[Studies on Nd:YAG laser therapy for cervical intraepithelial neoplasia]

Basic and clinical studies were performed to establish the value of Nd:YAG laser therapy for treating cervical intraepithelial neoplasia (CIN) with preservation of the uterus. The basic studies revealed that application of a surgical rod with a 0.4 mm tip at an output of 20 watts was the most suitable. Its use produced an excellent cone specimen, and there was no difficulty in making a histopathological diagnosis of the lesion. The layer of coagulation produced by the contact laser with microchip at a 20 watt output was 0.36 mm thick with 1 second of irradiation. This layer became thicker as the coagulation time became longer. Thus, necrosis of the residual lesion could be produced together with hemostasis. A clinical study was performed in 329 patients with CIN who were treated from September 1983 through December 1988 with Nd:YAG laser therapy. The preoperative diagnosis was mild dysplasia in 94 patients, severe dysplasia in 97, and carcinoma in situ in 138. Contact Nd:YAG laser conization (method A) was used in 272 cases, and Nd:YAG laser vaporization (method B) in 57 cases. After a single treatment, the overall cure rate was 97.6%. This high cure rate was obtained because irradiation technique most suitable for each lesion was chosen from among five techniques at the time of colpo.cervicoscopy. The cure rate was 98.9% with method A, and 91.2% with method B. Using method A, a deeper layer of coagulation necrosis was produced in the cone bed so that any residual was eliminated. In addition, using method A a cone specimen could be obtained to facilitate the histological diagnosis after operation and to determine the adequacy of excision. Accordingly, when there was incomplete excision, the prognosis could still be judged from histological examination of the lesion. The histological appearance of the cone specimen was valuable in planning the follow-up and further treatment where necessary. There were no serious side effects with either method. The average time required for therapy was 11.4 minutes with method A and 12.2 minutes with method B. From the review of the incompletely excised cases using method A, the uterus-preserving therapy is recommended when preoperative biopsy findings agree with or overestimate cytologic and colpo.cervicoscopic findings. Neither method A nor B affected fertility. Cervical healing and the incidence of subsequent pregnancies were very satisfactory with both methods. These results show that Nd:YAG laser therapy is very effective in CIN and can allow the uterus to be preserved.(ABSTRACT TRUNCATED AT 400 WORDS)