Photodynamic therapy of cancer: An update

Abstract

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 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.

Synergic effect of photodynamic therapy using talaporfin sodium with conventional anticancer chemotherapy for the treatment of bile duct carcinoma

“…1 PDT is technically feasible and is a useful modality for treating non-resectable or resectable bile duct carcinomas (BDC). [2][3][4][5] Remarkably, PDT treatment induces a powerful anti-tumor immunological response.…”

“…9 The first clinically approved photosensitizer, porfimer sodium (Photofrin ® ), is a hematoporphyrin derivative and has a very powerful cytocidal effect in BDC. [1][2][3][4][5][6][7][8] However, the anti-tumor effect was limited to the shallow bile duct wall because the 630 nm laser used in treatment had a low permeability. 10 Furthermore, the long period of skin photosensitivity required the patients to be kept away from strong sunlight for several weeks following the drug administration.…”

A Tumor Vascular‐Targeted Interlocking Trimodal Nanosystem That Induces and Exploits Hypoxia

“…This observation indicated that siHIF‐1α delivered by the nanosystem can exert its function (HIF‐1α suppression) in a wider tumor region. Furthermore, VTP‐induced exacerbated hypoxia in the region distant from the vessels can directly kill the tumor cells and lead to tumor regression, which is the major rationale for VTP to treat solid tumors in clinic 2, 45. The histopathological examination also demonstrated that the targeted trimodal nanosystem resulted in widespread apoptosis in the tumors (Figure S13, Supporting Information).…”

“…VP‐mediated PDT has been approved for age‐related macular degeneration,2 and also investigated against multiple cancers 12…”

Resistência de células de carcinoma epidermóide bucal à terapia fotodinâmica mediada pelo ácido 5-aminolevulínico

“…A ação intensa de espécies reativas de oxigênio provoca a morte celular direta, tanto por apoptose quanto por necrose ou autofagia, levando à destruição do tumor. As células tumorais podem também exibir danos irreversíveis derivados de isquemia originária de alterações vasculares pós-PDT, bem como serem destruídas pelo sistema imune, por intermédio de reações antitumorais específicas acionadas também após essa terapia (Agostinis et al, 2011). Uma das vantagens da PDT para o CEC bucal consiste na possibilidade de se associar essa terapia com a cirurgia, levando à diminuição do tumor e tornando-o ressecável (Biel, 2010).…”