Adjuvant Intraoperative Photodynamic Therapy Research Articles

Adjuvant Intraoperative Photodynamic Therapy in Head and Neck Cancer

There is an immediate need to develop local intraoperative adjuvant treatment strategies to improve outcomes in patients with cancer who undergo head and neck surgery. To determine the safety of photodynamic therapy with 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH) in combination with surgery in patients with head and neck squamous cell carcinoma. Nonrandomized, single-arm, single-site, phase 1 study at a comprehensive cancer center among 16 adult patients (median age, 65 years) with biopsy-proved primary or recurrent resectable head and neck squamous cell carcinoma. Intravenous injection of HPPH (4.0 mg/m2), followed by activation with 665-nm laser light in the surgical bed immediately after tumor resection. Adverse events and highest laser light dose. Fifteen patients received the full course of treatment, and 1 patient received HPPH without intraoperative laser light because of an unrelated myocardial infarction. Disease sites included larynx (7 patients), oral cavity (6 patients), skin (1 patient), ear canal (1 patient), and oropharynx (1 patient, who received HPPH only). The most frequent adverse events related to photodynamic therapy were mild to moderate edema (9 patients) and pain (3 patients). One patient developed a grade 3 fistula after salvage laryngectomy, and another patient developed a grade 3 wound infection and mandibular fracture. Phototoxicity reactions included 1 moderate photophobia and 2 mild to moderate skin burns (2 due to operating room spotlights and 1 due to the pulse oximeter). The highest laser light dose was 75 J/cm2. The adjuvant use of HPPH-photodynamic therapy and surgery for head and neck squamous cell carcinoma seems safe and deserves further study. clinicaltrials.gov Identifier: NCT00470496.

Efficacy of the adjuvant intraoperative photodynamic therapy with Photolon ® in patients with malignant brain tumors

Efficacy of the adjuvant intraoperative photodynamic therapy with Photolon ® in patients with malignant brain tumors

Adjuvant intraoperative photodynamic therapy in experimental colorectal cancer.

A reliable animal model for quantitative assessment of local recurrence of colorectal cancer was developed using colo26 tumour in BALB/c mice. The effect of adjuvant intraoperative photodynamic therapy to potentially curative surgery on local recurrence was examined in four study and four control groups. Study groups received 15 mg kg-1 Photofrin (a photosensitizing drug) 24 h before surgery. After 'curative' tumour excision, the tumour beds were illuminated with either 630 nm or 510 nm laser light each at 40 and 70 J/cm-2. Controls received surgery only, surgery and Photofrin only or surgery and either 630 nm or 510 nm light. The local recurrence rates at 70 days were 17-33 per cent in the study groups compared with 83-100 per cent in the control groups (P < 0.001; log rank test). Photodynamic therapy is capable of reducing local recurrence following potentially curative excision of tumour in this model.

Adjuvant intraoperative photodynamic therapy in experimental colorectal cancer using a new photosensitizer

Photodynamic therapy is a promising anticancer modality. The effect of adjuvant intraoperative photodynamic therapy (AIOPDT) using photosensitizers Photofrin or mesotetra (hydroxyphenyl) chlorin (m-THPC) was evaluated in a mouse model of local recurrence of colorectal cancer. Animals were injected with either photosensitizer 24 h before surgery. Standard excision included removal of all visible tumour by a surgeon blinded to both the drug and subsequent light treatment. Following surgery the tumour beds were illuminated with either 70 J cm-2 of 510-nm light (Photofrin) or 2.5 J cm-2 of 652-nm light (m-THPC). Control groups had either surgery only, surgery and Photofrin only, surgery and m-THPC only, or surgery and either 652-nm or 510-nm light. After a 70-day observation period, the local recurrence rates were 25-26 per cent in the photodynamic therapy groups compared with 80-90 per cent in the control groups (P < 0.001). AIOPDT using either Photofrin or m-THPC was equally effective in reducing local recurrence in this model. Since treatment time with m-THPC was only 25 s compared with 11 min with Photofrin, the use of the former new photosensitizer increases the practicality of AIOPDT and could enable the laser to be replaced with cheaper, less intense light sources.

Adjuvant intraoperative photodynamic therapy in experimental colorectal cancer using a new photosensitizer

Adjuvant intraoperative photodynamic therapy in experimental colorectal cancer using a new photosensitizer

Current status of photodynamic therapy in oncology.

Photodynamic therapy (PDT) is a cancer treatment based on the accumulation in malignant tissue of a photosensitiser with low systemic toxicity. Subsequent illumination induces a type II photochemical reaction with singlet oxygen production that results in destruction of biomolecules and subcellular organelles. The first full clinical report of PDT dates from 1976. Haematoporphyrin derivative, a complex mixture of porphyrins, was initially used as a photosensitiser. An enriched fraction (porfimer sodium) is now the most commonly used clinical agent. After systemic administration porphyrins bind to albumin and lipoproteins. Accumulation occurs mainly in tumours and organs of the reticuloendothelial system. The light of an argon-dye laser can be tuned to the appropriate wavelength and delivered either superficially, interstitially or intraluminally. Light distribution can be assessed by using a radiation transport model and tissue optical properties, or direct measurement with light detectors. The effects of PDT depend in a complex way on: characteristics, tissue concentration and localisation of the photosensitiser; the target tissue optical properties and oxygenation; activation wavelength, power density and treatment regimen. Future research is directed towards: better photosensitisers (i.e. phthalocyanines, chlorins or protoporphyrin IX endogenously produced from 5-aminolevulinic acid); improved light generation and delivery; and combination with hyperthermia, chemotherapy, radiotherapy or surgery. Adjuvant intraoperative PDT is a promising approach to destroying residual tumour after surgery.

Adjuvant intraoperative photodynamic therapy for colorectal carcinoma: a clinical study

The local recurrence rate of colorectal carcinoma after surgery is unacceptable in most series, and adjuvant therapies have made only a small impact on this. There is experimental evidence that adjuvant intraoperative photodynamic therapy (AIOPDT) may be effective. AIOPDT involves systemically photosensitizing the patient preoperatively with a drug (HpD) which relatively localizes to tumour and is activated using visible light. At operation the resected tumour bed is illuminated with a predetermined uniform light energy density to eradicate microscopic tumour deposits left at the lateral resection margin. We have previously investigated technical and biological factors leading to this clinical trial. Seventeen patients have received AIOPDT in a potentially effective dose, and safety and technical matters have been investigated. Cutaneous phototoxicity occurred in 3 patients. Three patients had anastomotic breakdown, none considered attributable to PDT. The intraoperative technique was a practical option. AIOPDT carried a low patient morbidity and should be investigated in prospective clinical trials to determine if local recurrence rates can be decreased.