Cervical Cancer

Cervical cancer is cancer of the cervix, the entrance to the uterus or womb. There are several forms of cervical cancer, with the most common being squamous cell carcinoma. Before this type of cervical cancer occurs, there are usually other non-cancerous abnormal cell changes. The Pap smear test is designed to detect these abnormal cells at an early stage, before they progress to cancer.

When a woman has a Pap smear test, cells are gently scraped from the surface of the cervix. The cell samples are sent to a pathology laboratory where they are examined under a microscope.

It is estimated that up to 90% of the most common form of cervical cancer can be prevented through a program of regular screening (1).

Some facts and figures

• In 2003, there were 725 cases of cervical cancer diagnosed in Australia, accounting for 1.7% of all female cancer cases (2)
• In 2003, cervical cancer accounted for 239 Australian deaths (3).
• The average risk of being diagnosed with cancer of the cervix before the age of 75 years is one in 191(4).
• In 2003, the age standardised incidence rate of cervical cancer was 7 per 100 000 women (5).

Risk factors

It appears that the main causal factor in cervical cancer is the genital human papilloma virus (HPV) or the genital wart virus. The presence of genital HPV has been found in almost all cases of cervical cancer. However, the vast majority of women with genital HPV clear the virus on their own and do not develop cervical cancer. Genital HPV is primarily transmitted through sexual contact and, therefore, the risk factors for cervical cancer are related to sexual behaviour. Risk factors include:

• Sexual activity: women who have never had sexual intercourse do not tend to develop cervical cancer
• Sexual activity with a number of different partners: multiple partners increase a woman's chance of contracting genital HPV, as does sexual intercourse with a person who has had multiple partners. However, genial HPV is so easily transmitted that even women who have only one sexual partner are still at risk.
• Smoking: although it is not known how the mechanism works, the association between smoking and cervical cancer is well-recognised.

Indigenous women

The incidence of cervical cancer is much higher in indigenous women. The age standardised mortality rate among Aboriginal and Torres Strait Islander women aged 20-69 in the 2001-2004 period was 4.7 times higher than that for other Australian women in the same age group (6).

Higher incidence and mortality rates of cervical cancer in indigenous women are a result of low screening participation rates in indigenous communities and a low compliance with follow up for cervical abnormalities (7).

Cervical cancer vaccine

Vaccines for the some strains of the human papillomavirus which cause cervical cancer are now available. Women aged 12-26 can be vaccinated for free through the National HPV Vaccination Program (8).

Cervical cancer screening: Recommendations

For Pap smear screening to be effective, tests should be done regularly. A National Cervical Screening Program has been in place across Australian Commonwealth and State Governments since 1992. It recommends that:

• Pap smears should be conducted every two years for women who have no symptoms or history of cervical problems.
• All women who have ever been sexually active should commence having Pap smears between the ages of 18-20 or one to two years after they first have sexual intercourse (which ever is the later).
• Pap smears may cease at 70 years of age for women who have had two consecutive normal Pap smears within the last five years but women over the age of 70 who have never had a Pap smear should have one .
• Women continue to have regular Pap smears, even if they have been vaccinated against genital HPV. This is because the vaccination does not provide protection from all the strains of the virus that cause cervical cancer.

Participation in screening

In the two-year period 2004-2005, 3 462 907 Australian women participated in the National Cervical Screening program. The participation rate for women aged 20- 69 years was 61% during this period (9). Queensland had one of the lowest participation rates of all states, with 58.4% of women aged 20-69 being screened (10).

Some groups of women still remain underscreened or unscreened. These women include Aboriginal and Torres Strait Islander women, women from some culturally and linguistically diverse backgrounds and women of low socioeconomic status. Similarly, some women are in fact being overscreened, that is they are being rescreened before the recommended two year screening interval, despite having a normal Pap smear result. Overscreening is an important issue as it can lead to an increase in follow-up procedures and significantly impact on the cost of the National Cervical Screening Program.

Drawbacks and debates

Although the Pap smear test is recognised as central to cervical cancer prevention, it is also acknowledged as not being infallible.  Some estimates put the number of false negatives (i.e. when a woman who actually has abnormal cells on her cervix is told her results are normal) as high as 10-20% (11). In 1994, the case O'Shea v. Sullivan and others highlighted the fact that a negative Pap smear result did not necessarily mean that no abnormal cells were present. 

It is estimated that even if every woman who is eligible regularly participated in a screening program, approximately 160 new cases of squamous cell cervical cancer would still be diagnosed each year (12). Some types of cervical cancer develop too rapidly for regular screening to spot them. However, reducing the screening interval to one year for all women would be extremely costly; it is estimated that this would increase the number of lives saved by only 1% but would cost approximately $7 million per life saved (13).

