RA.

Advances in photodynamic therapy for the treatment of head and neck cancers

Photodynamic therapy (PDT) is an FDA-approved minimally invasive medical treatment modality that utilizes light in the presence of oxygen to activate photosensitizing agents that are relatively selectively concentrated in abnormal or neoplastic cells resulting in cell death. At the present time, PDT has been approved for clinical treatment in the United States, European Union, Canada, Russia, and Japan. In the United States, US Food and Drug administration approval has been given for the use of PDT in the treatment of Barrett's esophagus, obstructing esophageal carcinoma and early and obstructing tracheobronchial carcinoma using the photosensitizer Photofrin; actinic keratosis using the photosensitizer Levulan (aminolevulinic acid); and macular degeneration using the photosensitizer BPD. In the EU the above noted indications have also been approved in addition to the treatment of early head and neck cancers and palliative treatment of head and neck cancer using the photosensitizer Foscan; and treatment of basal and squamous cell skin cancers using the photosensitizer Metvix.

Griseofulvin enhances the effect of aminolevulinic acid-based photodynamic therapy in vitro

OBJECTIVE

In this study, we investigated whether or not griseofulvin (GF), which is an antimycotic widely used for the oral treatment of skin fungal infections, enhanced the effect of aminolevulinic acid-based photodynamic therapy (ALA-PDT) in vitro, using several tumor cell lines.

METHODS

A human squamous cell carcinoma line (KB), two human osteosarcoma cell lines from mandible (HOSM-1, HOSM-2), and the human gingiva-derived fibroblast line (HF), representing normal cells, were used. GF enhancement of ALA-PDT was evaluated by comparing the effect of ALAin combination with GF to the effect of ALAalone (GF enhancement rate of ALA-PDT). Also, the effect of GF on intracellular accumulation of protoporphyrin IX (PpIX) was evaluated by comparing the intracellular accumulation of PpIX in the ALA and GF combined treatment with that of ALA treatment alone (pGF enhancement rate of intracellular PpIX).

RESULTS

GFenhancement rate of ALA-PDT was 2.51 in KB cells, and 1.65 and 1.27 in HOSM-1 and HOSM-2 cells, respectively. GF enhancement rates of intracellular PpIX were 1.94 in KB cells, 1.53 in HOSM-1 cells, and 1.19 in HOSM-2 cells. GF enhancement rate of intracellular PpIX followed the same trends as the levels of GF enhancement rate of ALA-PDT in the different cell types. For HF, a large effect was not revealed in this study.

CONCLUSION

The present study, although preliminary, strongly suggests that concomitant treatment with ALAand GF may be very useful to enhance the effect of ALA-PDT.

In vivo fluence rate measurements during Foscan-mediated photodynamic therapy of persistent and recurrent nasopharyngeal carcinomas using a dedicated light applicator

The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy-induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan absorption.

Evaluation of Firefly Luciferase Bioluminescence Mediated Photodynamic Toxicity in Cancer Cells

PURPOSE

This work investigated whether fLuc-catalyzed oxidation of D-luciferin generates sufficient light to induce photodynamic toxicity in cancer cells.

PROCEDURES

Light emission was assessed via cooled CCD (charge-coupled device) camera. Parental and fLuc expressing cancer cells were exposed to subtoxic concentrations of photosensitizers (Rose Bengal or hypericin) and D-luciferin, sunlight, or lamplight. Toxicity was assessed by MTT assay.

RESULTS

fLuc expressing cells emitted up to 500-fold higher levels of photons than parental cell lines. Although exposure to photosensitizer and sunlight reduced survival of various cell lines, survival of fLuc expressing cells incubated with photosensitizer and D-luciferin, or photosensitizer and lamplight, did not differ significantly from parental or untreated cells.

CONCLUSIONS

Contesting recent reports, fLuc bioluminescence does not generate sufficient photons to induce Rose Bengal or hypericin photodynamic toxicity in a range of malignant and nonmalignant cell lines, and is not suitable as a generalizable approach to antineoplastic therapy.

