Photodynamic Therapy in the Treatment of Cancer: A review (original) (raw)

Photodynamic therapy of cancer: An update

CA: A Cancer Journal for Clinicians, 2011

Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic procedure that can exert a selective cytotoxic activity toward malignant cells. The procedure involves administration of a photosensitizing agent followed by irradiation at a wavelength corresponding to an absorbance band of the sensitizer. In the presence of oxygen, a series of events lead to direct tumor cell death, damage to the microvasculature, and induction of a local inflammatory reaction. Clinical studies revealed that PDT can be curative, particularly in early stage tumors. It can prolong survival in patients with inoperable cancers and significantly improve quality of life. Minimal normal tissue toxicity, negligible systemic effects, greatly reduced long-term morbidity, lack of intrinsic or acquired resistance mechanisms, and excellent cosmetic as well as organ function-sparing effects of this treatment make it a valuable therapeutic option for combination treatments. With a number of recent technological improvements, PDT has the potential to become integrated into the mainstream of cancer treatment. CA Cancer J Clin 2011;61:250-281

Photodynamic therapy of cancer. Basic principles and applications

Clinical & Translational Oncology, 2008

Photodynamic therapy (PDT) is a minimally invasive therapeutic modality approved for clinical treatment of several types of cancer and non-oncological disorders. In PDT, a compound with photosensitising properties (photosensitiser, PS) is selectively accumulated in malignant tissues. The subsequent activation of the PS by visible light, preferentially in the red region of the visible spectrum (λ≥600 nm), where tissues are more permeable to light, generates reactive oxygen species, mainly singlet oxygen (1O2), responsible for cytotoxicity of neoplastic cells and tumour regression. There are three main mechanisms described by which 1O2 contributes to the destruction of tumours by PDT: direct cellular damage, vascular shutdown and activation of immune response against tumour cells. The advantages of PDT over other conventional cancer treatments are its low systemic toxicity and its ability to selectively destroy tumours accessible to light. Therefore, PDT is being used for the treatment of endoscopically accessible tumours such as lung, bladder, gastrointestinal and gynaecological neoplasms, and also in dermatology for the treatment of non-melanoma skin cancers (basal cell carcinoma) and precancerous diseases (actinic keratosis). Photofrin®, ALA and its ester derivatives are the main compounds used in clinical trials, though newer and more efficient PSs are being evaluated nowadays.

Photodynamic therapy in cancer treatment -an update review

Journal of Cancer Metastasis and Treatment , 2019

Cancer remains a worldwide health problem, being the disease with the highest impact on global health. Even with all the recent technological improvements, recurrence and metastasis still are the main cause of death. Since photodynamic therapy (PDT) does not compromise other treatment options and presents reduced long-term morbidity when compared with chemotherapy or radiotherapy, it appears as a promising alternative treatment for controlling malignant diseases. In this review, we set out to perform a broad update on PDT in cancer research and treatment, discussing how this approach has been applied and what it could add to breast cancer therapy. We covered topics going from the photochemical mechanisms involved, the different cell death mechanisms being triggered by a myriad of photosensitizers up to the more recent-ongoing clinical trials.

Photodynamic Therapy (PDT) in Oncology

Cancers

The issue is focused on Photodynamic Therapy (PDT), which is a minimally invasive therapeutic modality approved for treatment of several types of cancer and non-oncological disorders [...]

Photodynamic therapy--indications and limits in malignant tumors treatment

Romanian journal of internal medicine = Revue roumaine de médecine interne, 2008

Photodynamic therapy (PDT) is a very promising technique used for the treatment of a variety of solid neoplasms, based on the formation of singlet oxygen induced by a photosensitizer after irradiation with visible light. The mechanism of interaction of the photosensitizers and light is discussed, along with the effects produced in the target tissue. PDT has been approved in many countries for the treatment of lung, esophageal, bladder, skin and head and neck cancers. The antitumor effects of this treatment result from the combination of direct tumor cell photodamage, destruction of tumor vasculature and activation of an immune response. The present status of clinical PDT is discussed along with the newer photosensitizers being used and their clinical roles. Despite the promising results from earlier clinical trials of PDT considerable additional work is needed to bring this new modality of treatment into modern clinical practice.