There are a number of ways in which women can improve the chances of having cervical abnormalities detected. A woman should firstly ensure that she has regular Pap smears. She needs to be aware of the possible symptoms of cervical cancer, such as unexpected bleeding and report any of these symptoms to her doctor. She should also make arrangements to be notified of the result of her Pap smear and ensure that any required follow-up treatment is carried out.

In February 1999 a Pap smear register was finally established in Queensland. The Queensland Health Pap Smear Register is a central database of Pap smears and related histology results for women in Queensland. The register will act as a back-up reminder service for women who are overdue for their regular Pap smear and as a safety net for women who require follow-up after an abnormal Pap smear. The register will also assist in monitoring participation in the cervical cancer screening program and identify groups that are being underscreened (14).

Other developments in cervical screening

A number of new technological developments in cervical screening are now available to women at an additional cost to women as add-ons to conventional Pap smear screening.  The first is liquid based cytology (eg. ThinPrep) which involves the sample being placed into a bottle of fluid and then being fixed on to a slide by a machine at a laboratory. It is claimed that liquid based cytology provides a better sample of cells for analysis, eliminating clumping and unnecessary material such as mucus and blood. In 2002, the Medical Services Advisory Committee published a report on liquid based cytology, concluding that "since there is currently insufficient evidence pertaining to liquid-based cytology for cervical screening, the MSAC recommends that public funding should not be supported at this time for this screening test" (15). As a result a woman who wishes to utilise this technology will have be charged an additional fee by the laboratory, ranging from $25-$38 dollars.

The second development is the automated examination of slides. This involves the Pap smear being analysed by an automated system and is designed to detect cell abnormalities missed by manual screening. It also involves an additional fee.

A test for HPV itself is available but as the virus is so prevalent and most women manage to clear it themselves, it is currently only recommended as a post-treatment test for those women who have received treatment for abnormal changes.

Treatment for abnormal smear

Because the Pap smear test is designed to detect pre-cancerous changes in the cervical cells a 'positive' Pap smear does not usually mean that cancer is present. Non-cancerous abnormal cell changes are classified into two levels, low and high grade lesions. Treatment options depend upon the type and severity of the abnormality detected, the woman's age and previous smear results. Some abnormalities will only require repeat Pap smears, while others will need further tests and treatments. Further tests include a colposcopy, in which a microscope-like instrument called a colposcope is used to view the cervix and vagina. During a colposcopy a biopsy may also be performed. A biopsy involves the removal of a small sample of tissue from the abnormal areas of the cervix for laboratory testing.

In the rare case that cervical cancer is detected, surgery, often followed by radiotherapy and/or chemotherapy is used to treat the cancer. The treatment and its success depends on what stage the cancer is detected at.

References

1. Coory, M. et al. Cervical Cancer and the Queensland Cervical Screening Program: Information Circular 49 Health Information Centre, Queensland Health  1999 p1
2. Australian Institute of Health and Welfare and Australasian Association of Cancer Registries (AACR). Cancer in Australia, an overview 2006 Canberra: AIHW 2006 p13
3. Australian Institute of Health and Welfare and Australasian Association of Cancer Registries. Cancer in Australia, an overview 2006 Ibid p49
4. Australian Institute of Health and Welfare and Australasian Association of Cancer Registries. Cancer in Australia, an overview 2006 Ibid p13
5. Australian Institute of Health and Welfare and Australasian Association of Cancer Registries. Cancer in Australia, an overview 2006 Ibid p41
6. Australian Institute of Health and Welfare. Cervical Screening in Australia 2004-2005. Canberra: AIHW 2007 p33
7. Coory, M et al. Cancer Among People Living In Rural and Remote Indigenous Communities in Queensland: Information Circular 54 Health Information Centre, Queensland Health 2001 p3
8. Department of Health and Ageing. Preventing Cervical Cancer http://www.health.gov.au/cervicalcancer [website] date accessed: 30th October, 2007.
9. Australian Institute of Health and Welfare. Cervical Screening in Australia 2004-2005. Ibid p5
10. Australian Institute of Health and Welfare. Cervical Screening in Australia 2004-2005. Ibid p5
11. Cannold L Cervical screening: how effective is it in preventing cancer of the cervix? Healthsharing Women Vol 5 No 5 1995 p9-12
12. Cannold L. Ibid
13. Cannold L. Ibid
14. Coory, M. et al. Cervical Cancer and the Queensland Cervical Screening Program: Information Circular 49 Ibid p1,6
15. Medical Services Advisory Committee. Liquid Based Cytology for Cervical Screening: Assessment Report Canberra: Commonwealth of Australia px

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This student factsheet is one of a series produced by Women's Health Queensland Wide. They have been developed in response to students' most frequently asked questions and reflect a range of topics examined by high school and tertiary students. It has been reviewed by our Editorial Committee. This factsheet is designed for student assignment purposes and, therefore, may not be an appropriate source of information for personal use.

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Last Modified: October 30th, 2007