Multifocal FIGO stage 1A1 cervical squamous carcinomas have an extremely good prognosis equivalent to unifocal lesions.

Early invasive squamous carcinomas of the cervix are sometimes multifocal. There are few guidelines regarding how to measure multifocal carcinomas and options include measuring from the edge of 1 invasive focus to the edge of the furthest invasive focus, adding the maximum horizontal dimension of each invasive focus together or regarding multiple foci as representing distinct small areas of invasion and if clearly separate measure them individually. For tumors with a shallow depth of invasion (<3 mm), this has implications for staging and management because if the maximum horizontal dimension is taken from the edge of 1 invasive focus to the edge of the furthest invasive focus, this could represent a International Federation of Gynaecology and Obstetrics (FIGO) 1B1 carcinoma, whereas alternatively these could be regarded as separate foci of 1A1 disease. It has been our practice to regard such lesions as representing multiple foci of invasion (multifocal FIGO 1A1 carcinomas) if clearly separate, arbitrarily defined by us as a minimum of 2 mm between each separate focus of invasion. In this study, we have obtained follow-up in a series of "multifocal 1A1 cervical squamous carcinomas" treated by local excisional methods (large loop excision of transformation zone or cone biopsy) with margins clear of premalignant and malignant disease. The study included 22 cases, 11 of which (50%) would have been regarded as FIGO stage 1B1 if the horizontal dimension had been measured from the edge of 1 invasive focus to the edge of the furthest invasive focus. In none of the cases was there evidence of recurrence of premalignant or malignant disease during follow-up (9-91 mo; mean and median 48 and 45.5 mo, respectively). Although limited by a relatively small number of cases, our results support the hypothesis that with regard to tumor staging and management, it is best to consider multifocal lesions as representing separate individual foci of invasion, to measure each focus separately, and to determine the FIGO stage on the basis of the highest FIGO stage of an individual focus.