5-aminolevulinic-acid-hexyl-ester and Peritoneal-Neoplasms

While photodynamic therapy (PDT) is a promising treatment for peritoneal carcinomatosis, its use is often limited because of the toxicity of photosensitizers. In this study, safety of PDT with hexaminoevulinate (HAL), a second generation photosensitizer, is assessed.. PDT of the peritoneal cavity was performed in a rat model of peritoneal carcinomatosis. Rats were treated according to different protocols: with full or half HAL dose, after intraperitoneal or oral administration of HAL, 4 or 8h after its injection, using red or green light, after protection of the liver or cooling of the abdominal wall. Toxicity was assessed by blood tests quantifying hematocrit, liver and muscular enzymes and by pathological examination of abdominal and intrathoracic organs after treatment. The results were analyzed in the light of quantification of fluorescence and protoporphyrin IX (PPIX) content of the same organs.. PDT with HAL induced rhabdomyolysis, intestinal necrosis and liver function test anomalies, leading to death in 2 out of 34 rats. The liver and the intestine contained high levels of PPIX (3-5 times more than tumor nodules).. HAL PDT lacked specificity. However, the strategy associating diagnosis, treatment and evaluation of the results in one single procedure was effective and should be tested with other photosensitizers.

Topics: Aminolevulinic Acid; Animals; Cell Line, Tumor; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Female; Infusions, Parenteral; Intestinal Diseases; Ovarian Neoplasms; Peritoneal Neoplasms; Photochemotherapy; Photosensitizing Agents; Rats; Rats, Inbred F344; Rhabdomyolysis; Treatment Outcome

A homogeneous illumination of intra-abdominal organs is essential for successful photodynamic therapy of the abdominal cavity. Considering the current lack of outstanding light-delivery systems, a new illumination procedure was assessed. A rat model of peritoneal carcinomatosis was used. Four hours after intraperitoneal injection of hexaminolevulinate, a square illuminating panel connected to a 635-nm laser source was inserted vertically into the abdominal cavity. The abdominal incision was sutured and a pneumoperitoneum created prior to illumination. Light dosimetry was based on the calculation of the peritoneal surface by MRI. The rats were treated with a light dose of 20, 10, 5 or 2.5 J/cm(2) administered continuously with an irradiance of 7 mW/cm(2). The homogeneity of the cavity illumination was assessed by quantification of the photobleaching of the tumor lesions according to their localization and by scoring of that of the liver and of the bowel immediately after treatment. Photobleaching quantification for tumor lesions relied on the calculation of the fluorescence intensity ratio (after/before treatment) after recording of the lesions during blue-light laparoscopy and determination of their fluorescence intensity with Sigmascan Pro software. The procedure led to a homogeneous treatment of the abdominal cavity. No statistical difference was observed for the photobleaching values according to the localization of the lesions on the peritoneum (p=0.59) and photobleaching of the liver and of the intestine was homogeneous. We conclude that this procedure can successfully treat the major sites involved in peritoneal carcinomatosis.

Topics: Abdominal Cavity; Adenocarcinoma; Aminolevulinic Acid; Animals; Cell Line, Tumor; Female; Intestines; Liver; Magnetic Resonance Imaging; Ovarian Neoplasms; Peritoneal Neoplasms; Photochemotherapy; Photosensitizing Agents; Radiometry; Rats; Rats, Inbred F344; Spectrometry, Fluorescence; Statistics, Nonparametric

This experimental study aimed to compare three illumination schemes to optimize hexaminolaevulinate (HAL)-PDT in a rat tumor model with advanced ovarian cancer.. Peritoneal carcinomatosis was induced by intraperitoneal 5×10(6)NuTu-19 cells injection in 60 female rats Fisher 344. Carcinomatosis was obtained 50 days post-tumor induction. Four hours post-intraperitoneal HAL (Photocure ASA, Oslo, Norway) injection, three different schemes of PDT were performed during 25 min on a 1cm(2) area. (A) Fractionated illumination (n=20) with an on-off cycle ("on": 2 min and "off": 1 min) at 30mW cm(-2) until a fluence of 30J cm(-2), (B) continuous illumination (n=20) at 30mW cm(-2) with a fluence of (45J cm(-2)C) continuous illumination (n=20) at 20mW cm(-2) with a fluence of 30J cm(-2). Laser light was generated using a 532nm KTP laser (Laser Quantum, Stockport, UK). Biopsies were taken 24h after treatment. Quantitative histology was performed. Necrosis value was determined: 0-no necrosis to 4-full necrosis. Depth of necrosis was then measured for each sample and correlated to Necrosis value.. HAL-PDT was efficient in producing necrosis irrespective of the scheme. Tumor destruction was superior with fractionated illumination compared to both continuous illumination schemes regarding to the depth of necrosis (213±113μm vs 154±133μm vs 171±155μm) (p<0.05) or to the full necrosis rate (50% vs 30% vs 10%) (p<0.0001).. Fractionated illumination during photodynamic therapy (PDT) was shown to improve tumor response. Fractionated illumination with short intervals should be considered for an effective PDT of advanced ovarian cancer.

Topics: Adenocarcinoma; Aminolevulinic Acid; Animals; Disease Models, Animal; Female; Ovarian Neoplasms; Peritoneal Neoplasms; Photochemotherapy; Photosensitizing Agents; Rats; Rats, Inbred F344