Microinvasive carcinoma of the uterine cervix.

Radical hysterectomy and pelvic lymphadenectomy were performed on 135 patients with Stage I epidermoid carcinoma of the uterine cervix invading less than 5 mm below the basement membrane. These cases were studied to determine the biological behavior of early invasive carcinoma and to establish diagnostic criteria for microinvasive carcinoma of the cervix (Stage IA). None of the 135 patients had metastasis to the parametrial tissue in the final surgical specimen. One (0.9%) of 106 patients with invasion up to 3 mm had lymph node metastasis, while 4 (13.9%) of 29 patients with invasion of 3.1-5 mm had nodal metastasis. Of the 106 patients with invasion up to 3 mm, 25 had confluent invasion. None of the 25 patients had lymph node metastasis. In view of our result, carcinomas with invasion less than 3 mm may be regarded as a separate diagnostic group because of their limited metastatic potential, and may be treated by conservative methods used for carcinoma in situ, even if there is a confluent pattern. For carcinoma with invasion of 3.1-5 mm, more extensive procedures as used for frankly invasive carcinomas are probably necessary.