The beginning of the end for cervical cancer?

Awareness and acceptance of human papillomavirus vaccination among health sciences students in Malaysia

The major cause of cervical cancer is human papillomavirus (HPV) for which vaccination is available. The success HPV vaccination programme largely depend on the degree of knowledge of the healthcare providers who can recommend to the public. Health sciences students as future healthcare providers play a major role in HPV vaccination initiatives. The objective of this study was to evaluate the knowledge, attitude, practice and to find out the willingness to pay for HPV vaccination among the health sciences students in a private university. The cross-sectional study was conducted among the university students studying health sciences program using a validated questionnaire to measure their awareness and acceptance of HPV vaccination. The students demonstrated moderate knowledge about HPV infection and vaccination with mean knowledge scores of 9.3 out of 17. Students were showing positive attitude towards HPV vaccination with mean scores of 3.80 out of 5. However, low HPV vaccination uptake rate was reported among the students. Most of the students were willing to recommend HPV vaccine. The participants felt that the cost is the major barrier towards HPV vaccination and they felt the government should cover the cost of vaccination for all. The results of this study may be helpful in establishing educational policies on cervical cancer-related topics in the universities.

Overall efficacy of HPV-16/18 AS04-adjuvanted vaccine against grade 3 or greater cervical intraepithelial neoplasia: 4-year end-of-study analysis of the randomised, double-blind PATRICIA trial

BACKGROUND

Cervical intraepithelial neoplasia grade 2 or greater (CIN2+) is the surrogate endpoint used in licensure trials of human papillomavirus (HPV) vaccines. Vaccine efficacy against CIN3+, the immediate precursor to invasive cervical cancer, is more difficult to measure because of its lower incidence, but provides the most stringent evidence of potential cancer prevention. We report vaccine efficacy against CIN3+ and adenocarcinoma in situ (AIS) in the end-of-study analysis of PATRICIA (PApilloma TRIal against Cancer In young Adults).

METHODS

Healthy women aged 15-25 years with no more than six lifetime sexual partners were included in PATRICIA, irrespective of their baseline HPV DNA status, HPV-16 or HPV-18 serostatus, or cytology. Women were randomly assigned (1:1) to receive an HPV-16/18 AS04-adjuvanted vaccine or a control hepatitis A vaccine via an internet-based central randomisation system using a minimisation algorithm to account for age ranges and study sites. The patients and study investigators were masked to allocated vaccine. The primary endpoint of PATRICIA has been reported previously. In the present end-of-study analysis, we focus on CIN3+ and AIS in the populations of most clinical interest, the total vaccinated cohort (TVC) and the TVC-naive. The TVC comprised all women who received at least one vaccine dose, approximating catch-up populations and including sexually active women (vaccine n=9319; control=9325). The TVC-naive comprised women with no evidence of oncogenic HPV infection at baseline, approximating early adolescent HPV exposure (vaccine n=5824; control=5820). This study is registered with ClinicalTrials.gov, number NCT00122681.

FINDINGS

Vaccine efficacy against CIN3+ associated with HPV-16/18 was 100% (95% CI 85·5-100) in the TVC-naive and 45·7% (22·9-62·2) in the TVC. Vaccine efficacy against all CIN3+ (irrespective of HPV type in the lesion and including lesions with no HPV DNA detected) was 93·2% (78·9-98·7) in the TVC-naive and 45·6% (28·8-58·7) in the TVC. In the TVC-naive, vaccine efficacy against all CIN3+ was higher than 90% in all age groups. In the TVC, vaccine efficacy against all CIN3+ and CIN3+ associated with HPV-16/18 was highest in the 15-17 year age group and progressively decreased in the 18-20 year and 21-25 year age groups. Vaccine efficacy against all AIS was 100% (31·0-100) and 76·9% (16·0-95·8) in the TVC-naive and TVC, respectively. Serious adverse events occurred in 835 (9·0%) and 829 (8·9%) women in the vaccine and control groups, respectively; only ten events (0·1%) and five events (0·1%), respectively, were considered to be related to vaccination.

