Diagnosis of Cervical Intraepithelial Neoplasia with Special Reference to Roles of Cervical Cytology and Colposcopy

Abstract

With the integration of cytology into the cervical cancer screening, the mortality rate of cervical cancer has dramatically decreased. Cytology has since been incorporated into the cervical cancer screening. The revised Bethesda System for cervical cancer screening now includes sections that address the quality of cytological specimens and that highlight the limitations of cytology. The most significant topic, especially in the revised 2001 edition, is the introduction of the concept of human papillomavirus (HPV) infection into cytology. However, cytology is significantly less sensitive than the molecular biological method, PCR. Initial screening using a highly sensitive method followed by a high-specificity cytology triage is therefore an appropriate screening algorithm.

Aging and pregnancy pose two specific issues with regard to cytology in Japan. As the Japanese population is aging rapidly, the interpretation of cytology must take into account aging-dependent factors that modulate readouts. With regard to pregnancy, it is often the case that cytology tests are first performed in women once they become pregnant; younger women are rarely offered such tests.

Colposcopy is performed as a workup test for patients who have received abnormal results following cervical cancer screening or for those individuals in whom abnormal cervical morphologies are detected following visual inspection. Colposcopy is predominantly used for detecting high-grade squamous intraepithelial lesions rather than overt invasive carcinoma. Inter-observer bias is also common. It has also been reported that different levels of cytology knowledge and experience between colposcopists can lead to diverse interpretations of colposcopy results. This had led to the creation of a system that standardizes the grading of lesion severity so that results are concordant between examiners. Most CIN3 lesions are flat. In contrast, nodular, papillary, or have outgrowing contours and are indicators of the precursors to invasive cancer. Ulcers are associated with invasive carcinoma. The highest grade lesion, an opaque white color, often described as a deep white or oyster gray, may be where the acetic acid-induced white coloration is most persistent. The distance between vessels in CIN3 lesions is heterogeneous compared to CIN1. The timing of the colposcopy during pregnancy is important for accurate diagnosis. Ideally, colposcopy and histology results should be obtained in the first 20 weeks of gestation to yield robust and concordant data.