Biodegradable polydioxanone stents: a new option for therapy-resistant anastomotic strictures of the colon.

OBJECTIVES: To assess the outcome of self-expandable, biodegradable stent insertion for anastomotic strictures following treatment for rectosigmoid carcinoma. METHODS: Three male patients (median age 66) developed benign strictures after radiotherapy and resection of a recto-sigmoid carcinoma. These were resistant to balloon dilatation and prevented stoma reversal. Biodegradable stent insertion was performed as an experimental treatment on a named-patient basis with approval of the institutional review board. Patients had monthly follow-up with endoscopy and contrast medium enemas to monitor performance and degradation of the stents. RESULTS: All stents were placed successfully without complications after pre-dilatation to 20 mm under fluoroscopic guidance. Stent degradation occurred in all patients 4-5 months following implantation, and long-term anastomotic patency was demonstrated in all. This allowed reversal of the colostomy and physiological defecation in two patients. Reversal was not undertaken in one due to subsequent development of liver metastases. No stent migration or occlusion occurred. CONCLUSIONS: Biodegradable stents can maintain an adequate lumen across anastomotic strictures resistant to balloon dilatation. They seem to allow stricture re-modelling resulting in maintained dilatation after degradation. This potentially allows reversal of a colostomy, which might otherwise be prevented by stricture recurrence.

Peroperative optical autofluorescence biopsy--verification of its diagnostic potential.

The authors tested the diagnostic potential of the portable autofluorescence optical system that was developed in the preoperative evaluation of resection margins, and thus of the resection line safety in patients with low-positioned colorectal carcinoma. A total of 217 spectral measurements of the fluorescence properties of normal (117) and malignant (100) tissues in 19 patients with colorectal carcinoma were accomplished. The measured spectra thus acquired were then evaluated using logistic regression. Using the principal component method, the authors selected the 30 and 40 most significant wavelengths, respectively, which they then used to construct the logistic model. The model met the basic criteria of statistical significance. The classification power of the model was 79.7% (for 30 wavelengths) and 82.5% (for 40). Statistical discrimination was 0.88 and 0.91, respectively. These results confirm that the optical setup that we selected is suitable for the peroperative testing of the distal resection line. It is capable of differentiating with 90% confidence pathological tissue and thus of reliably guiding further histological processing.

Evaluation of topical photodynamic therapy of mammary carcinoma with an experimental gel containing liposomal hydroxyl-aluminium phthalocyanine.

BACKGROUND: Photodynamic therapy (PDT) is a clinically-accepted approach for the therapy of many types of cancer. This study focused on the treatment of mammarian carcinoma by topical administration of hydroxyl-aluminium phthalocyanine (AlOH-PC), compared to a clinically-approved photosensitizer (Metvix, Galderma & PhotoCure ASA, Inc., Oslo, Norway). MATERIALS AND METHODS: MDA-MB 231 cells were subcutaneously injected into the right flank of athymic nude mice. Mice with grown tumours were used for in vivo efficacy studies. Different doses of liposomal AlOH-PC were applied to determine the most effective dose. In later studies, Metvix or our liposomal-AlOH-PC gel formula were used. Topical application of photosensitizers was followed by the PDT irradiation at 600-700 nm (635 nm peak). Tumour growth was measured three times weekly. RESULTS: Therapeutic studies revealed that AlOH-PC treatment led to complete tumour remission in 90% (9/10) of experimental animals, whereas usage of the commercially available Metvix only postponed the tumour growth. Moreover, usage of liposomal AlOH-PC shortened the time allowed between the application of the photosensitizer and light exposure: for Metvix, hours are usually needed, while the tested liposomal AlOH-PC showed remarkable outcomes after only 10 min. CONCLUSION: Liposomal AlOH-PC gel appears to be potentially suitable for PDT of mammarian carcinoma.

Photodynamic therapy of human colorectal carcinoma cell line.

Colorectal cancer is one of the most common cancers in Europe and North America and it is the most common gastrointestinal carcinoma. The population in the Czech Republic has a higher incidence of colorectal carcinoma compared to other countries. Efforts are underway to develop better screening strategies and novel therapies to improve patient survival rates. Despite all efforts, colorectal cancer remains one of the leading causes of death from cancer. Photodynamic therapy (PDT) is an established modality for the treatment of various diseases. The PDT procedure involves the administration of a photosensitizer followed by illumination. The anti-tumor effects result from direct killing of malignant cells, shutting down of the tumor's vasculature, and the promotion of an immune response. In our experiment, we examined the effects of phototherapy with disulfonated hydroxyaluminum phthalocyanine (Al(OH)S2Pc) on the growth of colorectal carcinoma cells, in an effort to offer a new treatment modality for patients with this disease.