Biomedical subjects

Andrea May

Publications and source records attributed to Andrea May.

22 records · Page 2Linked to original sources

PubMed2003

Barrett's esophagus: endoscopic resection.

In experienced hands, ER is a safe method of resecting dysplastic lesions and early carcinomas of the GI tract, and it has decisive advantages compared with other local endoscopic treatment procedures (such as thermal destruction and PDT). The opportunity for histological processing of the resected specimen provides information regarding the depth of invasion of the individual layers of the GI tract wall. Additionally, it has advantages regarding excision with healthy margins. This means that even when there is infiltration of the submucosa that has not been detected before treatment--in which case local endoscopic therapy is no longer appropriate--a patient with early Barrett's cancer still is able to undergo surgical resection. As was shown recently, the morbidity and mortality of ER are significantly dependent on the frequency with which esophagectomy is performed in each center. When there were more than 20 procedures of this type per year, the surgical mortality was 8%, whereas in centers conducting fewer than 10 procedures per year the rate was 21%. In view of the consequent claim that ER should only be performed at high-volume centers, curative endoscopic treatment of early esophageal carcinomas also should be performed only in centers with a similar frequency to that of the surgical high-volume centers. It is only in these conditions that the conclusion is defensible that patients with HGIN or mucosal Barrett's carcinoma should undergo ER with curative intent instead of radical ER. Randomized and controlled studies comparing radical esophagectomy with endoscopic therapy are desirable, but they are difficult to conduct, not least because valid 5-year survival data show no significant difference between patients who have undergone endoscopic treatment for early Barrett's cancers and the average German population of the same age and sex.

Adenocarcinoma↗

PubMed2003

A prospective randomized trial of two different endoscopic resection techniques for early stage cancer of the esophagus.

BACKGROUND: A variety of different endoscopic resection techniques for early stage cancer of the upper GI tract have been described that are more effective than strip biopsy. However, there is no report of a prospective randomized comparison of different techniques. METHODS: In a prospective randomized study, 100 consecutive endoscopic resections were performed in 72 patients with early stage esophageal cancer. Fifty endoscopic resections were performed with a "suck-and-ligate" device without prior submucosa injection and 50 with the cap technique with prior submucosa injection of a dilute saline solution of epinephrine. The main assessment criteria were maximum diameter of the resection specimen and of the resection area, and the complication rate. RESULTS: No significant differences were observed between the two groups with regard to the maximum diameters and calculated area of the resected specimens (ligation group: 16.4 [4.0] x 11 [3.1] mm/185 [84] mm(2) vs. cap group: 15.5 [4.1] x 10.7 [2.7] mm/168 [83] mm(2)), or the maximum diameters and calculated area of the endoscopic resection ulcers after 24 hours (ligation group: 20.6 [4.8] x 14.3 [4.5] mm/314 [160] mm(2) vs. cap group: 18.9 [5.1] x 12.9 [3.8] mm/260 [145] mm(2)). There was only a slight advantage (greater diameter of resection specimens) for the ligation group in patients who had prior endoscopic treatment. There was one minor episode of bleeding in each group; there was no severe complication. In 41 of 72 patients (57%), further endoscopic therapy after endoscopic resection was necessary because of residual neoplasia at the first follow-up endoscopy after resection (61 of 100 resection specimens [61%] had lateral margins that could not be evaluated because of coagulation artifact or contained malignancy but with the base of the lesion free of tumor). CONCLUSIONS: The cap technique with submucosa injection and the ligation technique without submucosa injection are similar with respect to efficacy and safety for endoscopic resection of early stage esophageal cancers.

Esophageal Neoplasms↗

PubMed2002

Photodynamic therapy of human Barrett's cancer using 5-aminolaevulinic acid-induced protoporphyrin IX: an in-vivo dosimetry study in athymic nude mice.

OBJECTIVE: There has been a dramatic increase in recent years in the incidence of Barrett's oesophagus and the oesophageal adenocarcinoma associated with it. Alongside surgical treatment for early Barrett's carcinomas, endoscopic treatment procedures such as photodynamic therapy (PDT), which have much lower complication and mortality rates, will play an increasing role in the future. In this study, the effects of light energy dose, light fractionation and oxygenation on the efficacy of PDT were investigated for the first time in an in-vivo nude mice tumour model bearing a human Barrett's carcinoma. DESIGN: A total of 387 NMRI strain (nu/nu) nude mice with thymic aplasia (total 53 controls) were transplanted with human Barrett's carcinoma and treated with laser light at 635 nm (light dose 0-200 J/cm2, fluence rate 400 mW/cm2). 5-Aminolaevulinic acid-induced protoporphyrin IX (5-ALA-PpIX) (100 mg 5-ALA/kg body weight administered orally) was used as the photosensitizer. METHODS: Fractionation studies were performed at 0, 50, 100 and 150 J/cm2. The light dose was administered in four equal fractions divided by three irradiation-free intervals of 120 s. Oxygenation studies were carried out at 150 J/cm2 with simultaneous oxygen supply of 2, 6 and 8 l oxygen/min. RESULTS: Dosimetry studies demonstrated a positive correlation between increase in light dose and tumour destruction up to 150 J/cm2 when using either continuous or fractionated light delivery. The optimal light energy dose was 150 J/cm2. Neither fractionation of light nor simultaneous oxygenation enhanced the efficacy of the PDT. CONCLUSION: This is the first study in the literature that proves the efficiency of PDT with 5-ALA-PpIX in human Barrett's adenocarcinoma and that demonstrates an exact dosimetry of the optimal light energy dose (150 J/cm2). No general recommendation can be made for the use of fractionation or oxygenation in clinical PDT.

Adenocarcinoma↗

PubMed2002

Local endoscopic therapy for intraepithelial high-grade neoplasia and early adenocarcinoma in Barrett's oesophagus: acute-phase and intermediate results of a new treatment approach.

BACKGROUND: Radical oesophageal resection has until now been regarded as the gold standard for treatment in intraepithelial high-grade neoplasia or early adenocarcinoma of the oesophagus. However, the mortality and morbidity rates are substantial. DESIGN: A new therapeutic approach involving low-risk endoscopic therapy modalities was examined in the framework of a prospective study. PATIENTS: A total of 115 patients with intraepithelial high-grade neoplasia (19) and early adenocarcinoma (96) in Barrett's oesophagus. METHODS: Endoscopic mucosal resection (EMR) was used in 70 patients, and photodynamic therapy (PDT) was used in 32 patients. The two procedures were combined in ten patients. Three patients underwent primary treatment with argon plasma coagulation (APC). The average follow-up was 34 +/- 10 months (range 24-60 months). RESULTS: Complete local remission was achieved in 98%. The overall complication rate was 9.5%. Major complications, such as perforation and severe bleeding, did not occur. Minor complications included not haemoglobin relevant bleeding (drop of haemoglobin less than 2 g/dl) (5) and stenosis (3) after EMR, and long-lasting odynophagia (1) and sunburn (2) after PDT. In all, 13 patients have died so far, but in only one case due to the underlying disease. The calculated overall 3-year survival rate is 88%. During the follow-up period, a 30% rate of metachronous lesions was observed; endoscopic therapy was performed successfully in all but one of these patients. CONCLUSIONS: These good acute-phase and intermediate results, along with low morbidity rates and no mortality, suggest that the organ-preserving local endoscopic procedure including EMR and PDT is an attractive alternative to oesophageal resection. Therefore, endoscopic therapy might replace radical oesophageal resection in future in cases of intraepithelial high-grade neoplasia and early mucosal adenocarcinoma in Barrett's oesophagus.

Adenocarcinoma↗