Clinical photodynamic therapy of head and neck cancers-A review of applications and outcomes

As local control is tantamount to cure in head and neck cancer, an aggressive regimen of surgery and radiation remains the standard of care for most patients. Despite significant technical advances, these treatments are highly morbid. Further, patients who fail treatment have limited salvage options. Photodynamic therapy (PDT) and photodiagnosis (PD) of head and neck cancer offer significant potential for improved outcomes in a myriad of clinical indications ranging from in situ to recurrent disease. However, despite promising results, these modalities remain at the fringe of head and neck treatment options. Photofrin(®), Photosan and Foscan(®) are photosensitizers used clinically in head and neck PD/PDT. In addition, aminolevulinic acid (ALA), which gives origin to Protoporphyrin IX, an endogeneous photosensitizer, is also used for PD/PDT. We review the clinical literature on these photosensitizers to assist in the integration of these important modalities into the mainstream of head and neck oncological therapy.

Pharmacokinetics and clinical effects of mono-l-aspartyl chlorin e6 (NPe6) photodynamic therapy in adult patients with primary or secondary cancer of the skin and mucosal surfaces

BACKGROUND/PURPOSE

Mono-L-aspartyl chlorin e6 (NPe6) is a photosensitizer that exhibits chemical purity, absorption at 664 nm wavelength and may be useful in photodynamic therapy (PDT).

METHODS

This open label phase I clinical trial at the University of California, Davis Medical Center examined the pharmacokinetic properties of Npe6 and clinical response to PDT with this photosensitizer. A single intravenous dose of Npe6 was administered to 14 cancer patients with superficial malignancies (basal cell carcinoma = 22 lesions, squamous cell cancer = 13 lesions, papillary carcinoma = 14 lesions). Patients received one of five ascending doses (0.5 mg/kg (n = 4), 1.0 mg/kg (n = 3), 1.65 mg/kg (n = 3), 2.5 mg/kg (n = 3), or 3.5 mg/kg (n = 1)) 4-8 h prior to light activation. The total light dose (range 25-200 J/cm2) depended on the tumor shape and size. Light was delivered using an argon-pumped tunable dye laser. Serum NPe6 concentrations were measured over a 28-day period. The toxicity and cutaneous clinical efficacy of NPe6 were observed.

RESULTS

Four weeks post-PDT, 20 of 22 basal cell carcinoma tumors (91%) showed a complete response. Eighteen of 27 other malignant cutaneous tumors showed a complete (n = 15/27, 56%) or partial (n = 3/27, 11%) response. Fewer non-responders were seen at an Npe6 dose level of 1.65 mg/kg or higher. Only 2 of 14 patients experienced an adverse event that was definitely related to NPe6 administration. Photosensitivity resolved within 1 week of NPe6 dosing in 12 of 14 patients. Analysis of serum levels of 11 individual patients indicated that a two-compartment model with a residual phase best fits the data. The mean alpha, beta, and terminal half-lives were 8.63+/-2.92, 105.90+/-37.59 and 168.11+/-53.40 h (+/-1 SD), respectively. The observed mean volume of distribution was 5.94+/-2.55 l, and the mean clearance was 0.0394+/-0.0132 l/h. These values were independent of the dose administered.

CONCLUSION

The photosensitizer, NPe6, was well tolerated with minimal phototoxic side effects, and demonstrated preliminary efficacy against cutaneous malignancies.

Efficacy of combined photodynamic and hyperthermic therapy with a new light source in an in vivo osteosarcoma tumor model

OBJECTIVE

In this study, we investigated the efficacy of Super Lizer (SL) as a new light source in photodynamic therapy (PDT) with hyperthermia in an in vivo osteosarcoma tumor model.

MATERIALS AND METHODS

Nude mice in three study groups (PDT only, PDT with hyperthermia in low energy, and PDT with hyperthermia in high energy) and three control groups (no treatment, photosensitizer only, and hyperthermia only) were implanted subcutaneously with human osteosarcoma cells and injected with a photosensitizing hematoporphyrin derivative (HPD) at a total dose of 10 mg/kg, in all study groups and in control group 2. At 72 h after light treatment, mice were sacrificed.

RESULTS

The tumor volume growth rates in the heat-only (1.50) and PDT-only (1.40) groups were significantly lower than the growth rate in the no-treatment group (1.82). Further, the tumor volume growth rate in the PDT with hyperthermia in high-energy group (1.19) was significantly lower than in the heat- or PDT-only groups.

CONCLUSION

Although non-laser PDT, including SL-PDT, may be beneficial only in the treatment of superficial tumors because of limited light penetration, PDT combined with hyperthermia may extend the utility of PDT in antitumor treatment. The use of SL as a new light source in PDT may significantly advance antitumor therapy due to its simplicity, ease, and cost benefit.

Photodynamic therapy for cancer

The therapeutic properties of light have been known for thousands of years, but it was only in the last century that photodynamic therapy (PDT) was developed. At present, PDT is being tested in the clinic for use in oncology--to treat cancers of the head and neck, brain, lung, pancreas, intraperitoneal cavity, breast, prostate and skin. How does PDT work, and how can it be used to treat cancer and other diseases?

PHOTOFRIN-mediated photodynamic therapy for treatment of early stage oral cavity and laryngeal malignancies

BACKGROUND AND OBJECTIVE

To determine the efficacy of PHOTOFRIN-mediated photodynamic therapy (PDT) for treatment of diffuse "field cancerization" of the oral cavity and Cis-T2N0M0 squamous cell carcinoma (SqCCa) of the larynx in patients not amenable or that have failed conventional head and neck treatment.

STUDY DESIGN/MATERIALS AND METHODS

Over the past 15 years 10 patients with early stage Tis-T2N0M0 SqCCa of the oral cavity and oropharynx and 10 patients with Tis-T2N0M0 SqCCa of the larynx were treated. Intravenous PHOTOFRIN (porfimer sodium) (dose 2.0 mg/kg) was administered outpatient, followed 48-60 hours later by intraoperative light photoactivation at 630 nm via fiberoptic microlens (ML) delivery (surgical light dose, 50-100 J/cm(2)) and/or cylindrical diffuser (CD) delivery (80-100 J/cm).

RESULTS

Complete responses (CRs) (follow up 6 months-9 years) were achieved in eight of 10 patients with diffuse field cancerization of the oral cavity. CRs (follow up 6 months-8 years) were achieved in eight of 10 patients with superficial laryngeal cancer obviating the need for total laryngectomy in previously treated radiation therapy patients.

CONCLUSION

PHOTOFRIN-mediated PDT provides a surgical oncologic modality for potentially curative treatment of early stage oral cavity and laryngeal malignancies with minimal side effects, absence of systemic toxicity, preservation of oral function and voice quality, with multiple drug administration, and laser light retreatment capability.

Photodynamic therapy in head and neck cancer

Photodynamic therapy is a nonsurgical, minimally invasive technique that uses a light source to activate light-sensitive drugs or photosensitizers to treat cancer and other diseases. The effect on living organisms caused by light in the presence of a photosensitizer and oxygen is known as the photodynamic effect or photodynamic action.

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.

Photodynamic therapy in dermatology

The combination of light and chemicals to treat skin diseases is widely practiced in dermatology. Within this broad use of light and drugs, in recent years the concept of photodynamic therapy (PDT) has emerged. PDT is a promising modality for the management of various tumors and nonmalignant diseases, based on the combination of a photosensitizer that is selectively localized in the target tissue and illumination of the lesion with visible light, resulting in photodamage and subsequent cell death. Moreover, the fluorescence of photosensitizing compounds is also utilized as a helpful diagnostic tool for the detection of neoplastic tissue. Intensive basic and clinical research culminated in the worldwide approval of PDT for bladder, esophageal, and lung cancer. The expanding use of this relatively new therapeutic modality in dermatology at many centers around the world has revealed its efficacy for the treatment of cutaneous precancer and cancer, as well as selected benign skin disorders. The following article summarizes the main principles of PDT considering the most recent developments and provides a comprehensive synopsis of the present status of the use of PDT in dermatology. (J Am Acad Dermatol 2000;42:389-413.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be able to describe the basic concepts of PDT, including fundamental knowledge of the most relevant photosensitizers, the light sources, the mechanisms involved in PDT-mediated cell destruction, as well as the indications and limitations of photodynamic treatment of skin diseases.

Photodynamic therapy

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Photodynamic therapy and the treatment of head and neck neoplasia

OBJECTIVE

To present the theory, technique, and results of photodynamic therapy for the treatment of oral, laryngeal, and head and neck cancers.

STUDY DESIGN

Retrospective review of the literature of more than 500 patients with head and neck cancer treated with photodynamic therapy, as well as a retrospective review of the author's 107 patients treated with photodynamic therapy for head and neck neoplasia between 1990 and 1997.

METHODS

The literature was retrospectively reviewed, as were patient records, and tabulated for age, sex, site, and staging of lesions, with special focus on post-photodynamic therapy treatment outcome, long-term disease-free survival, and complications.

RESULTS

Twenty-five patients with carcinoma in situ and T1 squamous cell carcinoma of the true vocal cord who underwent photodynamic therapy treatment for cure obtained a complete response after a single photodynamic therapy treatment. Only one patient has had recurrence to date, with a cure rate to 79-month follow-up of 95%. Twenty-nine patients with carcinoma in situ and T1 recurrent squamous cell carcinomas of the oral cavity and tongue were treated. All obtained a complete response after a single photodynamic therapy treatment; however, five patients developed local recurrence with follow-up to 70 months, for an 80% cure rate. A review of 217 patients with early squamous cell carcinomas of the head and neck treated with photodynamic therapy in the literature demonstrated an 89.5% complete response rate. The most common complication in these patients was limited prolonged skin photosensitivity without any permanent sequelae.

CONCLUSIONS

Photodynamic therapy is effective for treating carcinoma in situ and T1 squamous cell carcinoma of the larynx and oral cavity and may be of benefit as an adjuvant intraoperative treatment of stages III and IV tumors of the head and neck in conjunction with surgery and radiation therapy to improve cure rates. Further controlled studies need to be performed to further demonstrate the effectiveness of photodynamic therapy and the treatment of head and neck cancers.

Laser chemotherapy of human carcinoma cells with three new anticancer drugs

A new experimental therapy for squamous carcinoma was tested by sensitizing human tumor cells with light-sensitive anticancer drugs followed by laser illumination at visible or infrared wavelengths. The anthrapyrazole DUP-941 and the isoquinoline derivative DUP-840 were compared with the dianthraquinone hypericin. P3 human squamous carcinoma cells were incubated for 2 h with the drugs at escalating doses ranging from 5 to 100 micrograms/ml, then exposed to visible green 532-nm or infrared 1064-nm light at 300 J output from a KTP/Nd:YAG laser. Tumor cell toxicity measured by in vitro MTT viability assays was minimal after DUP-840 uptake but was slightly enhanced by infrared laser emissions. By contrast, the strong tumoricidal effects seen after DUP-941 uptake were amplified over 10-fold by 532-nm light and up to 2-fold by 1064-nm light. Hypericin-sensitized tumor cells were killed after 532 nm irradiation even at the lowest drug dose but were not affected by 1064-nm illumination. The results suggest that laser chemotherapy with drugs sensitive to photothermal energy could become a useful new treatment modality for cancer.

Photodynamic therapy in selected cases at the ENT Clinic, Innsbruck: case reports

Although photodynamic therapy (PDT) for the treatment of head and neck cancer has proved useful in other departments (J. Feyh, A. Goetz and W. Muller, Photodynamic therapy in head and neck surgery, J. Photochem. Photobiol. B: Biol., 7 (1990) 353-358; V.G. Schweitzer, Photodynamic therapy for treatment of head and neck cancer, Arch. Otolaryngol. Head Neck Surg., 102 (1990) 225-232; B.L. Wenig, D.M. Kurtzmann and L.I. Grossweiner, Photodynamic therapy in the treatment of squamous cell carcinomas of the head and neck, Arch. Otolaryngol. Head Neck Surg., 116 (1990) 1267-1270), it is not a standard therapy at the ENT Department of the University Clinic Innsbruck. PDT has only been applied in a few selected cases. Photosan 3 (dihaematoporphyrin either, DHE) was used as photosensitizer at a dose of 2.5 mg (kg body weight)-1 administered intravenously 24-48 h prior to photoirradiation. In one case, Photosan 3 was applied topically in a solution with 40% dimethylsulphoxide (DMSO). The light source was an argon dye laser with a wavelength of 630 nm and a power of 100 mW cm-2, coupled with a cylindrical or spherical applicator and a lens fibre tip. Patients suffering from cancer of the palatine arch, tonsil, nasal septum and glottis are reported. These selected cases had previous treatment (e.g. chemotherapy, percutaneous irradiation and surgery), and PDT was either performed as a palliative treatment for recurrence or in elderly patients to avoid inappropriate extensive and mutilating surgery.

