| Objective: Esophageal dysplasia belongs to the precancerous state of esophageal carcinoma. If an effective therapy could be employed to treat the esophageal dysplasia, the occurrence of esophageal carcinoma would be blocked. Argon plasma coagulation (APC) is a diathermy-based non-contact technique, high frequency energy is transmitted to tissue by ionized argon plasma In this study, we found the safe and effective settings (power, separation, exposure time, angle, flow rate and the submucosal liquid injection) by experiments on pig esophagus and fresh in vitro surgically resected normal esophagus. Then we used APC to treat the patients who suffered with esophageal precancerous lesions, and observed the effect of the treatment.Methods: 1. Animal and in vitro esophagus experiments: The effect of APC was studied on two pig esophagus and two fresh in vitro esophageal resection specimens using power settings of 40, 60, 99watts, pulse duration of 1 and 3 seconds at 30 degree, with 1mm and 2mm separation, and a flow rate of 1.6 L/min, and various submucosal liquids injections. Histological appearance and measurement of depth and length of tissue damage area were made through lightmicroscope. A scoring system for depth of tissue damage was created to evaluate the relationship of tissue damage with the various settings. 2. Clinical patients treatment: From July 2000 to July 2001, Twenty-eight patients suffering from histologically confirmed moderate and severe esophageal dysplasia were treated with APC. Firstly, 1.5% Lugol's was performed after plain endoscopy, it was scattered and spread on suspicious regions to help to distinguish the dysplasia area. Then APC was used to ablate a spot larger than the dysplasia area by 0.5cm to the margin of the lesion to be ablated. Mixtures of 10% G.S, 0.9%N.S, 0.005% adrenalin, 1% lidocaine was injected into the submucosa under the lesion. The lesion was ablated with APC, using power setting of 40 watts, separation of 1mm, flow rate 1.6L/min until the lesion was all black, which means that the lesion was destroyed completely. A follow-up examination of plain endoscopy with Lugol's solution test and histopathological study was used after 1, 3, 6 months.Results: 1. Animal and in vitro esophagus experiments: The color of the damaged area was black in the center and gradually changed into brown-yellow and white in the surrounding area. The changing of color reflects the severity of tissue damage. The white color indicates that the epithelia were destroyed, and in the black area the tissue damage deepened to submucosa. The depth varied likes wedge-shaped defect. By statistical analysis, tissue damageincreases with the increasing of power setting and pulse duration, decreases with the increasing of separation, and injection makes the damage much shallow. 2. Clinical patients treatment: Twenty-eight cases was treated. Twenty-six cases healed (Twenty-three cases was treated by 1 sessions, three cases was treated by 2 sessions). One case was found with mild dysplasia. Another case was treated by 3 sessions (The lesion extend to the entire circle of the esophagus) and after a 3 months follow-up, the case was found with moderate to severe dysplasia. No perforation, hemorrhage and stricture were obtained. No occurrence of esophageal cancer was observed.Conclusion: 1. Early detection, diagnosis and treatment is the essential method to decrease the incidence and mortality of esophageal cancer. 2. Routine endoscopic Lugol's solution test is effective for detection of esophageal precancerous lesion, and APC is a new method of curative treatment, we first used this method to treat the esophageal precancerous lesion and had obtained a good result. 3. Though the animal and in vitro esophageal experiments, we find out the safe and effective combination of power setting (40w), flow rate (1.6L/min), separation (1mm) and pulse duration (3 seconds). Submucosal injection is an important method to improve the safety of APC ablation. 4. APC has following advantages: First, it can be used to t... |
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