INTERPRETATION

PATRICIA end-of-study results show excellent vaccine efficacy against CIN3+ and AIS irrespective of HPV DNA in the lesion. Population-based vaccination that incorporates the HPV-16/18 vaccine and high coverage of early adolescents might have the potential to substantially reduce the incidence of cervical cancer.

FUNDING

GlaxoSmithKline Biologicals.

Population fraction of cervical neoplasia attributable to high-risk human papillomaviruses

AIMS

The efficacy of human papillomavirus (HPV) type 16 and 18 vaccines against cervical intraepithelial neoplasia grade II (CIN2+) has been verified, but the active follow-up of studies with invasive cervical cancer or cervical intraepithelial neoplasia grade III (CIN3) as primary end points are ethically not possible. Furthermore, ongoing registry-based passive follow-up studies with invasive cervical cancer as the end point will take time.

MATERIALS & METHODS

To evaluate the feasibility of CIN3 as a surrogate end point, we compared high-risk (hr) HPV-associated relative risk and population attributable fraction (PAF) of CIN3 and/or squamous cell carcinoma (SCC) estimated in a large serological case-cohort HPV study. Our case-cohort comprised 83 SCC and 389 CIN3 cases and a subcohort of 7862 out of 230,998 Finnish women, who at baseline were under 32 years of age and had undergone a minimum of two pregnancies within 5 years during 1983-1997.

RESULTS

PAFs of the case-cohort, approach-based, serologically defined and misclassification-corrected HPV16 and hrHPV (HPV types 16, 18, 31 and 33) exposures in the SCC samples were 61% (95% CI: 18-85) and 73% (95% CI: 13-93), respectively. Considerably lower HPV16 and hrHPV PAF estimates in CIN3 of 6% (95% CI: -19-35) and 36% (95% CI: -5-65), respectively, were obtained. A meta-analysis-derived, PCR-based, hrHPV-associated relative risk estimate of 20.3 in CIN2/3+ yielded a PAF estimate for hrHPV in CIN2/3+ of 86% (90% CI: 63-95) in our study population. The former, hrHPV serology-based CIN3 PAF estimates were biased owing to low sensitivity of HPV16 and/or HPV16/18/31/33 serology, most notably in cervical cancer precursor lesions, but the latter estimate overlapped with our hrHPV serology-based cervical cancer PAF estimate.

CONCLUSION

CIN3 may be a valid surrogate efficacy end point for HPV vaccination studies, but the associated causality of multiple hrHPV exposures needs to be unambigously defined.

Efficacy of human papillomavirus vaccines: a systematic quantitative review

Human papillomavirus (HPV) types cause approximately 70% of cervical cancer worldwide. Two vaccines have been recently evaluated in randomized controlled trials: the bivalent vaccine for HPV 16 and 18 (Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and the quadrivalent vaccine for HPV 6, 11, 16, and 18 (Gardasil, Merck and Co, Inc, Whitehouse Station, NJ). We have performed a systematic review of all randomized controlled trials in which vaccines against HPV were compared with placebo regarding efficacy, safety, and immunogenicity. Six studies met the inclusion criteria, which included 47,236 women. The first objective in this systematic review was to assess vaccine efficacy in the prevention of cytologically and/or histologically proven lesions. And the secondary objective was the evaluation of safety and vaccine immunogenicity. Bivalent and quadrivalent HPV vaccines significantly reduced the rate of lesions in the cervix, vulva, vagina, and anogenital region, with efficacy of 93% (95% confidence interval [CI], 87-96) and 62% (95% CI, 27-70), respectively, when compared with the control groups according to intention to treat. Regarding safety, we found more symptoms in the bivalent vaccine group (35%; 95% CI, 5-73) when compared with the control groups. In regard to vaccine immunogenicity, there was seroconversion in the group that received the vaccine when compared with the placebo group in the bivalent and quadrivalent vaccines. Prophylactic vaccination can prevent HPV infection in women aged 9 to 26 years not previously infected with the HPV subtypes covered by the vaccines. To evaluate cervical cancer incidence and mortality, a longer follow-up is necessary.

