Aspects of prophylactic vaccination against cervical cancer and other human papillomavirus-related cancers in developing countries

The interplay of HIV and human papillomavirus-related cancers in sub-Saharan Africa: scoping review

BACKGROUND

People living with HIV (PLHIV) are at a high risk of developing HPV-related cancers. HPV-related malignancies occur frequently and/or are high among PLHIV, with cervical cancer as a designated AIDS-defining condition. We aimed to explore the evidence on the interplay of HIV and HPV-related cancers in sub-Saharan Africa (SSA).

METHODS

The scoping review was guided by Arksey and O'Malley's framework. We searched for literature from the following databases: PubMed; World Health Organization (WHO) Library; Science Direct; Google Scholar and EBSCOhost (Academic search complete, Health Source: Nursing/Academic Edition, CINAHL). Studies reporting on evidence HIV and HPV-related cancers interplay in SSA were eligible for inclusion in this review. The Mixed Methods Appraisal Tool (MMAT) tool was used to assess the risk of bias of the included studies. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was used for reporting the search results. Thematic analysis used to reveal the emerging themes from the included studies.

RESULTS

A total of 74 potentially eligible articles were screened. Of these, nine (7 reviews, 1 transversal case controls, and 1 quantitative study) were eligible for data extraction. The studies reported about a total of 16,351 participants in different settings. The nine included studies showed evidence of cervical cancer among HIV-infected women and distribution of HPV infection and cervical abnormalities among HIV-positive individuals. In the four studies generalizing about HIV and anal cancer, only one reported about HPV. Two studies generally reported about HIV and head and neck cancers and one reported about interaction of HIV with vaginal cancer, vulvar cancer, and penile cancer, respectively.

CONCLUSION

HIV positivity is associated with increased prevalence of HPV infection on different anatomic sites, which will result in increased burden of HPV-related cancers among PLHIV. Furthermore, primary studies with robust study designs aimed at investigating the risk developing HPV-related cancers among PLHIV are recommended. Systematic review registration: PROSPERO CRD42017062403.

Evidence on the prevalence, incidence, mortality and trends of human papilloma virus-associated cancers in sub-Saharan Africa: systematic scoping review

BACKGROUND

Human papilloma virus (HPV) associated cervical cancer remains a global concern particular, in Sub-Saharan Africa (SSA) where the impact is felt most. Evidence show that many other cancers such as vaginal, anal, oropharyngeal, penile are because of persistent infection with HPV especially, high-risk types.

AIM

We mapped evidence on the incidence, prevalence, mortality, and the trends of human papillomavirus-related cancers in SSA.

METHODS

A comprehensive literature search was conducted from several databases including PubMed, Google scholar, Science Direct, and CINAHL and MEDLINE via EBSCOhost as well as World Health Organization website for grey literature. Studies reporting HPV-related cancers in SSA outcomes including prevalence, incidence, mortality, and trends were included in this study. The risk of bias of the included studies were assessed using the mixed methods appraisal tool version 2011. We employed PRISMA (preferred reporting items for systematic reviews and meta-analyses) to report the search results. Thematic analysis used to reveal the emerging themes from the included studies.

RESULTS

Seventy-four (74) studies were retrieved at full article screening, eight of them (six reviews, and two quantitative study) were eligible for data extraction. The degree of agreement between the two independent reviewers following full article screening, was 86.49% agreement versus 64.57% likely by chance which constituted moderate to significant agreement (Kappa statistic = 0.62, p-value< 0.05). Of the eight included studies, four (50%) studies generalized about SSA with no country of interest; two (25%) studies were conducted in Nigeria; one (12.5%) reported about Uganda, Zambia, Guinea, Malawi Tanzania, Mali, Mozambique, Zimbabwe; and one (12.5%) reported about Ethiopia, Senegal, Zimbabwe and Uganda. These eight included studies reported evidence on more than one outcome of interest. Four studies reported about the prevalence of HPV-related cancers, seven studies reported about the incidence, four studies reported about mortality, and four studies reported about the trends of HPV-related cancers.

CONCLUSION

This study observation highlighted a gap of knowledge regarding the epidemiological data on the recent HPV prevalence in SSA, which will have a potential impact in determining the distribution of HPV on different body sites (cervix, penis, vagina, vulva, anus and oropharynx). Ongoing research projects are recommended in SSA to enhance the value of HPV, and HPV-associated cancers epidemiological data to inform strategies or/and policies on prevention, diagnosis, and treatment of HPV-related conditions.

