| Popis: |
Pre-cancerous lesions and mucosally confined superficial cancers can benefit from local therapy given with curative intent due to the absence of near metastatic lymph nodes. Photodynamic therapy (PDT) which acts by laser irradiation with an appropriate wave-length after administration of a photosensitiser retained preferentially by the cancerous tissue can destroy tumour cells selectively, but its efficiency depends upon the photosensitiser. The results presented concern 10 sites on Barrett's mucosa (BO). They consisted of either an association of intramucosal cancer (IMC) with high-grade dysplasia (HGD) or of high-grade dysplasia alone. The method consisted of intravenous injection of Temoporfin 0,15 mg/kg 4 days before irradiation of the lesion with a green laser light emitting 514 nm through a windowed diffuser. The light fluence was 75 J per cm2 and irradiation 100 mW per cm2. Irradiation time was 12,5 mn. Omeprazole was routinely prescribed after treatment at a dose of 40 mg daily. The follow-up protocol was 2 years with endoscopic surveillance at 2, 3, 6, 12, 18 and 24 months. Biopsies obligatory at 2 and 3 months were in fact carried out at all the other delays. Efficacy was judged on the absence of high-grade dysplasia or intra mucosal carcinoma on biopsies at treated sites. Undesirable side effects noted have been moderate for the most part. No stenosis appeared. Treatment has been 100% successful for the 10 lesion after 15 treatments with PDT. The follow up varies from 6-36 months and was more than 18 months for 6 lesions on 5 patients. Our series has demonstrated a great heterogeneity in lesions which were sometimes visible and highly localised, but more often invisible, multi-focal and diagnosable only by biopsy at different levels. In keeping with the literature and our experience, PDT has several advantages over the other locally curative therapies, mucosectomy and thermocoagulation. These are the possible treatments without general anaesthesia, selectively for cancer cells, an action on more extensive areas with eradication of non visible lesions. Temoporfin has contributed notably to the field of photodynamic therapy compared to previously used sensitisers. It is a pure, synthetic product which guarantees more reproducible results. Compared with Photofrin, Temoporfin has many advantages with smaller doses of drugs and less energy, better selectivity and rapid elimination which reduce the risk period for photosensitisation. The frequency of important undesirable side effects is diminished. Finally, it produces a consistent effect on the surface and in depth producing a complete reepithelialisation of the treated zones. Subject to validation of the method on a greater number of patients, the first results obtained on superficial cancer in Barrett's aesophagus allow us to propose green light Temoporfin PDT as an alternative first line therapy with curative intent. |