Detection and quantitative analysis of human herpesvirus in pilocytic astrocytoma

We investigated the hypothetical role of human herpesviruses (HHVs) in tumour formation of the cerebellum. Thirty-five samples of pilocytic astrocytoma and 10 control samples of cerebellum from patients who died of unrelated diseases were examined. Presence of the 8 known HHVs was first studied using specific real-time quantitative Polymerase Chain Reaction (qPCR) targeting viral DNA polymerase. HHV's DNA polymerase was found present in 20 samples (7 controls, 13 astrocytomas) and was absent in 25 samples (3 controls, 22 astrocytomas). DNA polymerase of Epstein-Barr Virus (EBV) was present in 16 samples, 7/10 controls (70%) and 9/35 astrocytomas (26%). HHV-1 and Varicella-Zoster virus were detected only twice and HHV-2, Cytomegalovirus, HHV-7 and HHV-8, only once. HHV-6 was not detected. In all cases, the gene copy numbers of DNA polymerase were low (<100/100 ng DNA). A second approach was to search for novel HHVs, using consensus-degenerated hybrid oligonucleotide primers (CODEHOP) PCR: no sequence indicative of a new HHV was detected. In summary, EBV was the most frequent HHV detected in pilocytic astrocytoma, but at very low levels. According to the actually accepted threshold the results suggest that EBV cannot be considered responsible for tumorigenesis of pilocytic astrocytoma.

"I have never heard that one": young girls' knowledge and perception of cervical cancer

With the advent of a vaccine for the human papillomavirus (HPV), many are claiming that cervical cancer may become a health worry of the past. While the vaccine certainly represents an important step forward in the fight against HPV and cervical cancer, it does not diminish the importance of health education or screening interventions particularly amongst adolescents. This study explores the existing state of cancer and cervical cancer knowledge of Latina and African American adolescent girls from low-income, urban neighborhoods. We found that the study participants expressed a range of attitudes toward cancer. Knowledge of cancer also was varied and somewhat anecdotal, showing no unified body of knowledge, but instead representing an assemblage of information culled from formal and informal sources. Participants were most familiar with breast and lung cancer and mentioned these types of cancer most frequently in the focus groups. Most participants had never heard of cervical cancer, while a few were familiar with several aspects of the disease. Cancer knowledge seemed to be gleaned mostly from personal stories, perhaps suggesting the pervasiveness of cancer incidence in their community. The predominant attitudes expressed toward cancer included fear, uncertainty, and anxiety. Our findings suggest that considerable continued health promotion efforts are needed to improve knowledge about cancer in general, and particularly about cervical cancer, to reduce fear and to highlight the effectiveness of prevention and screening.

Malignancies following in situ cervical cancer in Hispanic Americans and non-Hispanic Whites

OBJECTIVES

Some risk factors for cervical cancer in situ convey risk for malignancies of the cervix and other sites. We estimate risk of several malignancies following in situ cancer of the cervix for Hispanic Americans and non-Hispanic Whites.

METHODS

Using California Cancer Registry data (1988-1999) we identify 56,020 women with cervical cancer in situ and observe subsequent malignancies in that cohort, with over three million woman-months of follow-up. We focus on cancers of the reproductive system and cancers related to smoking. Risk estimates are standardized incidence ratios, accounting for age, time at risk, cancer type, and race/ethnicity.

RESULTS

There is elevated risk for invasive cervical cancer (SIR=4.1, 95% CI: 3.5-4.7), which is significantly higher for Hispanics than for non-Hispanic Whites (SIRs=5.2 and 3.2, respectively, chi2(1)=7.66, P=0.006). Excluding cervix, non-Hispanic Whites show elevated risk for a pool of reproductive cancers (SIR=1.8, 95% CI: 1.4-2.4). While both groups show elevated risk for a pool of smoking-related cancers, only non-Hispanic Whites show significant risk specifically for lung cancer (SIR=1.7, 95% CI: 1.4-2.1). Non-Hispanic Whites show elevated risk for ovarian cancer (SIR=1.8, 95% CI: 1.3-2.4). Ovarian cancer following in situ cervical cancer is disproportionately of borderline histology (G2(1)=7.43, P=0.006).

CONCLUSIONS

These results have implications for public health planning for women, as well as better understanding of disparities in care or biologic paths to malignancies in women with in situ cancer of the cervix.

