07 CERVICAL CANCER SCREENING

What is cervical cancer?
Cervical cancer is cancer of the cervix (the opening or neck of the womb). The cervix is covered by a thin layer of tissue consisting of cells. These cells can undergo changes over time, and may eventually turn cancerous. It can take up to several years for cervical cancer to develop, and early cell changes that occur before cancer (known as pre-cancer, dysplasia, or cervical intraepithelial neoplasia) can be detected by screening. Early treatment of these abnormal cell changes can prevent cervical cancer.

Cervical cancer is the 10th most common cancer affecting women in Singapore1. Most cervical cancer is caused by infection of the cervix with a virus known as human papilloma virus (HPV). HPV is very common, and most women who are sexually active will get a HPV infection at some point in life. It is found on the genitals, but also fingers, hands, and mouth, hence can be passed by any kind of sexual activity (including skin-to-skin contact).

There are many types of HPV, but “high-risk types” may cause cancer, most commonly of the cervix, but rarely also of the vagina, vulva and anus (back passage). Most HPV infections will go away spontaneously, and often causes no symptoms. In those women where HPV persists, it may cause abnormal cell changes, which in turn can become cancer.

Cervical cancer can present with:

  • Abnormal vaginal bleeding between periods, after intercourse, or after menopause
  • Abnormal vaginal discharge or pain

However, many women have no symptoms, even in the ‘pre-cancer’ phase. It is therefore important to see your doctor for regular cervical cancer screening, but especially if you experience any of the above.

What is cervical cancer screening?
Cervical cancer screening consists of a Pap smear test, and in some women, testing for HPV as well. There is now a HPV vaccine available, protecting against 7 “high-risk types” of HPV, and 2 “low-risk types” that cause genital warts.

Pap smear test - Sample tested for presence of abnormal cells
HPV test - Sample tested for presence of “high-risk types” of HPV

The screening process is quick and simple. A device called a speculum is gently inserted into the vagina to examine the neck of the womb (cervix). A gentle brush is used to obtain cells from the cervix and sent for testing. Results are received within 2 weeks of the test.

Who should be screened?
If you have never had sexual intercourse, you do not need a Pap smear test. However, if you experience abnormal vaginal discharge, you should still consult your doctor for advice.

Women aged 25-69 years, who have had sexual intercourse before (male or female partners), are recommended to go for a Pap smear test at least once every 3 years. Between 30-69 years of age, a HPV test can be done once every 5 years. After the age of 69, you can stop cervical screening if your previous tests have been normal. Smear tests can be considered earlier or more frequently if there are risk factors that may increase your risk of cervical cancer such as:

  • Early age of sexual activity
  • Multiple sexual partners
  • Weaker immune system
  • Personal history of cervical intraepithelial neoplasia (pre-cancer cell changes) on Pap smear

It is important to continue regular Pap smear tests even after HPV vaccination.

If early abnormal cell changes or ‘high-risk’ HPV types are detected, you may need further examination of the cervix under magnification by colposcopy. This can be arranged with our gynaecologists.

What is colposcopy?
Colposcopy is a closer examination of the genital tract consisting of the vagina, vulva, and cervix (neck of the womb), under magnification. It is a test done to determine if there are any abnormal cell changes (known as pre-cancer, dysplasia, or cervical intraepithelial neoplasia (CIN) and how serious they are. Rarely, genital tract cancer may be detected.

Colposcopy is usually performed in the outpatient setting, and is carried out in a similar way to cervical screening.

A specialist gynaecologist will insert a device called a speculum gently into the vagina, and look at the cervix using a machine with magnifying lens and light (colposcope). Application of a vinegar and brown staining solution is then applied, in order to identify abnormal areas. This examination is painless and not harmful, but if you feel discomfort during the process, tell your doctor and adjustments can be made to make you more comfortable. Sometimes, a small sample will be taken from abnormal areas identified, known as a biopsy, to check for early cancer changes.

If abnormal cell changes are confirmed, treatment may be offered at the same setting, or later, to remove the cells. There are various types of treatment, most commonly:

  • LEEP (Loop Electrosurgical Excision Procedure) - use of a small electric wire loop to remove the area of abnormal cells
  • Laser ablation - laser treatment to destroy abnormal cells

The type of treatment recommended depends on various factors, and should be discussed closely with your specialist. It is usually performed in the outpatient clinic, at the same time as a colposcopy. However, laser treatment may need to be done as a day surgery procedure in an operating theatre.

What are the risks?
Colposcopy examination itself carries little risks, besides minor discomfort. If a biopsy is taken, some bleeding can be expected, which is normal and may last a few days.

Treatment, in particular LEEP, will carry some risks such as:

  • Mild vaginal bleeding - this is normal and can last up to 2-3 weeks
  • Infection - antibiotics are usually given to prevent this
  • Future pregnancy risks - women who get pregnant after LEEP may be at a small increased risk of preterm delivery2, and the risk increases with a larger treatment area

How long do the results take?
If a small sample is taken at colposcopy, or a LEEP is done, results are usually available in 1-2 weeks. Depending on the results, further treatment will be discussed with your doctor.

References:

  1. Singapore Cancer Registry, Annual Registry Report 2015
  2. NHS Cervical Screening Programme, Colposcopy and Programme Management, Third Edition March 2016
  3. Castanon A, Landy R, Brocklehurst P, Evans H, Peebles D, Singh N, Walker P, Patnick J, Sasieni P; PaCT Study Group. Risk of preterm delivery with increasing depth of excision for cervical intraepithelial neoplasia in England: nested case-control study. BMJ, 2014, 349:g6223. doi: 10.1136/bmj.g6223.