Cervical precancerous lesions

Cervical precancers are intraepithelial preinvasive lesions that slowly progress to invasive cancer. This development takes about 10-15 years.

Clasification
The Bethesda 2001 system was used to classify the cytological finding, the division into CIN 1, CIN 2 and CIN 3 was used for histological classification. At present, the division is unified under the Bethesda system. The Bethesda 2001 system has 97% specificity; however, the false negativity is 15-40%. This is why the examinations are repeated every year in order to detect false negative lesions in previous years, although the progression takes about 10-15 years.

We discriminate lesions of the squamous epithelium and lesions of the cylindrical epithelium.

Squamous epithelium
According to the finding, there are:

Precancerous lesions include LSIL and HSIL.
 * 1) normal finding (negative for intraepithelial lesions or malignancy, NILM);
 * 2) atypical squamous cell epithelium (ASC), or atypical squamous cell epithelium of undetermined significance (ASC-US) and atypical squamous cell epithelium for which high-grade lesions (atypical squamous cells) cannot be ruled out, ASC-H);
 * 3) Low-grade squamous intraepithelial neoplasia (LSIL) - corresponds to the old histological classification CIN 1 (lesions affecting only basal 1/3);
 * 4) High-grade squamous intraepithelial neoplasia (HSIL) - combines CIN 2 (basal 2/3 mucosa) and CIN 3 (more than basal 2/3 mucosa, ie carcinoma in situ, CIS) histological classification;
 * 5) invasive cancer.

Cylindrical epithelium
According to the finding, we distinguish:


 * normal finding (NILM);
 * atypical glandular cells not otherwise specified (AGC-NOS);
 * atypical cylindrical epithelium suspected of carcinoma in situ or invasive carcinoma (AGC-neoplastic);
 * adenocarcinoma in situ (AIS);
 * invasive adenocarcinoma.

Risk factors
For squamous cell epithelial lesions, the main risk factor is chronic HPV infection, which is also associated with indicators of risky sexual behavior (sexually transmitted infections, especially chlamydia and HSV-2, promiscuity - more than 6 life partners, early coitarché, high birth rates, hormonal contraception). In the LSIL (CIN 1) stage, the immune system is usually able to destroy the lesion. However, if the immune system is damaged in some way, the lesion progresses to the HSIL stage (CIN 2 and CIN 3) and further to invasive cancer. Therefore, other risk factors include immunosuppression, immunoincompetence and smoking.