Since the 1950’s, pap smear tests have been widely used in western countries to detect cervical cancer. However, there are some disadvantages relating to the test. Other forms of detection though including liquid base cytology, HPV DNA test and optoelectronic cervical screening have proven to be either costly, ineffective or impractical in application. For these reasons pap smears will continue to be used for some time to come.
Pap smear is a procedure or tool to examine cells collected from the cervix (the lower part of the uterus). The major objective of this test is to detect cancer or abnormal cells which might become cancer. It can also find non cancerous conditions such as infections and inflammation (National Cancer Institute (NCI), 2009, p.1) According to Women’s Health Queensland Wide (WHQW) (2007, p.1) cervical cancer is cancer of the cervix. There quite a few forms of cervical cancer but squamous cell (thin flat cells that form the surface of the cervix) carcinoma are the most common one. Usually other non cancerous abnormal cell changes occur before this type of cervical cancer take place however these abnormal cells at early stage can be found with a pap smear test.
The pap smear test is named after Dr Papanicolaou who discovered in 1928 that cells in the cervix change in appearance before becoming cancerous. Following this pap smears became a screening tool to find early abnormal cells and used to examine changes in the cervix (Australian Government Department of Health and Ageing (AGDHA), 2006, p.1).
Most industrialized countries use pap smear as a foundation of cervical screening tool. It has been widely used in the United States since 1950 (Waxman ,2008, p.1 ) and became available to Australian women in 1960 (Queensland Health Pap Smear Register, 2008, p.1). Furthermore, in 1991 pap smears became the primary cervical screening tool to reduce illness and mortality from cervical cancer (AGDHA, 2009, p.1).
The causes of cervical cancer are well understood. Genital human papillomaviruses (HPV) are the major contributory factor in cervical cancer. In facts in almost all cases of cervical cancer the presence of genital HPV has been found (Medical News Today, 2008, p.3). HPV is usually cleared by the body’s immune system; however abnormalities of the cervix may develop in some women who have constant infections (AGDHA, 2006, p.2). HPV is a sexually transmitted infection through sexual contact therefore the risk factors for cervical cancer are related to sexual behavior, which includes sexual activity with a number of different partners, becoming sexually active at a young age, sexual intercourse with a person who has multiple partners or intercourse with a HPV infected person (NCI, 2009, p.3)
Pap smear is a low cost, quick and simple screening tool for cervical cancer. In Australia, pap smear is covered by Medicare and there is no extra fee for the test (AGDHA, 2009, p.1). Having pap smear regularly every two years can prevent the most common form of cervical cancer in up to 90 percent of cases (AGDHA, 2006, p.10) Like all other screening devices, the pap smear has limitations and sometimes it will not discover early cell changes. This is because the smear did not hold enough abnormal cells and because of possible difficulties in interpretation (AGDHA, 2006, p.2).
The National Cervical Screening Program (NCSP) is the current way of cervical cancer control in Australia which uses pap smear as the screening tool. It has been a tremendously successful screening device in detecting and decreasing incidence and death related with cervical cancer, which is one of the most preventable and curable of all cancers. In Australian women it is the eighteenth most common cause of cancer mortality. Nevertheless, it has dropped from eighth place since the introduction of the NCSP using pap smear tests (AGDHA, 2009, p.1). According to Better Health Channel, (2008 p.1 ) regular pap smears in Australia save more than 1,200 woman per year from cervical cancer. It is also stated that having Pap smear is the best protection against cervical cancer. For example, the number of new cases of cervical cancer in Australia has continuously decreased and there were 734 cases in 2005 compared with 1092 cases detection in 1991. Furthermore, the statistics showed the mortality rate from cervical cancer has more than halved since the start of the pap smear program from 4.0 deaths per 100,000 women in 1991 to 1.9 deaths per 100,000 women in 2006 (AGDHA, 2009, p.2).
Although the Pap smear test is recognized as central to prevent cervical cancer it is also not always 100 percent accurate. The first disadvantage of Pap smear is false negative and false positive results. These results can happen and it can be upsetting and confusing for women (WHQW), 2007, p.2). A false negative is when a patient is told that the cells in the cervix are normal but in fact there are abnormal cells present on the cervix. A false positive is when a patient is told that abnormal cells are present in the cervix but in reality the cells are actually normal. False negatives delay the detection and treatment of unhealthy cells of the cervix however having regular pap tests boosts a women’s opportunity of finding any problems (NCI, 2009, p.4).
