Local curative treatment of superficial adenocarcinoma in Barrett's oesophagus. First results of photodynamic therapy using a new photosensitizer

Pre-cancerous lesions and mucosally confined superficial cancers can benefi t from local therapy given with curative intent due to the absence of near metastatic lymph nodes. Photodynamic therapy (PDT) which acts by laser irra diation with an appropriate wavelength after administration of a photosensi tiser retained preferentially by the cancerous tissue can destroy tumour ce lls selectively, but its efficiency depends upon the photosensitiser. The r esults presented concern 10 sites on Barrett's mucosa(BO). They consisted o f either an association of intramucosal cancer(IMC) with high-grade dysplas ia(HGD) or of high-grade dysplasia alone. The method consisted of intraveno us injection of Temoporfin 0,15 mg/kg 4 days before irradiation of the lesi on with a green laser light emitting 514 nm through a windowed diffuser. Th e light fluence was 75 J per cm(2) and irradiation 100 mW per cm(2). Irradi ation 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 endoscop ic 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 moderat e for the most part. No stenosis appeared. Treatment has been 100 % success ful for the 10 lesions after 15 treatments with PDT. The follow up varies f rom 6-36 months and was more than 18 months for 6 lesions on 5 patients. Ou r series has demonstrated a great heterogeneity in lesions which were somet imes visible and highly localised, but more often invisible, multi-focal an d diagnosable only by biopsy at different levels In keeping with the litera ture and our experience PDT has several advantages over the other locally c urative therapies, mucosectomy and thermocoagulation. These are the possibl e treatments without general anaesthesia, selectivity for cancer cells, an action on more extensive areas with eradication of non visible lesions. Tem oporfin has contributed notably to the field of photodynamic therapy compar ed to previously used sensitisers. It is a pure, synthetic product which gu arantees more reproducible results. Compared with Photofrin (R), Temoporfin has many advantages with smaller doses of drugs and less energy better sel ectivity and rapid elimination which reduce the risk period for photosensit isation. The frequency of important undesirable side effects is diminished. Finally, it produces a consistent effect on the surface and in depth produ cing a complete reepithelialisation of the treated zones. Subject to valida tion of the method on a greater number of patients the first results obtain ed on superficial cancer in Barrett's oesophagus allow us to propose green light Temoporfin PDT as an alternative first line therapy with curative int ent.