This page is mainly on CIN, rather than cervical carcinoma.
CIN (cervical intraepithelial neoplasia) is the premalignant condition which can lead to cervical carcinoma.
Incidence of cervical cancer is about 9.3/100 000 and mortality is 2.8/100 000. However, worldwide it is the fifth most common cancer.
The cause is the sexually transmitted human papilloma virus (HPV). There are fifteen different types which increase the risk of cervical cancer, the increase in risk varying depending on which type is present.
HPV is sexually transmitted and so cervical cancer almost solely occurs in the sexually active.
With the advent of screening, it is rare to see cervical cancer clinically. The main symptom is vaginal bleeding but is often asymptomatic in the early stages.
Screening in the UK happens for sexually active women over 25 and 3 yearly in the form of a Pap (Papanicolaou - the bloke who invented it) smear. This involves, via a speculum exam, getting cervical cells with a brush. Essentially, there are different results that can come back. "Unsatisfactory" is fairly self-explanatory; "inflammatory/inconclusive" means there's probably an infection which needs to treated and then the smear repeated; "normal"; and then the different levels dysplasia (aka "dyskariosis" - this term is generally reserved for cervical cells).
Dysplasia is an abnormality in the maturation of cells. CIN is essentially dysplasia in cervical cells and is a precancerous state. There are three stages of CIN - CIN I, II and III.
- CIN I - mild dysplasia. This is repeated after 6 months and if it is abnormal, it is sent for colposcopy.
- CIN II - moderate dysplasia. Send for colposcopy.
- CIN III - severe dysplasia. Send for urgent colposcopy.
This procedure involves putting a camera on the cervix which magnifies the image 10-20 times. It is a better diagnostic tool than a smear test and gives a more accurate idea of the presence and grading of the CIN.
After colposcopy, if CIN II or III is found the transformation zone (i.e. the bit that's CIN) is excised using a procedure called large loop excision of transformation zone (LLETZ). This involves using a diathermy loop (basically, something really hot) to excise the abnormal tissue.
Rarely, this can result in postoperative haemorrhage and the risk of a preterm delivery is slightly increased.
Problems with screening
3-yearly screening has reduced the incidence of cervical cancer by 91% and those who do develop the condition are generally caught early. There are however, a significant number of false negatives. Also, the differentiation between the different levels of dyskaryosis are not clearly defined and CIN often regresses spontaneously.