[Vaccines as an agent for immunization against HPV]

Considered a highly prevalent infection throughout the world, the human papillomavirus (HPV) is a DNA virus that infects the genital mucosa and has high carcinogenic potential, being related to an increased risk of lower genital tract lesions, such as cervical cancer. This cancer is responsible for the deaths of about 231,000 women per year worldwide, which means that HPV is a major problem for public health. Knowing that the most effective and cost-effective way to control an infectious disease is the development of vaccines, two prophylactic vaccines have been developed and approved in Brazil, one of which is bivalent and the other is tetravalent. This review of the literature seeks to present the characteristics of the HPV virus, types of vaccines available on the market, their indications and contraindications, their adverse effects, their effectiveness, their geometric mean titer (GMT) and their cost-effectiveness.

CDKN3 mRNA as a Biomarker for Survival and Therapeutic Target in Cervical Cancer

The cyclin-dependent kinase inhibitor 3 (CDKN3) gene, involved in mitosis, is upregulated in cervical cancer (CC). We investigated CDKN3 mRNA as a survival biomarker and potential therapeutic target for CC. CDKN3 mRNA was measured in 134 CC and 25 controls by quantitative PCR. A 5-year survival study was conducted in 121 of these CC patients. Furthermore, CDKN3-specific siRNAs were used to investigate whether CDKN3 is involved in proliferation, migration, and invasion in CC-derived cell lines (SiHa, CaSki, HeLa). CDKN3 mRNA was on average 6.4-fold higher in tumors than in controls (p = 8 x 10⁻⁶, Mann-Whitney). A total of 68.2% of CC patients over expressing CDKN3 gene (fold change ≥ 17) died within two years of diagnosis, independent of the clinical stage and HPV type (Hazard Ratio = 5.0, 95% CI: 2.5–10, p = 3.3 x 10⁻⁶, Cox proportional-hazards regression). In contrast, only 19.2% of the patients with lower CDKN3 expression died in the same period. In vitro inactivation of CDKN3 decreased cell proliferation on average 67%, although it had no effect on cell migration and invasion. CDKN3 mRNA may be a good survival biomarker and potential therapeutic target in CC.

Developing the Evidence Base to Inform Best Practice: A Scoping Study of Breast and Cervical Cancer Reviews in Low- and Middle-Income Countries

BACKGROUND

Breast and cervical cancers have emerged as major global health challenges and disproportionately lead to excess morbidity and mortality in low- and middle-income countries (LMICs) when compared to high-income countries. The objective of this paper was to highlight key findings, recommendations, and gaps in research and practice identified through a scoping study of recent reviews in breast and cervical cancer in LMICs.

METHODS

We conducted a scoping study based on the six-stage framework of Arskey and O'Malley. We searched PubMed, Cochrane Reviews, and CINAHL with the following inclusion criteria: 1) published between 2005-February 2015, 2) focused on breast or cervical cancer 3) focused on LMIC, 4) review article, and 5) published in English.

RESULTS

Through our systematic search, 63 out of the 94 identified cervical cancer reviews met our selection criteria and 36 of the 54 in breast cancer. Cervical cancer reviews were more likely to focus upon prevention and screening, while breast cancer reviews were more likely to focus upon treatment and survivorship. Few of the breast cancer reviews referenced research and data from LMICs themselves; cervical cancer reviews were more likely to do so. Most reviews did not include elements of the PRISMA checklist.

CONCLUSION

Overall, a limited evidence base supports breast and cervical cancer control in LMICs. Further breast and cervical cancer prevention and control studies are necessary in LMICs.

Mitosis is a source of potential markers for screening and survival and therapeutic targets in cervical cancer

The effect of preventive human papillomavirus (HPV) vaccination on the reduction of the cervical cancer (CC) burden will not be known for 30 years. Therefore, it's still necessary to improve the procedures for CC screening and treatment. The objective of this study was to identify and characterize cellular targets that could be considered potential markers for screening or therapeutic targets. A pyramidal strategy was used. Initially the expression of 8,638 genes was compared between 43 HPV16-positive CCs and 12 healthy cervical epitheliums using microarrays. A total of 997 genes were deregulated, and 21 genes that showed the greatest deregulation were validated using qRT-PCR. The 6 most upregulated genes (CCNB2, CDC20, PRC1, SYCP2, NUSAP1, CDKN3) belong to the mitosis pathway. They were further explored in 29 low-grade cervical intraepithelial neoplasias (CIN1) and 21 high-grade CIN (CIN2/3) to investigate whether they could differentiate CC and CIN2/3 (CIN2+) from CIN1 and controls. CCNB2, PRC1, and SYCP2 were mostly associated with CC and CDC20, NUSAP1, and CDKN3 were also associated with CIN2/3. The sensitivity and specificity of CDKN3 and NUSAP1 to detect CIN2+ was approximately 90%. The proteins encoded by all 6 genes were shown upregulated in CC by immunohistochemistry. The association of these markers with survival was investigated in 42 CC patients followed up for at least 42 months. Only CDKN3 was associated with poor survival and it was independent from clinical stage (HR = 5.9, 95%CI = 1.4-23.8, p = 0.01). CDKN3 and NUSAP1 may be potential targets for the development of screening methods. Nevertheless, further studies with larger samples are needed to define the optimal sensitivity and specificity. Inhibition of mitosis is a well-known strategy to combat cancers. Therefore, CDKN3 may be not only a screening and survival marker but a potential therapeutic target in CC. However, whether it's indispensable for tumor growth remains to be demonstrated.

