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Woolloomooloo, Australia

Nair-Shalliker V.,Cancer Epidemiology Research Unit | Armstrong B.K.,University of Sydney | Fenech M.,CSIRO
Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis | Year: 2012

Vitamin D is a secosteroid best known for its role in maintaining bone and muscle health. Adequate levels of vitamin D may also be beneficial in maintaining DNA integrity. This role of vitamin D can be divided into a primary function that prevents damage from DNA and a secondary function that regulates the growth rate of cells. The potential for vitamin D to reduce oxidative damage to DNA in a human has been suggested by clinical trial where vitamin D supplementation reduced 8-hydroxy-2'-deoxyguanosine, a marker of oxidative damage, in colorectal epithelial crypt cells. Studies in animal models and in different cell types have also shown marked reduction in oxidative stress damage and chromosomal aberrations, prevention of telomere shortening and inhibition of telomerase activity following treatment with vitamin D. The secondary function of vitamin D in preventing DNA damage includes regulation of the poly-ADP-ribose polymerase activity in the DNA damage response pathway involved in the detection of DNA lesions. It is also able to regulate the cell cycle to prevent the propagation of damaged DNA, and to regulate apoptosis to promote cell death. Vitamin D may contribute to prevention of human colorectal cancer, though there is little evidence to suggest that prevention of DNA damage mediates this effect, if real. Very limited human data mean that the intake of vitamin D required to minimise DNA damage remains uncertain. © 2012 Elsevier B.V. Source

Canfell K.,Cancer Epidemiology Research Unit | Canfell K.,University of Sydney | Chesson H.,Centers for Disease Control and Prevention | Kulasingam S.L.,University of Minnesota | And 3 more authors.
Vaccine | Year: 2012

Over the last 5 years, prophylactic vaccination against human papillomavirus (HPV) in pre-adolescent females has been introduced in most developed countries, supported by modeled evaluations that have almost universally found vaccination of pre-adolescent females to be cost-effective. Studies to date suggest that vaccination of pre-adolescent males may also be cost-effective at a cost per vaccinated individual of ~US$400-500 if vaccination coverage in females cannot be increased above ~50%; but if it is possible, increasing coverage in females appears to be a better return on investment. Comparative evaluation of the quadrivalent (HPV16,18,6,11) and bivalent (HPV16,18) vaccines centers around the potential trade-off between protection against anogenital warts and vaccine-specific levels of cross-protection against infections not targeted by the vaccines. Future evaluations will also need to consider the cost-effectiveness of a next generation nonavalent vaccine designed to protect against ~90% of cervical cancers. The timing of the effect of vaccination on cervical screening programs will be country-specific and will depend on vaccination catch-up age range and coverage and the age at which screening starts. Initial evaluations suggest that if screening remains unchanged, it will be less cost-effective in vaccinated compared to unvaccinated women but, in the context of current vaccines, will remain an important prevention method. Comprehensive evaluation of new approaches to screening will need to consider the population-level effects of vaccination over time. New screening strategies of particular interest include delaying the start age of screening, increasing the screening interval and switching to primary HPV screening. Future evaluations of screening will also need to focus on the effects of disparities in screening and vaccination uptake, the potential effects of vaccination on screening participation, and the effects of imperfect compliance with screening recommendations. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012. © 2012 Elsevier Ltd. Source

Canfell K.,Cancer Epidemiology Research Unit | Canfell K.,University of Sydney
Sexual Health | Year: 2010

Epidemiologic and economic evaluation using simulation modelling can support complex policy decisions, and is an important tool in predicting the future interaction between human papillomavirus vaccination and cervical screening. Several categories of screening program evaluation are of interest, including: (1) changes to screening considered over the short term, over which the effects of vaccination should be confined to the youngest age groups (30 years old); (2) the medium and long-term effect of vaccination on the screening program; and (3) changes to screening in context of vaccination. This review considers some of the policy questions in each category and discusses the modelling implications, with particular focus on the Australian context. © CSIRO 2010. Source

Smith M.A.,Cancer Epidemiology Research Unit | Lew J.-B.,Cancer Epidemiology Research Unit | Walker R.J.,Cancer Epidemiology Research Unit | Brotherton J.M.L.,Registries Victorian Cytology Service | And 4 more authors.
Vaccine | Year: 2011

Australia implemented a National HPV Vaccination Program in 2007, with routine vaccination of 12-13 year old females and catch-up in females aged 13-26. years to 2009. The aim of this study was to estimate the impact of the current female-only national vaccination program on males, and then to estimate the incremental benefits to males from being included in the program. We used preliminary data to estimate vaccination coverage in females. We then fitted a dynamic model of sexual behaviour and HPV transmission in Australia to local data on female pre-vaccination age-specific HPV prevalence, predicted the corresponding pre-vaccination prevalence in males due to heterosexual transmission, and modelled the short and long term impact of female-only versus female-and-male vaccination programs. The estimated 3-dose female coverage rates were 78% (range 70-80%) for ongoing coverage in 12-13 year old girls; and from 74% (range 70-80%) in 14 year olds, to 25% (range 15-35%) for women aged 26. years old in 2007. The median estimate for age-standardised pre-vaccination HPV 16 prevalence in females and males aged 15-59. years was 3.2% (95% range: 2.4-4.1%) and 3.1% (95% range: 2.2-4.2%), respectively. The current program in females is predicted to result in a 68% reduction in male HPV 16 infections by 2050, leading to an estimated long term reduction of 14% in rates of cancers of the head, neck and anogenital area. The estimated proportion of the maximum possible vaccine-conferred benefit to males from a female-and-male program which will be achieved by female-only vaccination is 73% (range in probabilistic sensitivity analysis: 53-78%). In conclusion, up to three-quarters of the maximum possible vaccination-conferred benefit to males due to reduced heterosexual transmission will be achieved by the existing female-only program. © 2011 Elsevier Ltd. Source

Kahn C.,Cancer Epidemiology Research Unit | Simonella L.,Cancer Epidemiology Research Unit | Sywak M.,University of Sydney | Boyages S.,Clinical Education and Training Institute NSW | And 2 more authors.
Cancer Causes and Control | Year: 2012

Background: Over the past few decades, an increase in the incidence of thyroid cancer has been recorded in many countries around the world including Australia. Heightened medical surveillance and increased technological sensitivity could be contributing to greater detection of asymptomatic disease. Objectives: To describe the pathways to diagnosis of thyroid cancer for a cohort of newly diagnosed patients in New South Wales (NSW), Australia, and compare these pathways by age, sex, place of residence, ethnic background, medical insurance status, and disease characteristics. Methods: A total of 452 newly diagnosed cases of thyroid cancer were recruited through the population-based NSW Central Cancer Registry. Participants completed a questionnaire and diary of doctor visits and investigations that led to their diagnosis. Tumor characteristics were obtained from pathology reports. Results: Forty percent of patients initially presented to their doctor with a lump or symptom specific to thyroid cancer and 60% had their cancer detected incidentally during a medical encounter. Men were more likely than women to be diagnosed after imaging for another health concern versus reporting a thyroid lump or symptom (p = 0.001). Thyroid cancer diagnosis after imaging for another health concern increased with age (p = 0.023), and larger tumors were less likely to be diagnosed after treatment for a benign thyroid disease (p = 0.040). Conclusion: As the majority of participants had incidental diagnoses, the reported incidence of thyroid cancer is likely to be influenced by diagnostic technology and medical surveillance practices. This, however, probably only partly explains the observed rise in the incidence of thyroid cancer in NSW. © 2011 Springer Science+Business Media B.V. Source

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