Cervical cancer is the ninth leading cause of female cancer deaths in Hong Kong. In 2011, 391 new cases of cervical cancer were diagnosed and the age-standardized incidence rate was 7.2 per 100,000 standard populations. In 2012, 133 women died from this cancer, accounting for 2.5% of female cancer deaths. The age-standardized death rate of cervical cancer was 2.1 per 100,000 standard populations. Human papillomavirus (HPV) infection is an established cause of cervical cancer. HPV vaccines offer more than 70% protection for women against HPV types 16 and 18 infections and their related cervical precancerous lesions and cervical cancer. As there are usually no symptoms in high-risk HPV infection, it is often diagnosed at a late stage. Regular cervical smears can offer early detection of pathological changes and pre-cancerous stage for a timely medical treatment to prevent progression to cervical cancer. The Cervical Screening Programme (CSP) of Department of Health (DH) was launched on 8 March 2004. It is a voluntary program with the objectives to increase the population coverage of cervical screening among women and to reduce the incidence and mortality of cervical cancer in Hong Kong. Women participating in the programme are encouraged to have cervical smears in the medical centres of their own choices and to provide their cervical smear information through their health care providers to the central registry of the CSP - The Cervical Screening Information System (CSIS). As at 31 December 2013, 491,674 women have registered with CSP. When DH implemented CSP in March 2004, a report was published in the same year showing evidence that an organized screening compared with the opportunistic screening could substantially increase benefits and reduce costs. Another local study conducted early this year supported by the Health Services Research Fund also highlighted the importance and urgency in enhancing the current screening protocol. It is of public health interests to study and compare the programme outcomes with countries like Finland, Australia, UK and Japan where different policy was adopted for the prevention of cervical cancer. Information gathered from research papers on epidemiological studies has been collected and analyzed on population benefit (outcome, access, disparities), cost (cost benefit, efficiency, cost containment), equity, feasibility and constituency perspectives in formulation of the policy alternatives. In conclusion, strengthening what is already in place with better allocative efficiency could protect the female population against cervical cancer. From the education perspective, emphasis on the risk of HPV infection in the sex education curriculum would raise the awareness on the precaution of HPV infections amongst young females. Additionally, vaccination at the age of 12 can provide protection against most types of HPV. It is strongly recommended that a cervical screening and HPV co-testing strategy at a triennial interval could provide the best cost and benefit effectiveness. Together they can enhance protection coverage of women at 12 through immunization and from 25 - 64 through active population screening. The ultimate objectives to reduce incidence, mortality and increase coverage could be achieved. / published_or_final_version / Public Health / Master / Master of Public Health

This dissertation explores a diagnostic image analysis framework using multispectral digital colposcopy for real-time in vivo detection of cervical cancer. In the first part of the dissertation, the clinical feasibility of a previously developed multispectral digital colposcope (MDC) is demonstrated using a hamster cheek pouch model of carcinogenesis. Various studies on MDC applications to cervical cancer detection in human subjects are then presented. First, an automated diagnostic image analysis algorithm for cervical cancer using white light reflectance images is presented. The algorithm can identify pre-neoplastic tissue areas from an entire cervix based on intensity changes feature in the reflectance images induced by acetic acid treatment. Then, the information about tissue type is incorporated into the diagnostic image analysis framework. For this purpose, a Markov Random Field (MRF) model is adopted and the results are discussed. One of the practical difficulties of utilizing a MRF model in unpolarized white light reflectance imaging is the specular reflection problem since the effect of specular reflection extends into surrounding tissue areas. Through the use of cross polarized imaging, the effects of specular reflection reduced and the ability to segment images based on tissue types is enhanced, leading to better diagnostic performance. The diagnostic performance of polarized imaging is compared to that of unpolarized imaging. In order to assess the performance of the proposed approach, a gold standard for the entire cervical image is constructed using histopathology results from a whole cervix specimen. The results presented in this dissertation indicate that an automated diagnostic image analysis framework for early detection of cervical cancer has the potential to be clinically applied as a low cost alternative screening technique in developing countries. Advances in imaging technology as well as in image analysis algorithms will continue to reduce the cost of diagnostic imaging systems and improve the imaging and diagnostic capability, leading to an inexpensive, real-time, minimally-invasive alternative to conventional screening techniques for early detection of cervical cancer in developing countries. / text

