What are the indications and results of endoscopic resection of early esophageal cancer?
M. Endo, T. Kawano, H. Inoue (Tokyo)
Pathological results in 204 T1 cancers of the esophagus resected in our department between 1985 and 1995 have shown similar incidence of mucosal cancer and submucosal cancer. The incidence of lymph node metastasis was 2% in mucosal cancer patients and 38% in submucosal cancer patients. The incidence of vascular invasion was 9% in mucosal cancer patients and 77% in submucosal cancer patients. Considering the long-term survival rate of superficial esophageal cancer, the 5-year survival rate of mucosal cancer and submucosal cancer was 89% and 70% respectively. A significant difference was observed in these two groups. Thus in mucosal cancer patients of the esophagus the minimally invasive surgery, i.e. the endoscopic mucosal resection (EMR) or the transhiatal esophagectomy is indicated.
Indications for EMR
The indications for endoscopic mucosal resection of esophageal cancer are as follows:
1) mucosal cancer,
2) less than 3 cm x 3 cm in size or less than a third of the circumference of the esophagus,
3) absence of recognizable nodal involvement.
When a lesion suspected to be mucosal cancer is extensive, i.e. more than 4 cm in size or more than two-thirds of the circumference of the esophagus, or when multiple mucosal lesions are found throughout the whole esophagus, transhiatal esophagectomy is indicated when the absence of lymph node metastasis is proved preoperatively.
Procedures of EMR
The procedure most frequently performed in our department employs the suction action of the endoscope. A small transparent cap is attached to the distal part of the conventional forward-viewing endoscope. The snare forceps inserted through the biopsy channel of the endoscope is fully opened inside the cap. The distal part of the endoscope is placed in front of the mucosal lesion. Negative pressure is established at the tip of the endoscope by the suction mechanism of the endoscopic unit. As a result, the esophageal mucosa protrudes like a pseudopolyp inside the cap. The protruding mucosa is strangulated by the snare forceps and resected with blended cauterization current. The resected specimen is collected within the cap. The procedure is repeated until the entire target area of the mucosa has been resected. After completion of EMR, the muscle layer appears. Endoscopic staining with Lugol's solution can confirm that no cancer lesion remains. Staining with Lugol's solution of the resected specimen can also confirm that the entire lesion was removed. The mechanically induced ulcer heals 1 month later without any complications.
Prior to the procedure for resection the important maneuvers must be performed as follows:
1) the extent of the lesion is distinctly demarcated by staining with Lugol's solution;
2) four marks are also placed outside the contour of the lesion by electric cautery;
3) more than 20 ml of physiologic saline solution containing epinephrine is injected submucosally through an endoscopic needle with a syringe to separate the mucosa from the underlying muscle layer. In this maneuver mucosa including the lesion is elevated and separated from the muscle layer.
Clinical results of EMR
EMR was performed in 87 lesions. The most common endoscopic type was the erosive type of lesion (59 lesions), followed by the flat type of lesion (16 lesions). Most resections involved less than half of the circumference of the esophagus. Histologically mucosal cancer was observed in 55 lesions (63%), submucosal cancer in 11 lesions (13%) and dysplasia in 18 lesions. Subsequent treatments were performed for submucosal cancer cases. Concerning postoperative complications, a small fissure was seen in one patient, stenosis in three patients and oozing in three patients. All complications except one stenosis were treated conservatively. For one stenosis, esophagectomy was performed finally.
Long-term survival of EMR patients
The 5-year survival rate was 95%. However, there was no cancer death. All patients died due to other disease; two patients due to liver cirrhosis and another two due to hypopharyngeal cancer. Recurrence and residual multiple lesions has been observed in two patients. These lesions were curatively treated by EMR.