Vaccines for cervical cancer

The review focuses on current and future prevention of invasive cervical cancer (ICC), the second most common cancer among women worldwide. Implementation of population-based cytological screening programmes, using the 'Pap' smear to detect pre-cancerous lesions in the cervix, has resulted in substantial declines in mortality and morbidity from ICC in North America and some European countries. However, cases of, and deaths from, ICC continue to occur. Primary prevention of infection with high-risk human papillomavirus (HPV) types, the central causal factor of ICC, could further reduce incidence of and mortality from ICC. This is particularly the case in developing countries, which bear 80% of the burden of ICC, and where effective Pap screening programmes are extremely difficult to implement. Very promising results from several trials of synthetic HPV type-specific monovalent (HPV 16) and bivalent (HPV 16 and 18) vaccines have recently been published, showing high efficacy against type-specific persistent HPV infection and development of type-specific pre-cancerous lesions. Large-scale phase III trials of a number of such vaccine candidates are currently underway, and there is real hope that an effective vaccine capable of protecting against infection with HPV types 16 and 18 (which together account for approximately 70% of cervical cancer cases worldwide), and thereby of preventing development of a very significant proportion of cases of ICC, could be available within the next 2 years.

Patent buy-outs for global disease innovations for low- and middle-income countries

The World Health Organization’s CHOICE program analyzes the cost effectiveness of various health interventions related to the Millennium Development Goals. The program identifies the best strategies for improving health in low-income countries, using a standard set of methodological assumptions. These studies evaluate interventions in many areas, including child health and HIV/AIDS.

For some of these treatments, drug costs are a significant variable: if the drug price doubles, the intervention becomes less cost effective. But if the drug price is reduced by 90%, then more therapies become affordable.

Drug prices are uniquely susceptible to radical price reductions through generic competition. Patented pharmaceuticals may be priced at more than 30 times the marginal cost of production; the excess is thepatent rentcollected by the drug company while the patent and exclusive marketing periods remain. Patent rents are significant. AIDS drugs which sell for US$10,000 per person per year in the US are sold generically for less than US$200. If patented drugs could be sold at the marginal cost of production, cost effective treatments would become even more attractive, and other interventions would become affordable.

Liposome-polycation-DNA (LPD) particle as a carrier and adjuvant for protein-based vaccines: therapeutic effect against cervical cancer

With the successful identification of many tumor-specific antigens, tumor-associated antigens, and the potential of using unfractioned tumor cell derivatives as tumor antigens, a system and/or adjuvant that can deliver these antigens and help them to induce strong and effective anti-tumor immune responses is greatly needed. Previously, we reported that a MHC class I-restricted peptide epitope derived from human papillomavirus (HPV) 16 E7 protein, when incorporated into a clinically proven safe LPD (liposome-polycation-DNA) particle, was able to effectively eradicate tumors established in mice. Cervical cancer is the second most common cancer among women worldwide. HPV infection is clearly linked to this cancer. Vaccines based on the early (E) gene products of HPV could be effective in controlling it. However, besides the fact that epitope vaccines have many limitations particularly, concerning the diverse HLAs in humans, the use of the epitope as an antigen prevented us from fully characterizing the immune responses induced by the LPD as a vaccine carrier and/or adjuvant in previous studies. In the present study, by using the HPV 16 E7 protein as an antigen, we first showed that LPD, as a vaccine carrier and adjuvant induced strong and robust immune responses, both cellular and antibody. We then showed that immunization with LPD particles incorporated with either the wild type HPV 16 E7 protein or a potentially safer mutant induced strong immune responses that caused complete regressions of a model cervical cancer tumor established in murines. LPD could be a potent vaccine carrier and/or adjuvant for many antigens.

Prophylactic human papillomavirus vaccines: the beginning of the end of cervical cancer

Persistent infection with one of the oncogenic human papillomavirus (HPV) types is a necessity for the development of cervical cancer. By HPV vaccination, cervical cancer could become a very rare disease. Two types of HPV vaccines can be distinguished: (i) therapeutic vaccines which induce cellular immunity targeted against epithelial cells infected with HPV and (ii) prophylactic vaccines inducing virus-neutralizing antibodies protecting against new but not against established infections. At present, several vaccines have been developed and tested in clinical trials. The vaccines are generally well tolerated and highly immunogenic. The current clinical data indicate that prophylactic vaccines are very effective against new persistent infections and the development of cervical intraepithelial lesions. The protection is type specific. However, the follow-up of the vaccination trials is still short. The effect of HPV vaccines on future cancer incidence will only be known after decades of follow-up. This article will address the status of recently terminated phase II and currently running phase III trials with prophylactic HPV vaccines.

