WHO updates fact sheet on Human Papillomavirus and cervical cancer (24 January 2019)

The World Health Organization (WHO) has updated its fact sheet on Human Papillomavirus and cervical cancer.

Background Information:

Human papillomavirus (HPV) is a group of viruses that are extremely common worldwide.

There are more than 100 types of HPV, of which at least 14 are cancer-causing (also known as high risk type).

HPV is mainly transmitted through sexual contact and most people are infected with HPV shortly after the onset of sexual activity. HPV is sexually transmitted, but penetrative sex is not required for transmission. Skin-to-skin genital contact is a well-recognized mode of transmission.

Key Messages:

Cervical cancer is by far the most common HPV-related disease. Nearly all cases of cervical cancer can be attributable to HPV infection.

Cervical cancer is caused by sexually acquired infection with certain types of HPV.

Two HPV types (16 and 18) cause 70% of cervical cancers and precancerous cervical lesions.

There is also evidence linking HPV with cancers of the anus, vulva, vagina, penis and oropharynx.

How HPV infection leads to cervical cancer

Although most HPV infections clear up on their own and most pre-cancerous lesions resolve spontaneously, 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 infection persistence and development of cervical cancer

  • HPV type – its oncogenicity or cancer-causing strength;
  • immune status – people who are immunocompromised, such as those living with HIV, are more likely to have persistent HPV infections and a more rapid progression to pre-cancer and cancer;
  • coinfection with other sexually transmitted agents, such as those that cause herpes simplex, chlamydia and gonorrhoea;
  • parity (number of babies born) and young age at first birth;
  • tobacco smoking

Cervical cancer

Globally, cervical cancer is the fourth most frequent cancer in women (7.5% of all female cancer deaths). However, it is the second most common cancer in women living in less developed regions with an estimated 570 000 new cases in 2018 (84% of the new cases worldwide).

In 2018, approximately 311 000 women died from cervical cancer; more than 85% of these deaths occurring in low- and middle-income countries.

Symptoms of early stage cervical cancer may include:

  • Irregular blood spotting or light bleeding between periods in women of reproductive age;
  • Postmenopausal spotting or bleeding;
  • Bleeding after sexual intercourse; and
  • Increased vaginal discharge, sometimes foul smelling.

As cervical cancer advances, more severe symptoms may appear including:

  • Persistent back, leg and/or pelvic pain;
  • Weight loss, fatigue, loss of appetite;
  • Foul-smell discharge and vaginal discomfort; and
  • Swelling of a leg or both lower extremities.

Other severe symptoms may arise at advanced stages depending on which organs cancer has spread.

Diagnosis of cervical cancer must be made by histopathologic examination. Staging is done based on tumor size and spread of the disease within the pelvis and to distant organs.

Treatment depends on the stage of the disease and options include surgery, radiotherapy and chemotherapy.

Palliative care is also an essential element of cancer management to relive unnecessary pain and suffering due the disease.

Cervical cancer can be cured if diagnosed at an early stage.

Prevention and Control of Cervical cancer

In developed countries, programmes are in place which enable girls to be vaccinated against HPV and women to get screened regularly. Screening allows pre-cancerous lesions to be identified at stages when they can easily be treated. Early treatment prevents up to 80% of cervical cancers in these countries.

Comprehensive cervical cancer control includes

  • primary prevention (vaccination against HPV),
  • secondary prevention (screening and treatment of pre-cancerous lesions),
  • tertiary prevention (diagnosis and treatment of invasive cervical cancer) and palliative care.

who comprehensive cervical cancer 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.

HPV vaccination

There are currently 3 vaccines protecting against both HPV 16 and 18, which are known to cause at least 70% of cervical cancers. While two protect only against HPV 16 and 18, the third vaccine protects against three additional oncogentic HPV types, which cause a further 20% of cervical cancers. Given that the vaccines only protecting against HPV 16 and 18 also have some cross-protection against other less common HPV types which cause cervical cancer, WHO considers the three vaccines equally protective against cervical cancer. Two of the vaccines also protect against HPV types 6 and 11, which cause anogenital warts.

Clinical trials and post-marketing surveillance have shown that HPV vaccines are very safe and very effective in preventing infections with HPV infections.

Vaccines that protect against HPV 16 and 18 are recommended by WHO and have been approved for use in many countries.

HPV vaccines work best if administered prior to exposure to HPV. Therefore, WHO recommends to vaccinate girls, aged between 9 and 14 years, when most  have not started sexual activity.

The vaccines cannot treat HPV infection or HPV-associated disease, such as cancer.

WHO recommends vaccination for girls aged between 9 and 14 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.

Screening and treatment of pre-cancer lesions in women of 30 years and more is a cost-effective way to prevent cervical cancer.

Screening has to be linked to access to treatment and management of positive screening tests. Screening without proper management is not ethical.

There are 3 different types of screening tests that are currently recommended by WHO:

  • HPV testing for high-risk HPV types.
  • visual inspection with Acetic Acid (VIA)
  • conventional (Pap) test and liquid-based cytology (LBC)

For treatment of pre-cancer lesions, WHO recommends the use of cryotherapy and LEEP.

Useful Links:

Link to the updated fact sheet:

https://www.who.int/news-room/fact-sheets/detail/human-papillomavirus-(hpv)-and-cervical-cancer

Link to WHO’s Comprehensive Cervical Cancer Control guidance (English) [PDF] (2014):

https://www.who.int/reproductivehealth/publications/cancers/cervical-cancer-guide/en/

Link to WHO IARC Global Cancer Observatory site:

http://gco.iarc.fr

 

Advertisements

2 thoughts on “WHO updates fact sheet on Human Papillomavirus and cervical cancer (24 January 2019)

  1. John Brad

    Thanks for sharing the WHO update on cervical cancer. As an oncologist, we need such useful info for cancer treatments and early diagnosis. Keep us updated.

    Like

    Reply

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.