Cervical Smears

Cervical screening is not a test for cancer. It is a method of preventing cancer by detecting and treating early abnormalities that, if left untreated, could lead to cervical cancer. The National Screening Programme came about following Health of the Nation (DH, 1993). Since its implementation, the NHS Cervical Screening Programme has been remarkably successful. It has saved a large number of women's lives and will continue to prevent about 4,500 deaths every year in England.

ELIGIBILITY

All women between the ages of 25 and 64 are eligible for a free cervical smear test every three or five years.

Reasons why women under 25 and women over 65 are not invited for cervical cytology (Sasieni et al., 2003):

• Invasive cancer in women under 25 is rare, but changes in the cervix are common. This may mean that younger women may get an abnormal result when there is nothing wrong.

• Evidence suggests that screening women under the age of 25 may do more harm than good by resulting in unnecessary investigations after false positive results. It is suggested that screening women from the age of 25 will help reduce anxiety as well as the number of unnecessary investigations and treatments in younger women.

• Women aged 65 and over who have had three consecutive negative cervical tests in the preceding ten years are taken out of the recall system. The natural history and progression of cervical cancer means it is highly unlikely that such women will go on to develop the disease.

• Women aged 65 and over who have never had a screen are entitled to one.

The NHS call and recall system invites women to attend their local GP for a screen. Women must be advised to register with a local GP clinic.

RISK FACTORS FOR CERVICAL CANCER

• Certain types of human papilloma virus (HPV) are linked with around 95 per cent of all cases of cervical cancer (mainly types 16,18, 31, and 33).

• Women with many sexual partners or whose partners have many partners.

• Long-term use of oral contraceptives increases the risk (taking the combined oral contraceptive for 5 years or more in the presence of HPV virus). Condom use gives some protection.

• Women who smoke are twice as likely to develop cancer as non-smokers.

• Women with late first pregnancy have a lower risk than those with an early pregnancy; the risk increases with the number of pregnancies.

• Women in manual social classes are more at risk than those in a non-manual social class.

Assessment of the cervix

The cervix is composed of two types of epithelium.

Columnar epithelium is generally inside the cervical canal, and therefore not usually seen. It is translucent and blood vessels are visible.

Squamous epithelium covers the intravaginal portion of the cervix. Its appearance is opaque and dull to the eye.

Where the different epithelia meet is the squamo-columnar junction (S-C J).

This exposed area of columnar epithelium on the ectocervix, over a number of years, is replaced by squamous epithelium by a process of metaplasia. This area is known as the transformation zone. It is this part of the transformation zone that is adjacent to the squamo-columnar junction that is most vulnerable to cervical intraepithelial neoplasia. Therefore, when the squamo-columnar junction is visible, the cervical sample must include the whole circumference of the S-C J and the adjacent 1 cm of squamous epithelium.

As has been mentioned, columnar epithelium appears red to the eye. While this is sometimes referred to as an 'angry' cervix, 'erosion' (though the surface is not eroded), or 'ectopy' (though the columnar junction is not ectopic or misplaced) a more accurate term is eversion. Laceration of the cervix associated with childbirth (ectropion) may expose more of the canal lined by columnar epithelium. This may be further exaggerated by opening the speculum. Nabothian follicles may also be seen on the cervix. As a result the cervix may have a knobbly appearance. These are mucus-retaining cysts caused by normal changes of surface columnar squamous epithelium. They are generally around 5 mm in diameter, but may be enlarged to 1 to 1.5 cm. Polyps may be seen on the cervix. Most are entirely benign and give rise to no symptoms.

Clinical suspicion of malignancy may include: an enlarged cervix with an irregular friable surface that is crumbling to the touch, large blood vessels that may bleed freely when rubbed by the end of the speculum, and sweet smelling but offensive watery discharge (NHSCSP, 1998).

METHODS OF SCREENING

The first stage in cervical screening is either a smear test or liquid-based cytology (LBC).

Smear test (traditional)

A smear test involves a sample of cells that have been taken from the transformation zone (TZ) of the cervix for analysis. This is done by speculum examination: a spatula is used to sweep around the TZ; if the TZ is not visible, a cervical brush should be used as well.

Liquid-based cytology

Liquid-based cytology (LBC) is a technology whereby a cervix brush sample is suspended in buffer and processed so that a thin layer of cells is produced on a slide without contamination by blood cells and debris. This results in preparations that are generally easier to read. Its advantage is in a reduction in inadequate samples from 9 per cent to 1-2 per cent, and there may be gains in reducing borderline results and increasing sensitivity.

