Tumors should be measured in 3 dimensions in all cases, namely the depth of invasion and 2 measurements of horizontal extent (longitudinal/length and circumferential/width). Larger tumors are more accurately measured grossly, while smaller tumors and some larger tumors with a diffusely infiltrative pattern or with marked fibrosis are best measured microscopically. It is best to report only 1 set of tumor measurements based on a correlation of the gross and microscopic features to avoid confusion.

The depth of invasion is measured from its HSIL origin, that is, from the base of the epithelium either surface or glandular that is involved by HSIL to the deepest point of invasion. If the invasive focus or foci are not in continuity with the dysplastic epithelium, the depth of invasion should be measured from the deepest focus of tumor invasion to the base of the nearest dysplastic crypt or surface epithelium. If there is no obvious epithelial origin, the depth is measured from the deepest focus of tumor invasion to the base of the nearest surface epithelium, regardless of whether it is dysplastic or not. In situations where carcinomas are exclusively or predominantly exophytic, there may be little or no invasion of the underlying stroma. These should not be regarded as in situ lesions and the tumor thickness (from the surface of the tumor to the deepest point of invasion) should be measured in such cases. The depth of invasion below the level of the epithelial origin should not be provided in these cases as this may not truly reflect the biological potential of such tumors. If it is impossible to measure the depth of invasion, eg, in ulcerated tumors or in some adenocarcinomas, the tumor thickness may be measured instead, and this should be clearly stated on the pathology report along with an explanation for providing the thickness rather than the depth of invasion.

Horizontal extent: The longitudinal extent (length) of horizontal extent is measured in the superior-inferior plane (ie, from the endocervical to ectocervical aspects of the section), whereas the circumferential extent (width) is measured or calculated perpendicular to the longitudinal axis of the cervix. If the tumor involves only 1 block, the circumferential extent (width) will be 2.5 mm to 3 mm (thickness of 1 block). When more than 1 block is involved, it is the product of the number of consecutive blocks with tumor and thickness of a block.

The LAST definition of superficial invasive squamous cell carcinoma (SISSCA) conforms to T1a1/ FIGO 1A1. The LAST consensus recommends SISCCA to include multifocal disease and that reporting include presence, number, and size of independent multifocal carcinoma, however, no LAST recommendation was made on the methodology to measure multifocal disease. A recent publication by Day et al states that multifocal tumors should be defined as invasive foci separated by a tissue block within which there is no evidence of invasion or as invasive foci in the same tissue block that are more than 2 mm apart, or as invasive foci on different cervical lips. They recommend that multifocal tumors should be staged based on the largest focus.