Direct tumor damage mechanisms of photodynamic therapy

Acta biochimica Polonica, 2005

Photodynamic therapy (PDT) is a clinically approved and rapidly developing cancer treatment regimen. It is a minimally invasive two-stage procedure that requires administration of a photosensitizing agent followed by illumination of the tumor with visible light usually generated by laser sources. A third component of PDT is molecular oxygen which is required for the most effective antitumor effects. In the presence of the latter, light of an appropriate wavelength excites the photosensitizer thereby producing cytotoxic intermediates that damage cellular structures. PDT has been approved in many countries for the treatment of lung, esophageal, bladder, skin and head and neck cancers. The antitumor effects of this treatment result from the combination of direct tumor cell photodamage, destruction of tumor vasculature and activation of an immune response. The mechanisms of the direct photodamage of tumor cells, the signaling pathways that lead to apoptosis or survival of sublethaly dam...

Approaches to improve photodynamic therapy of cancer

2011

Introduction 3. Major advantages and disadvantages of PDT-what needs improvement or might be improved? 4. New photosensitizers 5. New light sources 6. Targeting cytoprotective mechanisms in PDT-treated cells 6.1. ROS-scavenging enzymes 6.2. Handling of damaged proteins 6.3. Mechanisms not directly associated with ROS scavenging 7. Combinations of PDT with other treatment modalities 8. Enhancement of PDT-mediated immune response 8.1. Immunoadjuvants 8.2. Cytokines 8.3. Adoptive immunotherapy 8.4. Introduction of foreign antigens 8.5. Anticancer therapeutics 9. Other new directions 9.1. Photochemical internalization 9.2. Metronomic PDT 9.3. Nanoparticle-based PDT 9.4. Two photon PDT 10. Conclusions 11. Acknowledgments 12. References Photodynamic therapy of cancer nanovehicle preparation for photodynamic therapy in vitro.

Cell Death Pathways Associated with Photodynamic Therapy: An Update

Photochemistry and photobiology, 2018

Photodynamic therapy (PDT) has the potential to make a significant impact on cancer treatment. PDT can sensitize malignant tissues to light, leading to a highly selective effect if an appropriate light dose can be delivered. Variations in light distribution and drug delivery, along with impaired efficacy in hypoxic regions, can reduce the overall tumor response. There is also evidence that malignant cells surviving PDT may become more aggressive than the initial tumor population. Promotion of more effective direct tumor eradication is therefore an important goal. While a list of properties for the "ideal" photosensitizing agent often includes formulation, pharmacologic and photophysical elements, we propose that subcellular targeting is also an important consideration. Perspectives relating to optimizing PDT efficacy are offered here. These relate to death pathways initiated by photodamage to particular subcellular organelles.

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

Cancers

Current research to find effective anticancer treatments is being performed on photodynamic therapy (PDT) with increasing attention. PDT is a very promising therapeutic way to combine a photosensitive drug with visible light to manage different intense malignancies. PDT has several benefits, including better safety and lower toxicity in the treatment of malignant tumors over traditional cancer therapy. This reasonably simple approach utilizes three integral elements: a photosensitizer (PS), a source of light, and oxygen. Upon light irradiation of a particular wavelength, the PS generates reactive oxygen species (ROS), beginning a cascade of cellular death transformations. The positive therapeutic impact of PDT may be limited because several factors of this therapy include low solubilities of PSs, restricting their effective administration, blood circulation, and poor tumor specificity. Therefore, utilizing nanocarrier systems that modulate PS pharmacokinetics (PK) and pharmacodynami...