The comparative effectiveness of cytology testing and HPV DNA testing

TOPICS

The comparative effectiveness of cytology testing and HPV DNA testing based primary screening pathways within a cervical screening program.

Content:

Title (front page)

Abstract

Content

Intro

1st point: Cytology testing in general (the background, purpose, impact, efficacy/effectiveness anything related to it)

2nd point: HPV testing in general (the background, purpose, impact, efficacy & efficiency and anything related to it)

3rd point: Comparison effectiveness between cytology testing and HPV testing in term of result, testing, significance, sensitivity, specificity, efficiency, efficacy, diagnostic and application.

4th point: Comparison effectiveness between cytology testing and HPV testing in term cost, impact, expertise, public wise, government wise(Australia), advantages & disadvantages

5th point: Future planning and discussion either this test can co exist or not.Which one is better as primary screening or both can co-exist together.

Conclusion

*make sure the information are scientifically relevant not literally relevant.

Reference

GENERAL PRESENTATION

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The comparative effectiveness of cytology testing and HPV DNA testing based primary screening pathways within a cervical screening program

Abstract


The objective of this research study aims at comparing two cervical cancers two screening strategies. Cytology is the existing screening program and the study aims at identifying the most effective between Cytology and HPV in the exposure of high-grade cervical disease.

Introduction

Cancer of the cervix was responsible for 275,000 mortalities worldwide in 2008 alone. Most of these were in low and medium income earning countries. It ranks third among the commonest cancer in women [7]. Cervical cancer itself occurs from the transformational zone of the cervix that is the junction between the outer squalors and the inner glandular columnar layers. These cells can change in their form, and may or may not lead to formation of cancerous growth. Routine Pap smear programs can detect these pre- cancerous growths. [2] There are two types of cervical cancer, namely the  squalors cell (responsible for 80% of cases)  and the adenocarcinoma, which is  less common, originates from the columnar layers and harder to diagnose.[6] The condition is especially associated with Human  papilloma virus (HPV)  More than 92% of squamous cell carcinoma. For instance, have had a high risk HPV DNA detected, which is sexually transmitted. [3,4] More than 100 strains of HPV exist.[6] 15 of these are classified as high risk strains, the most prevalent being type 16 & 18, which cause about 70% of cervical cancers worldwide. [10, 11]        

Prevention strategies include the primary method (health education and vaccination) and the secondary, namely screening, and early management of precancerous lesions. [8]

Cervical cancer screening has proved key in managing this condition. It not only detects potentially cancerous lesions, but also removes high- grade lesions before they progress to be invasive. 2]p343 para1. The screening itself is commonly done using the HPV test, cervical cytology (pap smear test), or a combination of the two. Visual technique using VILI  (visual inspection with Lugos Iodine) or VIA (Visual inspection with Acetic acid) is another technique that is used. Management of cancer of the cervix is dependent on its stage. Precancerous lesions are treated with cryotherapy, LEEP (loop electrosurgical excision procedure.) If there is suspicion of cancer, further tests: colposcopy and biopsy are done as to rule out false negatives. Invasive cancers are managed by confiscation, hysterectomy, and in advanced stages, radiotherapy, and chemotherapy [ ] Follow up screening varies between 3-5 years, but annually for those with CIN. [12]

The Australian National Cervical Screening program targets women within the 20-69 age brackets for cervical cancer screening. In 2004, 3,412,852 of the target population (translating to 60.6%, with a 95%CI) were screened. 14,503, most of them between 25-29 years old, were high- grade squamous intraepithelial irregularity. [5]

Screening reduces the mortality due to this carcinoma. In fact, in the low-income countries, it is one of the greatest causes of death among women. [7]Fortunately, there has been a decline in the prevalence and mortalities due to it.  In Australia, for instance, between 1991 and 2002, a drop from 329 to 227 was recorded in cancer of the cervix related deaths. [5]

On when screening should begin, the American Cancer Society recommend either from 21 years of age as the ideal, or from 3 years after the onset of per vagina intercourse. Beginning the screening later than 21 years of age exposes to a risk of late diagnosis. Evidence has shown, moreover, that screening before three year post exposure to HPV may give more false positive as cervical lesions can regress with time. Over-diagnosis would cause unnecessary treatment. Duration from the first vaginal sexual activity is the preferred marker for cytological screening initiation.