Assessment of eight HPV vaccination programs implemented in lowest income countries

BACKGROUND

Cervix cancer, preventable, continues to be the third most common cancer in women worldwide, especially in lowest income countries. Prophylactic HPV vaccination should help to reduce the morbidity and mortality associated with cervical cancer. The purpose of the study was to describe the results of and key concerns in eight HPV vaccination programs conducted in seven lowest income countries through the Gardasil Access Program (GAP).

METHODS

The GAP provides free HPV vaccine to organizations and institutions in lowest income countries. The HPV vaccination programs were entirely developed, implemented and managed by local institutions. Institutions submitted application forms with institution characteristics, target population, communication delivery strategies. After completion of the vaccination campaign (3 doses), institutions provided a final project report with data on doses administered and vaccination models. Two indicators were calculated, the program vaccination coverage and adherence. Qualitative data were also collected in the following areas: government and community involvement; communication, and sensitization; training and logistics resources, and challenges.

RESULTS

A total of eight programs were implemented in seven countries. The eight programs initially targeted a total of 87,580 girls, of which 76,983 received the full 3-dose vaccine course, with mean program vaccination coverage of 87.8%; the mean adherence between the first and third doses of vaccine was 90.9%. Three programs used school-based delivery models, 2 used health facility-based models, and 3 used mixed models that included schools and health facilities. Models that included school-based vaccination were most effective at reaching girls aged 9-13 years. Mixed models comprising school and health facility-based vaccination had better overall performance compared with models using just one of the methods. Increased rates of program coverage and adherence were positively correlated with the number of vaccination sites. Qualitative key insights from the school models showed a high level of coordination and logistics to facilitate vaccination administration, a lower risk of girls being lost to follow-up and vaccinations conducted within the academic year limit the number of girls lost to follow-up.

CONCLUSION

Mixed models that incorporate both schools and health facilities appear to be the most effective at delivering HPV vaccine. This study provides lessons for development of public health programs and policies as countries go forward in national decision-making for HPV vaccination.

Safety reporting in developing country vaccine clinical trials-a systematic review

With more vaccines becoming available worldwide, vaccine research is on the rise in developing countries. To gain a better understanding of safety reporting from vaccine clinical research in developing countries, we conducted a systematic review in Medline and Embase (1989-2011) of published randomized clinical trials (RCTs) reporting safety outcomes with ≥50% developing country participation (PROSPERO systematic review registration number: CRD42012002025). Developing country vaccine RCTs were analyzed with respect to the number of participants, age groups studied, inclusion of safety information, number of reported adverse events following immunization (AEFI), type and duration of safety follow-up, use of standardized AEFI case definitions, grading of AEFI severity, and the reporting of levels of diagnostic certainty for AEFI. The systematic search yielded a total number of 50 randomized vaccine clinical trials investigating 12 different vaccines, most commonly rotavirus and malaria vaccines. In these trials, 94,459 AEFI were reported from 446,908 participants receiving 735,920 vaccine doses. All 50 RCTs mentioned safety outcomes with 70% using definitions for at least one AEFI. The most commonly defined AEFI was fever (27), followed by local (16) and systemic reactions (14). Logistic regression analysis revealed a positive correlation between the implementation of a fever case definition and the reporting rate for fever as an AEFI (p=0.027). Overall, 16 different definitions for fever and 7 different definitions for erythema were applied. Predefined AEFI case definitions by the Brighton Collaboration were used in only two out of 50 RCTs. The search was limited to RCTs published in English or German and may be missing studies published locally. The reported systematic review suggests room for improvement with respect to the harmonization of safety reporting from developing country vaccine clinical trials and the implementation of standardized case definitions.