Interventions for encouraging sexual behaviours intended to prevent cervical cancer
Behaviour change interventions such as condom use and improved sexual health knowledge are likely to be effective in protecting women against STI transmission. However, the effectiveness of these interventions specifically for reducing cervical cancer incidence remains uncertain.
RHL Commentary by Broutet N
In 2008, cervical cancer was associated with some 275 000 deaths, of which about 88% occurred in low- and middle-income countries. Cervical cancer is the third most common cancer in women and the most common cancer in many low- and middle-income countries (1). With population growth and aging, the number of cervical cancer cases is expected to increase another 1.5-fold by 2030. Virtually all squamous-cell cervical cancer cases (99%) are linked to genital infection with the human papillomavirus (HPV), which is the most common viral infection of the reproductive tract and one of the most common sexually transmitted infections (STI). The peak incidence of HPV infection occurs between the ages of 16 and 20 years, after the first sexual intercourse. The natural history of HPV infection coupled with the ability to clinically access the cervix makes cervical cancer the most preventable and treatable of all types of cancer. The dual application of primary (vaccination and sexual health information) and secondary (screening and treatment for cervical pre-cancer) prevention strategies offers an opportunity for comprehensive control of this cancer.
In terms of non-vaccine-related primary prevention, sexual and reproductive health services can play a key role in promoting condom use as part of a sexual health-care package that includes dual protection counselling to prevent not only unplanned pregnancy but also the transmission of STIs, including HIV. The package could also include education on sexual behaviours to prevent cervical cancer. A meta-analysis of studies looking at outcomes following self-reported condom use (2) showed that although infection with HPV was not prevented, condom use may have had a protective effect against genital warts, dysplasia and invasive cervical cancer. The Cochrane review which is the subject of this commentary (3) is important because it assesses the effectiveness of “behavioural” interventions for young women to encourage safer sexual behaviours aimed at preventing the transmission of STIs (including HPV) and cervical cancer.
2. METHODS OF THE REVIEW
Systematic literature searches were derived from two main sources: electronic database and hand-searching. All references were screened for inclusion against selection criteria: randomized controlled trials of behavioural interventions for young women up to the age of 25 years that all included behaviour changes designed to promote condom use and also, among other things, information provision about the transmission and prevention of STIs. The trials had to have measured behavioural outcomes (e.g. condom use, sexual partner reduction, and reduction in sexual intercourse) and/or biological outcomes (e.g. incidence of STIs and cervical cancer). For the analysis, a narrative synthesis was conducted. A meta-analysis was not considered appropriate owing to heterogeneity between the interventions and trial populations. The methods are very clearly explained and are easy to follow in the review. However, there is insufficient detail about who or how many reviewers selected the studies. Assessment of the risk of bias for each of included study is clearly stated. Data are very well reported in the tables and in the text. However, a summary table of all outcomes would have been helpful, in addition to individual, very detailed tables for each outcome. The text is very helpful for the synthesis of the findings.
3. RESULTS OF THE REVIEW
A total of 5271 studies were screened, and out of these 23 randomized controlled trials met the inclusion criteria. Most of the trials had been conducted in the USA in health-care clinics (e.g. family planning). The majority of interventions involved providing information about STIs and teaching safer sex skills (e.g. communication), occasionally supplemented with provision of resources (e.g. free sexual health-care services). The trials were heterogeneous in terms of duration, contact time, type of providers, behaviour change objectives and outcomes. The effectiveness of behavioural interventions was mixed: statistically significant effects for behavioural outcomes (such as condom use, or improved knowledge) were frequently reported in the trials, while there were very few significant effects for biological outcomes (such as STI incidence). The review authors did not find any studies that had specifically evaluated impact of interventions on cervical cancer or even HPV infection. STIs and HIV incidence were used as a proxy for biological markers, supposing that decrease in STI will relate to the decrease on HPV and therefore impact on cervical cancer.
The review concludes that behaviour change interventions (such as condom use and improved sexual health knowledge) are likely to be effective in protecting women against STI transmission. This finding is corroborated by another systematic review of 42 studies published in December 2011 (4) on the efficacy of behavioural interventions to increase condom use and reduce STIs. However, the effectiveness of these interventions specifically for reducing cervical cancer incidence remains uncertain.