Photodynamic therapy and the treatment of head and neck cancers

Photodynamic therapy is an effective curative treatment for early carcinomas of the head and neck and may be of benefit as an adjuvant intraoperative therapy to increase cure rates of large head and neck tumors. Eighty-seven patients with neoplastic diseases of the larynx, oral cavity, pharynx, and skin have been treated with photodynamic therapy (PDT) with follow-up to 66 months. Patients with carcinoma-in-situ and T1 carcinomas obtained a complete response after one PDT treatment. All but two have remained free of disease. Ten patients with massive neck recurrences of squamous cell carcinomas were treated with intraoperative adjuvant PDT following tumor resection. Only three developed recurrence with 40-month follow-up, but only one recurrence was in the field of surgery and PDT.

Effects of an erbium, chromium: yttrium, scandium, gallium, garnet laser on mucocutanous soft tissues

OBJECTIVES

Lasers are effective tools for soft tissue surgery. The erbium, chromium: yttrium, scandium, gallium, garnet laser is a new system that incorporates an air-water spray. This study evaluates the cutting margins of this laser and compares healing with laser and conventional scalpel and punch biopsy-induced wounds.

STUDY DESIGN

New Zealand white rabbits were divided into serial sacrifice groups; the tissues were grossly and microscopically analyzed after laser and convential steel surgical wounding.

RESULTS

Wound margins were found to show minimal edge coagulation artifact and were 20 to 40 mm in width. Laser wounds showed minimal to no hemorrhage and re-epithelialization and collagenization were found to occur by day 7 in both laser and conventional groups.

CONCLUSIONS

The new laser system is an effective soft tissue surgical device; wound healing is comparable to that associated with surgical steel wounds. The minimal edge artifact observed with this laser system should allow for the procurement of diagnostic biopsy specimens.

Photodynamic therapy of oral cancer. A review of basic mechanisms and clinical applications

Photodynamic therapy (PDT) is an experimental cancer treatment modality. PDT is based on the accumulation of a photosensitive dye in premalignant and malignant lesions. A certain period of time after the dye has been administered, tumor tissue may contain more of the sensitizer then the surrounding normal tissues. When tissue containing the sensitizer is exposed to light of a proper wavelength and dose, a photochemical reaction between sensitizer and light will occur. The activated photosensitizer reacts with available oxygen which subsequently damages cells and eventually may cause necrosis of the tumor. Photosensitizers can also be used for fluorescence detection. If a tumor contains more of the photosensitizer than the surrounding normal tissue, its fluorescence can potentially be utilized to detect tumors. Analogous to PDT, this can therefore be referred to as photodynamic detection (PDD). This paper reviews the basic mechanisms and clinical applications of PDT and PDD. Emphasis is placed on PDD and PDT with the photosensitizer Photofrin for detection and treatment of premalignant epithelial lesions and squamous cell carcinomas of the oral mucosa.

Laser photochemotherapy with anthracyclines on cultured human squamous carcinoma cells

A new treatment for cancer has been tested in vitro using light-sensitive anthracyclines followed by laser photoactivation, as described by several investigators. We previously reported 10-fold enhanced laser killing after 2 hours of incubation with daunomycin by cultured human carcinoma cells. This short-term uptake leads to drug localization in cytoplasmic and membrane sites prior to nuclear accumulation and topoisomerase inhibition. In the present study, daunomycin was incubated for 2 or 24 hours with P3 squamous carcinoma cells to directly compare cytoplasmic vs. nuclear drug targeting before and after KTP-532 laser activation. Monolayer cultures of the P3 cells sensitized with daunomycin for 2 hours, then chilled (4 degree C), and exposed to the KTP laser (532 nm, 94.2 J/cm2) had a 2- to 10-fold increased therapeutic response compared with drug or laser alone when measured by MTT tetrazolium assays. After 24 hours of incubation with daunomycin, the chemotherapeutic response of P3 tumor cells was amplified 2-fold by laser exposure. The results suggest that daunomycin and laser treatment can be combined for improved therapy of human cancer.

