4. Pathogenesis of cervical cancer
CIN and squamous cell cervical carcinoma It is widely accepted that invasive squamous cell carcinoma of the cervix, which is the commonest histological type, is preceded by a pre-invasive stage of the disease, where the abnormal cells are confined to the epithelium. This stage of non-invasive disease is known as cervical intraepithelial neoplasia (CIN) and is directly […]
Function of the cervix
The uterine cervix primarily acts as a physical barrier between the external environment (vaginal canal) and the uterus. The cells lining the endocervical canal produce both acid and neutral mucin, which contains electrolytes (mostly sodium chloride) and simple sugars (glycogen) in colloidal solution. This mucus forms a plug in the os blocking the passage of foreign […]
Risk of progression of CIN3 to invasive carcinoma
The risk depends on: Type of HPV Other risk factors in the individual woman Time allowed for progression. Modelling and follow-up studies have estimated progression rates between 12% and 40% (Gustafsson & Adami 1989; Ostor 1993; Peto et al. 2004; McCredie et al. 2008). The interval between carcinoma in situ (peak incidence age 30 years) […]
The columnar epithelium of the endocervix
The epithelium that lines the endocervical canal and endocervical crypts consists of a single layer of mucus-producing columnar cells. These cells are tall and cylindrical and are arranged in a picket fence formation. The nuclei are mostly situated basally, adjacent to the basement membrane, but during active mucous secretion the nucleus can be displaced by […]
Adenocarcinoma and adenocarcinoma in situ
Adenocarcinoma Adenocarcinoma of the cervix is a malignant neoplasm that involves the glandular epithelium of the cervix. There are several types of adenocarcinoma, most of which have similar aetiology and risk factors to squamous cell carcinoma. Endocervical-type mucinous adenocarcinomas comprise 70% of adenocarcinomas (WHO). HPV types commonly associated with adenocarcinoma are 16, 18 and 45 […]
Metaplastic change in the cervix and its physiological basis
Metaplasia is the name given to the process by which one fully differentiated type of epithelium appears to transform into another differentiated type. It is usually an adaptive change that occurs in in reaction to chronic irritation, or in response to hormonal stimuli. As the female goes through puberty and reaches maturation, hormonal changes cause […]
Clinical presentation, stages and treatment of cervical cancer
The clinical presentation and pattern of growth of invasive cervical cancer is variable. The tumour may be polypoid, papillomatous or fungating, or it may be flat or ulcerating (Figure 4.7). Initially, like most cancers, there is local spread or growth; it travels upward into the body of the uterus, downward into the vagina or laterally into the pelvic folds. Eventually the […]
5. The principles of screening and measurement of accuracy
Principles of screening With reservations predicted by the authors at the time, cytological cervical screening has to a major extent fulfilled the criteria defined by Wilson & Jungner (1968) (Figure 5.1). These principles have been revisited more recently by Andermann et al. (2008) in the knowledge of high-risk HPV being a necessary cause of cervical […]
References
Andrae B, Andersson T M-L, Lambert PC et al. (2012). Screening and cervical cancer cures: population based cohort study. BMJ e900. Doi: 10.1136/bmj.e900. Austin RM, Zhao C (2012). Type 1 and type 2 cervical adenocarcinomas: some cervical cancers are more difficult to prevent with screening. Cytopathology 23:6-12. Bansal N, Wright JD, Cohen CJ, Herzog TJ […]
Squamous epithelium
Squamous epithelium of the cervix and vagina is non-keratinising and is composed of a continuous layer of stratified (multi-layered) flat, polygonal cells with centrally located nuclei. The stratified squamous epithelium of the cervix can be divided into three layers: the superficial, intermediate and parabasal/basal layer. Stratified squamous epithelium has a mainly protective function but also […]