published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Background: Human papillomavirus (HPV) DNA test is more sensitive and can detect more high-grade cervical intraepithelial lesions than cytology test in cervical cancer screening. There are studies confirming HPV test being more effective in cervical cancer screening by detecting the persistence of HPV infection that could lead to cancer. However, the costs associated with a HPV test is higher than a cytology test. Moreover, HPV test is less specific which could subject more women to further triage tests or unnecessary invasive diagnostic procedures. Therefore healthcare costs could possibly increase if primary HPV screening is to be adopted. Study objective: The aim of the study is to systematically review the cost-effectiveness of primary HPV testing in cervical cancer screening Method: Electronic search was performed in three biomedical databases (PubMed, Medline, Cochrane Library) and one economic evaluation database to identify relevant studies. Studies were selected according to the explicit inclusion and exclusion criteria defined. Only those studies carried out in high-income countries were included so that result could be better applied to Hong Kong. Results: A total of 19 studies were included in this systematic review. Cytology-only method is generally not cost-effective. To be cost-effective, it has to be performed in a longer screening interval which would reduce not only the screening costs but also a reduction in the health outcomes. Among the different options in HPV-based primary screening, HPV testing with cytology triage is the most cost-effective strategy in many of the studies. Combined HPV/cytology co-screening could achieve the biggest health benefit but is also most costly. HPV-based screening is more cost-effective for those >30 years of age and is usually less cost-effective if applied to young women. From the result in sensitivity analysis, HPV-based screening is sensitive to an increase in the costs of the HPV test, a low HPV test sensitivity and a low screening compliance rate. Conclusion: Primary HPV screening is cost-effective and generally performs better than cytology screening. The result of this systematic review guides the future direction of developing an optimal cervical screening strategy in Hong Kong. Local context has to be considered when examining the cost-effectiveness of primary HPV testing for cervical screening. Good quality local epidemiological data on HPV infection and cervical cancer and screening would be required to aid future research on the application of HPV test for cervical cancer screening in Hong Kong. / published_or_final_version / Public Health / Master / Master of Public Health

In cervical screening programmes, Papanicolaou test (Pap test) is the key screening tool. However Pap test is difficult to implement in low-resource region. Introduction of an economic, cost-effective and less skill demanding equipment is hence a potential direction of advance in cervical screening methodology. 　　Cervical carcinogenesis involves genetic instability which leads to chromosomal aneuploidy. Evaluation of aneuploidy may hence provide information for identifying cancer and precursor cells. An automated DNA-image-cytometry system (DNA-imager) capable of quantitating the DNA content of cells has recently been developed. 　　To evaluate the efficacy of DNA-imager in cervical cancer screening, a total of 483 residual ThinPrep liquid-based cytology (LBC) samples after diagnosis were retrieved and evaluated by the DNA-imager. The high risk human papillomavirus (HPV) status of the atypical squamous cells of undetermined significance (ASC-US) samples has been tested as a parallel study. According to established criteria, 423 out of the 483 samples were satisfactory for downstream analysis. The samples were designated “Normal”, “Suspicious” or “Abnormal” according to their DNA aneuploidy and proliferation activity. 　　Significantly more high grade lesion samples (HSIL and SCC) were designated as “Abnormal” by DNA-imager than were lower grade lesion samples (Negative, ASC-US, AGC, ASC-H, and LSIL) (94.19% vs 51.04%, p<0.0001). For detecting ≥HSIL, DNA-imager achieved high sensitivity and specificity (94.19% and 48.96%) using “Abnormal” as cut off. Adopting a more stringent definition of “Suspicious” or “Abnormal” would increase the sensitivity to 100% but decreased the specificity to 24.33%. 　　 　　Regarding ASC-US triage, DNA-imager achieved a sensitivity and specificity of 80.00% and 71.29% respectively when “Abnormal” was used as test positive to predict cases with ≥HSIL follow-up in the next two year. The sensitivity increased but the specificity decreased to 90.00% and 34.65% respectively if “Suspicious or above” was used as indicator of undesirable follow-up. HR-HPV test, on the other hand, was able to identify all cases with ≥HSIL upon follow-up (sensitivity = 100%) but the specificity was only 15.84%. Among these ASC-US sample, test positivity of the two tests showed poor concordance with each other (Cohen’s κ = 0.062 and 0.074 respectively for “Suspicious or above” or “Abnormal”, respectively). 　　Our findings suggested that DNA-imager may be a useful tool for automated primary screening of cervical cancer 3 / published_or_final_version / Pathology / Master / Master of Medical Sciences

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Not available / text

published_or_final_version / Community Medicine / Master / Master of Public Health

published_or_final_version / Nursing Studies / Master / Master of Nursing in Advanced Practice

published_or_final_version / Public Health / Master / Master of Public Health