4.1 Applicability of the results
The evidence presented in this review was obtained mainly from studies conducted in the USA. The focus of the included studies was young women up to 25 years of age and the interventions were designed to be culturally relevant to African-American women. Hence, the results may not be applicable to other settings, especially since sexual behaviour interventions are highly dependent not only on sociocultural context, but can also be affected by the behaviour of sexual partners. Interventions designed to increase condom use, delay age at first intercourse, and reduce the number of partners, are broadly effective in reducing STI and HIV transmission, although their specific efficacy in terms of reducing cervical cancer incidence remains unknown.
4.2 Implementation of the intervention
Implementation of interventions to change sexual behaviours requires a system to be in place to define the interventions, train professionals (health-care providers, school teachers, social workers, etc.) who will deliver them, schedule the time for delivery of interventions, develop appropriate supporting instruments (media strategy, information products, etc.), ensure repetition of the interventions, and implement a monitoring and evaluation system. It is also crucial to constitute a multicultural and multidisciplinary group of stakeholders to ensure that the proposed interventions are socioculturally acceptable to the community in which they are to be implemented and to manage potential controversies. There is considerable literature available on implementation of behavioural change strategies for STIs, including HIV (see for example reference 5).
The majority of the trials included in this review involved interventions that were delivered in health-care settings. The studies did not consider the possibility of involving schools. Recent work in this area points to the importance of targeting sexual health interventions at schoolchildren and designing interventions for specific age groups and sociocultural contexts. Hence, behavioural interventions aiming to increase condom use, delaying the age of first sexual intercourse, or decreasing the numbers of sexual partners may benefit from being provided in settings where there is time for discussion and information (such as schools, colleges, etc.). School enrolment rates are increasing in low- and middle-income countries, even for girls, and this is certainly a setting which deserves further considerations.
4.3 Implications for research
Very little is known about the information needs of specific population groups. More formative research should be conducted to understand those needs in specific settings in different populations, in particular in young people, high-risk populations for STI and HIV or different immigrant populations. It is also important to understand better the association between behavioural and biological outcomes. For example, interventions that reduces STI incidence may not reduce HIV incidence, since the efficacy of behavioural interventions also depends on factors associated with sexual risk behaviours. The delivery of HPV vaccines in countries to young adolescents may be also an opportunity to measure the impact of sexual behaviour interventions on STIs incidence.
- Ferlay J et al. GLOBOCAN 2008; cancer fact sheet. All cancers (excluding non-melanoma skin cancer) incidence and mortality worldwide in 2008. IARC CancerBase. Lyon, International Agency for Research on Cancer, 2010; http://globocan.iarc.fr/factsheets/cancers/all.asp; accessed 6 March 2012.
- Manhart LE, Koutsky LA. Do condoms prevent genital HPV infection, external genital warts, or cervical neoplasia? A meta-analysis. Sexually Transmitted Diseases 2002;29:725-735.
- Shepherd JP, Frampton GK, Harris P. Interventions for encouraging sexual behaviours intended to prevent cervical cancer. Cochrane Database of Systematic Reviews 2011;Issue 4. Art. No.: CD001035; DOI: 10.1002/14651858.CD001035.pub2.
- Scott-Sheldon L, Huedo-Medina TB, Warren MR, Johnson BT, Carey MP. Efficacy of behavioural interventions to increase condom use and reduce sexually transmitted infections: a meta-analysis, 1991 to 2010. Journal of Acquired Immune Deficiency Syndrome 2011;58:489-498.
- Coates TJ, Richter L, Cacere C. Behavioural strategies to reduce HIV transmission: how to make them work better. The Lancet;372:669-684; DOI: 10.1016/S0140-6736(08)60886-7.
This document should be cited as: Broutet N. Interventions for encouraging sexual behaviours intended to prevent cervical cancer (last revised: 1 April 2012). The WHO Reproductive Health Library; Geneva: World Health Organization.