Managing the sexually transmitted disease pandemic: a time for reevaluation

The serious implications of the sexually transmitted disease (STD) pandemic that currently challenges educators, medical practitioners and governments suggest that prevention strategies, which primarily focus on barrier protection and the management of infection, must be reevaluated and that initiatives focusing on primary prevention of behaviors predisposing individuals to STD risk must be adopted. Human immunodeficiency virus/acquired immunodeficiency syndrome, human papillomavirus, genital herpes, and Chlamydia are used to illustrate the pervasive presence of STDs and their serious consequences for individuals and national infrastructures. Long-term sequelae are discussed, including the emerging link between various sexually transmitted infections and cancer, and the psychosexual and psychosocial factors which impact infected individuals. Although risk reduction and treatment of existing infection is critical, the promotion of optimal life-long health can be achieved most effectively through delayed sexual debut, partner reduction, and the avoidance of risky sexual behaviors.

Cervical cancer mortality by neighbourhood income in urban Canada from 1971 to 1996

BACKGROUND

The reduction of socioeconomic inequalities in health is an explicit objective of health policy in Canada, yet rates of death from cervical cancer are known to be higher among women of low socioeconomic status than among those of higher socioeconomic status. To evaluate progress toward the World Health Organization's goal of "Health for All," we examined whether income-related differentials in cervical cancer mortality diminished from 1971 to 1996.

METHODS

Death registration data for Canada's census metropolitan areas in 1971, 1986, 1991 and 1996 were assigned to census tracts through postal code, and the tracts were in turn assigned to income quintiles based on their proportion of the population below the Statistics Canada low-income cutoff values. We compared age-standardized death rates (using the 1966 world population standard) in the female population (excluding those in institutions) across the 5 income quintiles and calculated interquintile rate ratios (poorest over richest) and interquintile rate differences (poorest minus richest).

RESULTS

From 1971 to 1996, the overall age-standardized cervical cancer death rate per 100 000 women (and 95% confidence interval) declined from 5.0 (4.5-5.6) to 1.9 (1.7-2.1), the interquintile rate ratio diminished from 2.7 (1.8-4.2) to 1.7 (1.1- 2.6), and the interquintile rate difference decreased from 4.6 (2.8- 6.4) to 1.1 (0.2-1.9).

INTERPRETATION

The income-related disparity in rates of death from cervical cancer as measured by rate ratios and rate differences diminished markedly in urban Canada from 1971 to 1996. Among the numerous factors that may have contributed to the decline (including decline in fertility and improvement in diet), one important factor was probably the implementation of effective screening programs.

Projected Clinical Benefits and Cost-effectiveness of a Human Papillomavirus 16/18 Vaccine

BACKGROUND

Human papillomavirus (HPV) vaccine may be commercially available in a few years. We explored the clinical benefits and cost-effectiveness of introducing an HPV16/18 vaccine in a population with an organized cervical cancer screening program.

METHODS

A computer-based model of the natural history of HPV and cervical cancer was used to project cancer incidence and mortality, life expectancy (adjusted and unadjusted for quality of life), lifetime costs, and incremental cost-effectiveness ratios (i.e., the additional cost of a strategy divided by its additional clinical benefit compared with the next most expensive strategy) associated with different cancer prevention policies, including vaccination (initiated at age 12 years), cytologic screening (initiated at 18, 21, 25, 30, or 35 years), and combined vaccination and screening strategies. We assumed that vaccination was 90% effective in reducing the risk of persistent HPV16/18 infections and evaluated alternative assumptions about vaccine efficacy, waning immunity, and risk of replacement with non-16/18 HPV types.