Another disadvantage is the abnormalities. Pap smear test results can be abnormal, which means cells on the surface of the cervix sometimes show abnormalities but are rarely cancerous. For example, in 2007 the National Cervical Screening Program in Australia detected 14,466 women in the target age group 20- 69 years with high-grade abnormalities (AGDHA, 2009, p.2). Also, about 55 millions pap test are performed each year in United states and from that number 3.5 million have abnormalities and must attend a compulsory medical follow- up (NCI, 2009, p.2).However, according to Better Health Channel, (2009,b, p.4 ) of the small number of pap tests that gave an abnormal result almost all of them are not due to cervical cancer but common infections or conditions which clear up naturally .
In addition, a pap smear test is invasive and unpleasant. Every woman who undergoes a pap smear test will verify that it is unpleasant. This is the reason why women easily forget to have pap smear (Country Women’s Association of New South Wales, 2006, p.27). Also some women find pap smear test embarrassing and humiliating and for this reason women wish to have longer intervals between smears and fewer smears. in their lifetime. (Dickinson, 200, p14)
A number of new technological developments in cervical cancer are now available to woman with extra cost. Currently there are a number of new cervical screening technologies including Liquid Based Cytology (LBC), HPV DNA testing and Optoelectronic cervical screening (AGDHA, 2008, p.2).
The first new technological development is Liquid Based Cytology. LBC is a technique of cervical sample preparation for examination. The samples can be collected in two ways, either directly from collection tools or rinsed in preservative fluid from pap smear collection tools (AGDHG, 2008, p.2). This procedure result gave a capability rate of LBC as a cervical screening tool that is higher than Pap smear test (Pui & Fock, 2006, p.1). However in Singapore a literature review was conducted to compare the sensitivity, specificity and cost implications with Pap smear test and the result showed that LBC gives a higher rate of false negatives, at a rate of 0.38 percent. Also, LBC has higher associated costs and it was concluded that it is not cost effective to replace Pap smears with LBC tests in Singapore (Pui & Fock, 2006, p.1). It is also claimed that LBC provides a better illustration of cells for examination, eliminating clumping and useless material such as mucus and blood. However in 2002, the Medical Services Advisory Committee (MSAC) in Australia reviewed this technology and found that there was insufficient evidence on the performance of LBC to facilitate effective comparisons to pap smears (AGDHA, 2008, p.1). Also in the same year a report on LBC was published by the MSAC stating that public funding should not be supported due to lack of evidence pertaining to liquid based cytology for cervical screening (cited in Women’s Health Queensland Wide, 2007, p.18).
Since the majority of cervical cancers are associated with persistent infection with human papillomaviruses (HPV), another new technology screening tool for cervical cancer is the HPV DNA test. This test can detect the presence of HPV infection in cervical cells (AGDHA, 2008, p.2). The Danish Cancer Society documented that a single HPV test is superior at detecting older women at risk for cervical cancer to pap smears (Medical News Today, 2006,
p.3).The study found that for women who are 40 and older, an HPV test is a more effective way to screen for potential cancer. Also, it has been proved that an HPV test is more sensitive than a pap smear but it has a moderately lower specificity which can not discover truly negative cases (Anttila, Hkama, Talonen, Nieminen, 2006, p.3). Though it is recognized that the HPV test is superior to pap smear tests as a screening tools its true benefits are still unidentified until a large enough study which compares it directly to the standard screening test, is carried out (MNT, 2008, p.1).For this reasons, the MSAC in Australia reviewed HPV testing for cervical screening in 2003 and decided that at that time there was insufficient evidence to support the use of the technology as a screening procedure (AGDHA, 2008, p.2).
Cohort analyses and comparison show that HPV DNA test highlight sensitivity for detection underlying high grade lesions more effectively than pap test. It has another advantage in that it can be performed on self. The clinically effectiveness of the HPV DNA testing is being further reviewed as it can be used in combination with pap test or as a stand alone test in primary screening as a test of healing. For example in United State of America HPV DNA testing was approved recently for use with the pap test for women 30 years and over (Garland, MS,200, p.5)
Optoelectronic cervical screening is the third new cervical screening technology which is a technique of the detection of the cervix abnormalities using an optoelectronic sensor to highlight abnormal areas of the cervix. This device is on the Australian Register of Therapeutic Goods in Australia however it is not suggested for use in cervical screening as a result of its low specificity (a high level of false positive), which increases women’s anxiety and unnecessary colposcopy investigations. (AGDHA, 2008, p.2).
In conclusion, pap smear plays a vital role as a cervical cancer screening tool and has successfully decreased the mortality rate from cervical cancer. Like any other screening tool Pap smear has advantages and disadvantages and it is not always 100 percent accurate, however before any new technology is recommended for use as the screening tools there must be sufficient evidence for its practicality, effectiveness and cost effectiveness. Pap smears will continue to be used as the primary method for screening until there is sufficient evidence indicating the superiority of new cervical screening technologies.
Reference List
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