HPV vaccination and cancer prevention

Prophylactic vaccines have been found to be highly effective in preventing infection and pre-invasive and invasive cervical, vulvovaginal and anal disease caused by the vaccine types. HPV vaccines contain virus-like particles that lack the viral genome and produce high titres of neutralising antibodies. Although the vaccines are highly effective in preventing infections, they do not enhance clearance of existing infections. Vaccination programmes target prepubertal girls and boys prior to sexual debut as efficacy is highest in HPV naïve individuals. School-based programmes achieve higher coverage, although implementation is country specific. Vaccination of older women may offer some protection and acceleration of impact, although this may not be cost-effective. HPV-based screening will continue for vaccinated cohorts, although intervals may increase.     

The impact of anti HPV vaccination on cervical cancer incidence and HPV induced cervical lesions: consequences for clinical management

Cervical cancer is the second most common cause of cancer-related deaths in women worldwide. Screening for cervical cancer is accomplished utilizing a Pap smear and pelvic exam. While this technology is widely available and has reduced cervical cancer incidence in industrialized nations, it is not readily available in third world countries in which cervical cancer incidence and mortality is high. Development of cervical cancer is associated with infection with high risk types of human papillomavirus (HPV) creating a unique opportunity to prevent or treat cervical cancer through anti-viral vaccination strategies. Several strategies have been examined in clinical trials for both the prevention of HPV infection and the treatment of pre-existing HPV-related disease. Clinical trials utilizing prophylactic vaccines containing virus-like particles (VLPs) indicate good vaccine efficacy and it is predicted that a prophylactic vaccine may be available within the next five years. But, preclinical research in this area continues in order to deal with issues such as cost of vaccination in underserved third world populations. A majority of clinical trials using therapeutic agents which aim to prevent the progression of pre-existing HPV associated lesions or cancers have shown limited efficacy in eradicating established tumors in humans possibly due to examining patients with more advanced-stage cancer who tend to have decreased immune function. Future trends in clinical trials with therapeutic agents will examine patients with early stage cancers or pre-invasive lesions in order to prevent invasive cervical cancer. Meanwhile, preclinical studies in this field continue and include the further exploration of peptide or protein vaccination, and the delivery of HPV antigens in DNA-based vaccines or in viral vectors. Given that cervical cancers are caused by the human papillomavirus, the prospect of therapeutic vaccination to treat existing lesions and prophylactic vaccination to prevent persistent infection with the virus are high and may be implemented in the near future. The consequences for clinical management may include a significant reduction in the frequency of Pap smear screening in the case of prophylactic vaccines, and the availability of less invasive and disfiguring treatment options for women with pre-existing HPV associated lesions in the case of therapeutic vaccines. Implementation of both prophylactic and therapeutic vaccine regimens could result in a significant reduction of health care costs and reduction of worldwide cervical cancer incidence.     

Cervical cancer and low-risk HPV; a case report

A case of cervical cancer in a 32-year-old woman with a genotype 6 HPV genital infection that developed from a cervical low-grade SIL after a LLETZ procedure two years before is presented. This case obliges us to reconsider both the benign nature of low-grade lesions and the potentially good prognosis of low-risk HPV infection.     

Cervical response to vaccination against HPV16 E7 in case of severe dysplasia

OBJECTIVE: To evaluate the tolerance to vaccination against human papillomavirus (HPV)16 E7 (in SB adjuvant ASO2B) and its histological and immunohistological effects on HPV16 associated high-grade cervical dysplasias associated with HPV16. STUDY DESIGN: Five patients with histologically demonstrated severe cervical dysplasia (CIN3) HPV16 positive were injected three times before conization was performed 2 months after the first injection. We studied cytological, histological, proliferative pattern and immune profile before and after vaccination. The slides were compared with those obtained from non-injected patients. RESULTS: The injections were well tolerated and the specimens displayed a limited regression of the lesions. Nevertheless, massive CD4 and CD8 T cell lymphocytic infiltration was noticed after vaccination. DISCUSSION: We conclude that the vaccination we used provides an obvious immune histological reaction in the HPV infected cervix and that the 2 months delay before the final step (conization) is done is probably too short.     

Cervical cancer: Evolving prevention strategies for developing countries

Although highly preventable, cervical cancer is a leading cause ofillness and death from cancer among women in many regions, 80 per cent of deaths occur in women in developing countries. Scarce resources, limited infrastructure and competing health priorities have prevented most developing country health systems from implementing successful cervical cancer prevention and control programmes. Existing resources have typicallybeen allocated to high-cost treatment for late-stage disease, which rarely saves women's lives. Alternate approaches, including visual inspection techniques for screening and treatment on an outpatientbasis by health workers, may help to make prevention programmes more viable where resources are limited. Public health approaches for preventing cervical cancer are essential to reducing mortality.     

Cervical cancer prevention using visual screening methods

Although cervical cancer is only the fifth leading cause of cancer deaths in women globally, it remains the leading cause of cancer deaths among women in developing countries. The approach to cervical cancer prevention used in developed countries has failed in most of the world because widespread Pap smear screening and the evaluation by specialists of women who screen positive is expensive and requires an infrastructure that is not easily sustainable in most developing countries. Over the last decade, investigators have explored alternative strategies for cervical cancer prevention that may be easier to implement in developing countries. These include HPV DNA (human papillomavirus DNA) testing, cervicography, and direct visualisation techniques.¹ Of these, direct visual inspection has received the most attention because it is thought to be the least expensive and to have the greatest potential for screening and treatment in one visit. Multiple studies have now evaluated visual screening methods in developing countries. However, presumptions that parameters of effectiveness in controlled research settings can be projected to mass screening programmes may have inherent fallacies. We believe caution is needed when introducing a new approach to screening that could lead to overtreatment of large numbers of women without disease, in efforts to capture and prevent all disease. This paper examines the implications of the expanded use of direct visual inspection (DVI) for screening or diagnosis, raising the difficult question of risks and benefits when treating many to save a few.     

Young multiethnic women's attitudes toward the HPV vaccine and HPV vaccination

Objective

To investigate the acceptability of the HPV vaccine among a multiethnic sample of young women in Malaysia.

Methods

A qualitative study of 40 young women aged between 13 and 27 years recruited into 7 focus groups to discuss their knowledge of HPV infection, and their attitudes toward and acceptance of the HPV vaccine. The women were divided into Malay, Chinese, and Indian groups to allow for comparison among ethnicities.

Results

Poor knowledge about HPV did not influence the HPV vaccine's acceptability. Although participants were in favor of the vaccine, the majority preferred to delay vaccination because it is newly introduced, they did not perceive themselves to be at risk of HPV infection, or because of cost factors. Concerns were raised regarding the vaccine's safety, the potential to be perceived as promiscuous and sexually active, and whether the vaccine was halal.

Conclusion

Promotion of the HPV vaccine should take account of social and cultural acceptability. The findings will help develop strategies for effective vaccination initiatives in a multiethnic and multireligious Asian society.