WOMEN'S SEXUAL HEALTH 153

RESULTS AND TREATMENT FOLLLOWING CERVICAL SMEAR

Table 15

Explanation

No abnormalities detected

Cellular appearances which cannot be described as normal

Endocervical cell changes Squamous cell changes

Cellular appearances consistent with CIN 1

Cellular appearances consistent with CIN 2 Celluar appearances consistent with CIN 3 Possibility of invasive cancer

Grade

Negative

Abnormal Borderline changes

Mild dyskaryosis

Moderate dyskaryosis

Severe dyskaryosis

Suspected invasive cancer

Inadequate

The test cannot be interpreted. It may be too thick or too thin, obscured by inflammatory cells or blood, or incorrectly labeled; or it does not contain the right type of cell.

Action

Routine recall after three to five years

Refer for colposcopy after one borderline change or three abnormal tests at any grade in a ten-year period

Refer for colposcopy after one test is reported as borderline.

Refer for colposcopy after three tests in a series are reported as borderline.

Ideally refer for colposcopy, but it remains acceptable to recommend a repeat test after one test reported as mild dyskaryosis. If two tests are reported as mild dysdaryosis refer for colposcopy.

Refer for colposcopy

Refer for colposcopy

Refer for colposcopy Women should be seen urgently within two weeks of referral.

Repeat the best. Refer for colposcopy after three consecutive inadequate samples.

Source: NHS Publication No. 20: Colposcopy and Programme Management Guidelines for the NHS Cervical Screening Programmes.

Treatment

• There are two main methods of treatment. The abnormal cells in the cervix may be destroyed using laser ablation or cold coagulation treatments, or the abnormality may be excised using a loop diathermy or laser excision. Loop diathermy is the most common and effective treatment, and is used by 71 per cent of clinics.

• Hysterectomy is not usually necessary for CIN, as treatment aims to preserve a woman's fertility.

• Surgery is the main form of treatment for localised cases for the few women who have cancer, while radiotherapy and chemotherapy may be used for more extensive disease.

SPECIAL CONSIDERATIONS (NHSCSP (2004)): Cervical cytology in GUM Clinics

The NHS Cervical Screening Programme (2004), suggests that cervical cytology in GUM clinics should be reserved for those with a cytological indication or those who have not been screened in previous routine screening at the appropriate interval.

Cervical screening in pregnancy

Unless a pregnant woman with a negative history has gone beyond three years without having a cervical screening then the test should be postponed. If a woman has been called for routine screening and she is pregnant then the test should be deferred. If an earlier test was abnormal, and in the interim the woman becomes pregnant, then the test should not be delayed, but should be taken in the middle trimester unless there is a clinical indication.

HIV-positive women

All women newly diagnosed with HIV should have cervical surveillance performed by, or in conjunction with, the medical team managing the HIV infection. Annual cytology may be indicated depending on disease progression, refer to local guidelines. Colposcopy for cytological abnormality should follow national/local guidelines. As there is a lack of information on the management of women from the age of 65 who are HIV-positive, it is advisable to seek local guidance in these cases.

Women who have sex with women

There is no mention of management of smears for women who have sex with women in the national screening guidelines. They do recommend that women who are not sexually active, but have had sex with men in the past, continue with the screening programme. There appears to be an overall lack of information on the cervical screening needs of women who have sex with women. It is worth noting, however, that Fethers et al. (2000) highlight no difference in the prevalence of abnormal cervical cytology and of changes suggestive of cervical intraepithelial neoplasia (CIN 1,2, or 3) in women who have sex with women as against women who have sex with men.

WOMEN'S SEXUAL HEALTH ENDOMETRIOSIS

Endometriosis may be defined as a disease characterized by the presence of functioning endometrial tissue, normally situated in the uterine cavity, outside the uterus. It is most commonly found in the pelvis, but can also be present in areas such as the abdominal cavity and the pleura (Thomas and Rock, 1997).

EPIDEMIOLOGY

Endometriosis is more commonly seen in women being investigated for infertility (21%) than among those undergoing sterilization (6%). The incidence of endometriosis in women being examined for chronic abdominal pain is 15% and, for those undergoing abdominal hysterectomy, 25% (Green Top Guidelines, 2000).

AETIOLOGY AND PATHOGENESIS

Thomas and Rock (1997) indicate that factors that increase the exposure to menstruation increase the likelihood of the disease occurring, whereas those that decrease the exposure protect against it.

Aetiological factors influencing endometriosis

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