Interstitial laser photochemotherapy with new anthrapyrazole drugs for the treatment of xenograft tumors

Photodynamic therapy (PDT) with lasers and new dyes has gained popularity in recent years as a minimally invasive technique with high tumoricidal effects in vitro and in some cancer patients. However, because new laser dyes are not FDA approved at present, the clinical evaluation of PDT may be years away. During the past 6 years we have used laser alone for photothermal ablation in both preclinical studies and in a large number of patients with an observed 60% tumor response rate. The 40% treatment failure led us to explore the possibility of combined therapy with lasers and standard chemotherapeutic drugs. We have recently tested a promising preclinical alternative using implantation of a bare 600-microns KTP 532 laser fiberoptic in multiple tumor sites 30 min after intratumor injection of the anthrapyrazole DUP-941. As a control, this drug was injected in 3 sites of P3 human squamous cell tumor transplants in nude mice, which led to tumor stasis without regression. Similar 400-600 mm3 tumors exposed to laser illumination alone (0.8 W for 5 sec) at multiple sites resulted in tumor regrowth after 10 weeks in 80% of the animals. However, combining interstitial laser illumination with intratumor DUP-941 injections led to complete tumor regression in 85% of the mice. We propose that intratumor drug injection followed by interstitial laser fiberoptic treatment represents a potentially useful new method for tumor ablation in advanced cancer patients.

Photodynamic therapy of head and neck cancers

Sixty-five patients with neoplastic diseases of the larynx, oral cavity, pharynx, and skin have been treated with photodynamic therapy (PDT) with follow-up to 56 months. Patients with carcinoma in situ (CIS) and T1 carcinomas obtained a complete response after one PDT treatment. All but two have remained free of disease. Eight patients with T2 and T3 carcinomas treated with PDT obtained a complete response, but they all recurred locally. This is due to the inability to adequately deliver laser light to the depths of the tumor bed. Five patients with massive neck recurrences of squamous cell carcinomas were treated with intraoperative adjuvant PDT following tumor resection. Only one developed recurrence with 24-month follow-up. PDT is highly effective for the curative treatment of early carcinomas (CIS, T1) of the head and neck. Also, intraoperative adjuvant PDT may increase cure rates of large infiltrating carcinomas of the head and neck.

Photodynamic therapy for obstructing esophageal cancer: light dosimetry and randomized comparison with Nd:YAG laser therapy

BACKGROUND & AIMS

Light dosimetry analysis to achieve predictable tumor necrosis has not been performed for photodynamic therapy (PDT) in the gastrointestinal tract. We evaluated dihematoporphyrin ethers for sensitizing esophageal carcinomas to 630 nm light and compared PDT with neodymium:yttrium-aluminum-garnet (Nd:YAG) laser therapy in a randomized trial.

METHODS

Of 52 patients with dysphagia, 32 received palliative PDT. Ten patients treated with PDT participated in a preliminary trial using various doses of 630-nm light, and 22 patients treated with PDT participated in a randomized trial using a derived standardized light dose for comparison with 20 patients treated with the Nd:YAG laser.

RESULTS

Light dosimetry correlated with depth of tumor necrosis (r = 0.664; P < 0.001). PDT activity was similar for squamous cell and adenocarcinoma. Among randomized patients, both PDT and Nd:YAG therapy relieved dysphagia, but PDT resulted in improved Karnofsky performance status at 1 month (+7 vs. -7; P < 0.001) and longer duration of response (84 vs. 57 days; P = 0.008). Skin photoreactions were unique to PDT.

CONCLUSIONS

The extent of PDT tumor ablation correlates with light dosimetry, enabling selection of a standardized light dose. PDT can relieve esophageal obstruction from squamous cell and adenocarcinoma and is an alternative to Nd:YAG thermal necrosis with a longer duration of response. However, PDT requires patient precautions to minimize skin photoreactions.