ORGANUM
Cervical cancer is the fourth most common female cancer worldwide. Incidence varies across the world. In many low resources countries, this is the most common cause of death from cancer in women. In the UK, cervical cancer is the fourteenth most common, with 3200 new cases per year, with the highest incidence rates in the 25-29 age group between 2013 and 2015. Cervical cancer has several histological types, of which SCC accounts for about 70%-80%, while adenocarcinoma accounts for about 10%-25%. Other subtypes such as adenosquamous, neuroendocrine and undifferentiated carcinomas, are uncommon.
The most important risk factor for cervical cancer is persistent HPV infection. Factors leading to higher risk for persistent HPV infection are risk factors for cervical cancer:
Early age of first intercourse
Number of partners
Smoking
Low-socioeconomic status
Immunosuppression
Almost all cases (over 99%) are caused by high-risk HPV infection. There are more than 100 subtypes of HPV infection. HPV can affect genital and non-genital sites. High-risk subtypes are associated with cancer, while the low-risk subtypes cause warts. Amongst the 14 high-risk subtypes, HPV16/18 cause about 70% of cervical cancers. HPV infection is transmitted via close skin-to-skin contact such as genital-to-genital contact and anal, vaginal and oral sex. It is a very common infection, where the majority of sexual active women would have been infected sometime during their lifetime. However, most infections are transient and are cleared by the body's natural immunity. Apart from cervical cancer, HPV infection also causes other cancers such as vulval, vaginal, anal and oropharyngeal cancers.
The squamocolumnar junction (SCJ) is the junction between the squamous epithelium of the ectocervix and the columnar epithelium in the endocervix. The SCJ moves in relation to the anatomical cervical OS. Changes in oestrogen during puberty, pregnancy, or while on the COCP moves the SCJ outwards, exposing columnar epithelium to the lower pH of the vagina. This reacts by undergoing transformation back to squamous epithelium by a process of squamous metaplasia. The area that lies between the current SCJ and that is reached as it moves outwards across the ectocervix is the transformation zone, and it is here that most preinvasive lesions occur.
The terminology used in the UK for reporting cervical smears was introduced by the British Society for Clinical Cytology in 1986 and updated in 2013. The term dyskaryosis is used to describe those cells that lie between normal squamous and frankly malignant cells and exhibit degrees of nuclear changes before malignancy. Atypical glandular cells may represent premalignant disease of the endocervix or endometrium.
Malignant cells show nuclear enlargement at the expense of cytoplasmic mass. The nuclei may assume a lobulated outline. There is increased intensity of staining of the nucleus and an increase in the number of mitotic figures.
High-risk HPV testing has a sensitvity