Cervical cancer: HPV, screening and vaccination explained for women

1. Introduction

The cervix is the lower, narrow end of the womb that opens into the vagina. Cervical cancer begins when cells in the cervix grow out of control. MedlinePlus explains that it usually develops slowly, often passing through abnormal cells called precancers first ^[2]. WHO says precancers that are not treated cause about 95% of cervical cancers ^[1].

The World Health Organization (WHO) says cervical cancer is the fifth most commonly diagnosed cancer in women worldwide, with about 604,000 new cases and about 280,000 deaths in 2024. The highest rates are in low and middle income countries, which reflects unequal access to vaccination, screening and treatment ^[1].

2. Causes and risk factors

Almost all cervical cancer is caused by long-lasting infection with high-risk types of human papillomavirus (HPV) ^{[1, 2]}. HPV is very common. It spreads through close skin-to-skin contact, usually during sex, and most infected people have no symptoms ^[2]. The CDC notes that at least half of sexually active people will have HPV at some point, but few will develop cervical cancer ^[4]. The immune system usually clears the virus within one to two years. If it does not, the infection can last and slowly turn normal cells abnormal ^[2].

WHO says progression usually takes 15 to 20 years, but 5 to 10 years in people with weakened immunity ^[1]. Other factors that raise risk include ^{[1, 2]}:

• Living with HIV, or another reason for weak immunity
• Smoking
• Other sexually transmitted infections
• Many births or a young age at first pregnancy
• Use of hormonal birth control pills
• Obesity

3. Signs and symptoms

Precancers rarely cause symptoms, and early cancer often causes none ^{[1, 2]}. When symptoms do occur, WHO and MedlinePlus list ^{[1, 2]}:

• Unusual bleeding between periods, after sex or after menopause
• Increased vaginal discharge that is watery, blood-stained or has a strong smell
• Pelvic pain or pain during sex
• Later signs such as back or leg pain, swollen legs, tiredness, weight loss, or trouble passing urine or stool

These signs can have other causes, but they should always be checked.

4. Screening

Screening means testing healthy people to find problems before symptoms begin. Two tests are used, and both use cells collected from the cervix with a swab ^[2]:

• The Pap smear looks for abnormal cells.
• The HPV test looks for the high-risk HPV types that can cause cancer.

WHO recommends a high-performance HPV test every 5 to 10 years for women from age 30, and every 3 to 5 years from age 25 for women living with HIV. Its global strategy aims for at least two lifetime screens, by age 35 and again by age 45. WHO also says samples that women collect themselves are as reliable as those collected by a clinician ^[1]. Local programmes differ, so ask your doctor which test and schedule apply to you.

The NHS describes the appointment as usually taking about 10 minutes, with the test itself under 5. A nurse or doctor uses a smooth tube called a speculum to see the cervix and a soft brush to collect cells. The test usually does not hurt, but some people find it uncomfortable ^[3]. Tips from the NHS include wearing a skirt, bringing someone with you, asking for a smaller speculum and asking to stop at any time. Light spotting can follow and should stop within a few hours ^[3].

5. Treating early changes and cancer

WHO says treatment of precancers is simple, usually quick and effective at preventing cancer. Methods include heat or cold probes that destroy abnormal cells and procedures that remove a small area of tissue ^[1]. If cancer is found, treatment depends on health, how far it has spread and your wishes. Options include surgery, radiation therapy, medicines for cancer and support care ^{[1, 2]}. The CDC says cervical cancer found early is highly treatable ^[4].

6. Prevention

• HPV vaccination. WHO says girls aged 9 to 14 are the priority group for HPV vaccination, ideally before sexual activity. The vaccines protect against HPV types 16 and 18, which cause about 76% of cervical cancers, and the schedule depends on the national programme ^[1].
• Regular screening, with follow-up if anything abnormal is found ^{[1, 2]}. WHO notes screening still matters after vaccination ^[1].
• Not smoking ^{[1, 2]}.
• Condoms. Correct use lowers the chance of HPV infection but does not remove it completely ^[2].

7. Special groups

WHO advises that women living with HIV be screened earlier and more often, and that people with weakened immunity may need extra vaccine shots ^[1].

8. When to see a doctor

See a doctor if you have bleeding between periods, after sex or after menopause, unusual or foul-smelling discharge, or persistent pelvic pain ^{[1, 2]}. Also contact a doctor if you have heavy bleeding or spotting that does not stop after a few hours following a screening test ^[3]. Ask your doctor when to start screening and how often, and ask about vaccination for your daughters.

In an emergency, call your local emergency number (112 in India, 911 in the United States).

9. Conclusion

HPV vaccination, regular screening and treating early changes can help prevent cervical cancer. Do not wait for symptoms, because early changes rarely cause them. Your doctor will advise on the screening plan that is right for you.