Endoscopic Ablation of Barrett's Esophagus: A Randomized Trial of Photodynamic Therapy (PDT) Versus Argon Plasma Coagulation (APC)

Abstract

Background: Barrett's esophagus (BE) is the major risk factor for adenocarcinoma of the esophagus, which is increasing in incidence more rapidly than any other cancer in the Western World. BE confers a lifetime risk for developing adenocarcinoma of 10-15%. Both PDT using 5-aminlevulinic acid as a photosensitiser and APC have been shown to be effective in the ablation of BE, but a comparative trial of these two modalities has not been reported. Materials and Methods: Sixty-eight patients (54 male, 14 female; median age 61 years, range 28-81 years) with biopsy proven BE (median length 4cm, range 2-15cm) were randomized to receive PDT (n=34) or APC (n=34). PDT was performed using 5-aminolevulinic acid (ALA) at a dose of 30mg/kg, followed by laser endoscopy under sedation 4-6 hours later using a windowed balloon applicator and red (635nm) light at 68mW/cm2, with a total fluence of 85J/cm2. APC was administered at a gas flow of 2l/min and power setting of 65W. Multiple treatment sessions (up to a maximum of five) were performed until macroscopic squamous re-epithelialisation was achieved. Endoscopic follow up with 4 quadrant biopsies was performed at 1, 6, 12 and 24 months. Results: All patients in both groups showed a macroscopic reduction in the length of treated BE, with biopsy proven squamous re-epithelialisation. This was greatest in the APC group with 33 of 34 (97%) ablated (median number of treatments 3, range 1-5). In the PDT group complete ablation was achieved in 17 of 34 (50%) (median number of treatments 4, range 1-5). In the remainder, there was a reduction in the length of BE (median reduction 50%, range 5-90%). Buried glands were found in 4 of 17 (24%) of PDT patients, and 7 of 33 (21%) of APC patients. The median follow up is 12 months (range 1-24 months) in both groups. There was one patient with recurrence of BE after 6 months in the PDT group. All patients treated with PDT suffered from transient nausea and vomiting, and there were photosensitivity reactions in 6 patients (17%). Patients treated with APC developed transient odynophagia. One patient developed an esophageal stricture following APC, which required dilatation. There was no other treatment related morbidity. Conclusions: PDT and APC are both effective modalities for ablating BE. PDT requires more equipment and is more costly in the short term. APC appears to be more effective than PDT for ablation of BE, but the impact of both regimes on the development of carcinoma requires larger studies with long-term follow-up.