[Photodynamic therapy (PDT) for early cervical cancer]

The incidence of carcinoma in situ (CIS) and dysplasia of the uterine cervix has been increasing among young women in recent years. Most of these patients want to preserve their fertility. Also, to accommodate high-risk patients with complications, elderly patients, and those who refuse surgery, we perform PDT as a method to preserve fertility. The technique required for PDT is relatively simple, and can be performed without anesthesia, since it causes no pain or bleeding. PDT, with the use of Excimer Dye Laser (EDL), a type of low pulse laser, has a considerably higher degree of tissue penetration, even compared to PDT using Argon Dye Laser (ADL). Also, PDT using EDL can manage glandular involvement of CIN, and its special feature of selective destruction of malignant cells with almost no effect on normal tissues is noteworthy. Beginning in 1995, PDT using YAG-OPO Laser with a variable laser wavelength has been performed. PDT is performed 48 hours after intravenous injection of 1.5 mg/kg to 2 mg/kg photosensitizer Porfimer sodium (PHE) when the difference in density of PHE becomes greatest between malignant cells and normal tissue. The most advanced features of our method compared to conventional radiation which uses cut fiber are: First, by using colposcope with an optical path for the laser, it is possible to show a 10 mm circular spot at the focus of observation. With this method, cervical lesions can be observed and checked while receiving stable and precise photoradiation by using colposcope through direct observation. Second, for cervical canal treatment, by using a cervical probe to administer photoradiation in the forward direction in the cervical canal and to the side walls, 70% of the laser light is scattered to the side walls, so that all of the cervical canal can be radiated. Also, the cervical canal probe used to administer photoradiation, by inserting 2 cm to 3 cm depending on the conditions of the cervical canal and withdrawing the probe 1 mm, can be performed precisely and promptly by using the cervical probe manipulator feature of the colposcope. At the present time, studies using the PDT method have been conducted on 56 patients (39 CIS and 17 dysplasia patients). Out of these 56 patients, there were 54 CR (96.4%), only one NC, and one PR with very limited remnants but most of the lesions had disappeared. The NC was highly suspected to be invasive carcinoma and the PR was CIS. In the CIS case, some remnant was evident at the end of the cervical canal, and PDT was administered again. After this treatment, it became CR. This was 10 months ago, and no abnormal condition has been reported since. The first CR case was reported 6 years ago among the 56 cases studied, and no recurrence has been observed to date. Five patients became pregnant after the treatment. Four had normal deliveries and one had a cesarean section. PDT's side effect is similar to symptoms of sunburn such as minor skin irritation due to sensitive reaction to sunlight. Normally, it can be relieved by applying carmine lotion, and even cases that required treatment were cured completely within a few days after applying steroid ointment. Before hospitalization, if the patient gets a sunburn from being outside, the sensitive reaction to laser light is almost nonexistent. Thus, we advise patients to get some exposure to the sun before being hospitalized. Also, in cases where strict shading time is observed, side effects are not apparent at all, and no abnormal findings are recognized in the blood and urine due to using PHE. With almost no side effects, bleeding or pain, and with certain improvements in administration methods, a better choice of photosensitizer which would shorten the shading time, PDT is considered to be the best therapy for treating CIS and dysplasia while preserving fertility.