A number of factors, which are difficult to surmount, even in idealized situations, diminishes the level of sensitivity of a test; false negatives are almost unavoidable. These include small lesion size, remote lesion location, small sample acquisition, abnormally small cells and the presence of blood, pus or /and inflammation which affect the ability for the cells to be visualized. [2] Pg343 para1

First point:      

Cytology testing in general(the background, purpose, impact, efficacy/effectiveness anything related to it)
Large RCTs clearly establish that for cytology-based screening, LBC does not differ from conventional cytology in sensitivity, specificity, or relative CIN detection but may yield a lower proportion of unsatisfactory slides. Cost, overall screening strategy, and other considerations may also pertain to local decisions on which approach to use for conducting cytological screening [1], pg 6 para1

Pap test sensitivity for high-grade cervical intraepithelial neoplasia (CIN) is in the range of 70 to 80 percent. [5].This is a complex process that requires an analysis that should be used to determine the balance between these two testing is in terms of harms and benefits. For the community showing that the screening process has great benefits and a net profit at a price that is affordable to all. In regarding to the screening of women process, the issue has prominence impacts in the recent controversies in the community. In this case, policy makers are in most times often forced to make decisions on very limited evidence. Women were first invited for cervical screening after reaching the age of 25.The decision to change the right age for a screening to be done on the first time showed that a relative reduction in the invasive cervical cancer that was connected to screening had been substantially based on women between the ages of 20-34 years.

The existing women screening programs requires modifications in order to make them more effective to achieve their targeted objective. According to research conducted by International Agency for Research on Cancer (IARC)   had no details concerning dependency age for the screening process, but showed that there were no effects caused by age either the cytological screening sensitivity .Sojoum distribution on time the disease needed to be considered. There was no evidence that women under the age of 35 were close to risk in developing tumors. After an analysis, it was made clear that there existed a risk reduction to five years after a normal result, which was greater in older age groups.

Screening in women who are aged 20-24 has no records on the cervical cancer under the age of 35 years.

 Since its introduction, Papanicolaou (Pap) smear screening has been able to get transformed cervical cancer from a fatal disease into a rare condition. Despite the considerable success of this cytological screening, Pap smears have not, as it was first hoped, reduced incidence on a large scale. The principal reasons are related to the difficulties in ensuring optimum coverage of the population to be screened and in maximizing women’s adherence: the success of screening depends on strict compliance with the calendar from 25 to65 years of age. In one-third of cases, invasive cancers are found in women who undergo regular screening, because Pap smears are insufficiently sensitive [17]

Second point:
HPV testing in general (the background, purpose, impact, efficacy & efficiency and anything related to it)

HPV virus is very common, where there are almost 40 types and HPV and can cause infections in the human genitals or the sex organs in men and women. HVP viruses can also cause infections in the human mouth or throat. These types of viruses are common to a point   that they get it at some time in their entire lives. On the other hand, it is important to note that HVP does not cause any kind of symptoms and it is hard to tell if one has these viruses.


Human Pappilloma virus exists as norm flora on the human mucus membrane and skin. In most cases, it is anon pathogenic. It can causes carcinoma of the penis, cervix, or pharynx and anus. [15]

   Human Papillomavirus

HPV is the main cause of cervical cancer.[3] Other predisposing factors associated with cervical cancer etiology are smoking, involving in sexual activity before the age of 17 years, prolonged use of certain medication and immune-suppression. [13, 14]

The eventual discovery of HPV as the key cause of CIN happened after a long course of studies. The query of an infection as cervical cancer’s etiology drew interest after an Italian report was published in the 19th century (18). Though many organisms were suspected, the Herpes Simplex virus type two (HSV 2) was for a long time thought to be the most likely cause.  This in addition, was ruled out [19, 20, and 21] Research done by Herald Zur Hausen showed close link between papilloma viruses and squamous cell carcinoma in cottontail rabbits [21]? Further work identified viral antigens & particles in cervical cancer samples [22] The initial experiments utilized HPV DNA from skin warts, but these did not match the characteristics as in the causative agent in cervical cancer. (23, 24) After a series of purification of HPV DNA, a breakthrough was found in identification of five HPV sub-types. More strains