Challenges with Dye Laser against Early Gastric Cancer

Abstract

By taking advantage of dye laser for the tunability of any wave length from visible to near infrared (IR) spectrum, and by introducing it to endoscopy, new diagnostic and therapeutic methods for early gastric cancer (EGC) were developed in our clinic.
In the diagnostic field, it have been succeeded to observe the autofluorescence of cancer tissue gleamed by the stimulation of argon laser (488nm) in 80% (13/16) of EGC. This method is developing further basically by finding more tumor-affinitive fluorescent substances or utilizing CEA monoclonal antibody labelled by fluorescent dye. Not only on diagnosing the extent of cancerous invasion, but also on diagnosing the depth of cancerous invasion, IR laser (805nm) angiography utilizing the deep permeability of IR beam to the stomach wall and injection of ICG (strong absorbant of IR beam) gave very informative findings of “tumor staining” and “pooling phenomenon” on IR-TV endoscope system. This technique is useful, for differentiation between the mucosal and submucosal cancers to find out the risk of lymph node metastasis.
In the therapeutic field, photodynamic therapy (PDT) using hematoporphyrin derivative (HpD) and irradiation of argon dye laser (630nm, CW) showed complete remission of 88% (21/24) of mucosal gastric cancer in high risk patient for laparotomy. Moreover, PDT using excimer dye laser (630nm, PW) resulted in 100% (15/15) cure in the treatment of EGC including submucosal cancer. PDT was a useful method especially treating ulcerated types of EGC which is difficult to treat by the other endoscopic treatment.
In conclusion, dye laser endoscopy is expectable in establishing the method to diagnose very early cancer and cure it at the same time in the near future.