RESULTS

Our model showed that the most effective strategy with an incremental cost-effectiveness ratio of less than 60 dollars-000 per quality-adjusted life year is one combining vaccination at age 12 years with triennial conventional cytologic screening beginning at age 25 years, compared with the next best strategy of vaccination and cytologic screening every 5 years beginning at age 21 years. This triennial strategy would reduce the absolute lifetime risk of cervical cancer by 94% compared with no intervention. These results were sensitive to alternative assumptions about the underlying patterns of cervical cancer screening, duration of vaccine efficacy, and natural history of HPV infection in older women.

CONCLUSIONS

Our model predicts that a vaccine that prevents persistent HPV16/18 infection will reduce the incidence of HPV16/18-associated cervical cancer, even in a setting of cytologic screening. A program of vaccination that permits a later age of screening initiation and a less frequent screening interval is likely to be a cost-effective use of health care resources.

Chapter 22. Non-HIV antiviral agents

This chapter focuses on non-HIV antiviral agents. The development of antiviral agents to treat non-HIV infections is largely focused on therapies for the treatment of chronic hepatitis infections B and C. Nucleoside analog continue to be the mainstay of Hepatitis B Virus (HBV) therapeutics. The first small molecule inhibitor of Hepatitis C Virus (HCV), the NS3 protease inhibitor BILN-2061, entered phase 2 clinical trials, producing a striking reduction in viral load in treated individuals. The development of the HCV replicon system and its application to screening for antiviral agents provided tangible benefit with the disclosure of mechanistically and structurally diverse HCV inhibitors. Adefovir dipivoxil has been approved in the United States and the European Union for the treatment of HBV, providing a second small molecule antiviral to add to lamivudine (3TC) and the injectable protein IFNα as the only approved agents for treating HBV infection. The chapter also provides details of the inhibitors of hepatitis B and C virus, the inhibitors of simplex virus and human cytomegalovirus, the inhibitors of respiratory viruses and the inhibitors of West Nile virus and Papilloma virus.

Innovations in understanding the biology of cervical cancer

Revelation of the connection between the human papillomavirus (HPV) and cervical neoplasia and invasive cervical cancer is prompting new investigations to expand that understanding and promote vaccines, gene therapy, and other interventions. At the Second International Conference on Cervical Cancer (Houston, TX, April 11-14, 2002), laboratory and clinical researchers reported advances in new studies meant to increase understanding of the natural history of HPV and cervical intraepithelial neoplasia, to evaluate new cervical cancer screening techniques, and to promote new therapies. Using K14-HPV type 16 transgenic mice, researchers are investigating the effects of estrogen on cervical cancer carcinogenesis, and results are lending support to epidemiological theories showing a difference in HPV infection rates and the development of cervical lesions in women using oral contraceptives. Other work involves investigating genes that are up-regulated by HPV infection and the role of the p53 homologue, p63, in cervical neoplasia evolution. Telomerase also is under investigation as a biomarker in high-risk populations. Gene therapy that replaced p53 in cervical cancer cell lines in vitro and a nude mouse model inhibited cell and tumor growth, confirming previous findings in squamous epithelial carcinomas of the head and neck. Furthermore, research in intracellular targeting of antigens to subcellular locations shows promise for treating cervical cancer preclinically. Identification of molecular changes in cervical cancer and knowledge about the importance of HPV infection in cervical cancer can lead to new therapies to treat existing cervical cancer and, in the long term, prevent the disease.

Cervical cancer vaccines: recent advances in HPV research

Carcinomas of the anogenital tract, particularly cancer of the cervix, account for almost 12% of all cancers in women, and so represent the second most frequent gynecological malignancy in the world (48). It is well established that chronic infection of cervical epithelium by human papillomaviruses (HPV) is necessary for the development of cervical cancer. In fact, HPV DNA has been demonstrated in more than 99.7% of cervical cancer biopsy specimens, with high-risk HPV16 and HPV18 sequences being most prevalent (45,73). Therefore, an effective vaccine that would mount an immune response against HPV-related proteins might contribute to the prevention or elimination of HPV expressing lesions. This review will concentrate on the most recent advances in vaccine-mediated prevention and immunotherapy of HPV-induced cervical cancer, including presentations from the 20(th) International HPV Conference held in October 2002 in Paris.