The World Health Organization (WHO) has updated its fact sheet on Human Papillomavirus (HPV) and cervical cancer.
Human papillomavirus (HPV) is the most common viral infection of the reproductive tract.
Most sexually active women and men will be infected at some point in their lives and some may be repeatedly infected.
The peak time for acquiring infection for both women and men is shortly after becoming sexually active.
HPV is sexually transmitted, but penetrative sex is not required for transmission. Skin-to-skin genital contact is a well-recognized mode of transmission.
There are many types of HPV, and many do not cause any problems. 90% of HPV infections resolve spontaneously within 2 years.
A small proportion of infections with certain types of HPV can persist and progress to cancer.
Cervical cancer is by far the most common HPV-related disease. Nearly all cases of cervical cancer can be attributable to HPV infection.
Non-cancer causing types of HPV (especially types 6 and 11) can cause genital warts and respiratory papillomatosis (a disease in which tumours grow in the air passages leading from the nose and mouth into the lungs).
Genital warts are very common and highly infectious.
Worldwide, cervical cancer is the fourth most frequent cancer in women with an estimated 530 000 new cases in 2012 representing 7.5% of all female cancer deaths. Of the estimated more than 270 000 deaths from cervical cancer every year, more than 85% of these occur in less developed regions.
The high mortality rate from cervical cancer globally (52%) could be reduced by effective screening and treatment programmes.
HPV infection and development of cervical cancer
There is a risk for all women that HPV infection may become chronic and pre-cancerous lesions progress to invasive cervical cancer.
It takes 15 to 20 years for cervical cancer to develop in women with normal immune systems. It can take only 5 to 10 years in women with weakened immune systems, such as those with untreated HIV infection.
Risk factors for HPV persistence and development of cervical cancer
- Early first sexual intercourse
- Multiple sexual partners
- Tobacco use
- Immune suppression (for example, HIV-infected individuals are at higher risk of HPV infection and are infected by a broader range of HPV types)
Signs and symptoms
Persistent infection with specific types of HPV (most frequently types 16 and 18) may lead to precancerous lesions.
If untreated, these lesions may progress to cervical cancer, but this progression usually takes many years.
Symptoms of cervical cancer tend to appear only after the cancer has reached an advanced stage and may include:
- irregular, intermenstrual (between periods) or abnormal vaginal bleeding after sexual intercourse;
- back, leg or pelvic pain;
- fatigue, weight loss, loss of appetite;
- vaginal discomfort or odourous discharge; and
- a single swollen leg.
Screening for cervical cancer
Cervical cancer screening is testing for pre-cancer and cancer among women who have no symptoms and may feel perfectly healthy. When screening detects pre-cancerous lesions, these can easily be treated and cancer avoided. Screening can also detect cancer at an early stage and treatment has a high potential for cure.
Because pre-cancerous lesions take many years to develop, screening is recommended for every woman from aged 30 to 49 at least once in a lifetime and ideally more frequently. Screening is only effective on cervical cancer mortality, if a high proportion of women participate.
There are 3 different types of screening tests are currently available:
- conventional (Pap) test and liquid-based cytology (LBC)
- visual inspection with Acetic Acid (VIA)
- HPV testing for high-risk HPV types.
There are currently 2 vaccines which protect against both HPV 16 and 18, which are known to cause at least 70% of cervical cancers. The vaccines may also have some cross-protection against other less common HPV types which cause cervical cancer. One of the vaccines also protects against HPV types 6 and 11 which cause anogenital warts.
Clinical trial results show that both vaccines are safe and very effective in preventing infection with HPV 16 and 18.
Both vaccines work best if administered prior to exposure to HPV. Therefore, it is preferable to administer them before first sexual activity.
The vaccines cannot treat HPV infection or HPV-associated disease such as cancer.
Some countries have started to vaccinate boys as the vaccination prevents genital cancers in males as well as females, and one of the two available vaccines also prevents genital warts in males and females.
WHO recommends vaccination for girls aged 9-13 years as this is the most cost-effective public health measure against cervical cancer.
HPV vaccination does not replace cervical cancer screening. In countries where HPV vaccine is introduced, screening programmes may still need to be developed or strengthened.
WHO recommendations for cervical cancer prevention and control
Primary prevention begins with HPV vaccination of girls aged 9-13 years, before they become sexually active.
Other recommended preventive interventions for boys and girls as appropriate are:
- education about safe sexual practices, including delayed start of sexual activity;
- promotion and provision of condoms for those already engaged in sexual activity;
- warnings about tobacco use, which often starts during adolescence, and which is an important risk factor for cervical and other cancers; and
- male circumcision.
Women who are sexually active should be screened for abnormal cervical cells and pre-cancerous lesions, starting from 30 years of age.
If treatment is needed to excise abnormal cells or lesions, cryotherapy (destroying abnormal tissue on the cervix by freezing it) is recommended.
If signs of cervical cancer are present, treatment options for invasive cancer include surgery, radiotherapy and chemotherapy.
Link to the updated fact sheet:
Link to WHO review of HPV and HPV vaccines:
Link to WHO’s ‘Facts about HPV’ page: