Cervical Screening and HPV Vaccine

Cervical Cancer

Cervical cancer is a common cancer among women in Hong Kong. Nearly all cervical cancers are caused by persistent infection by high-risk Human Papillomavirus (hr-HPV) which are primarily transmitted through sexual contact. Most people who are infected by hr-HPV do not have symptoms and the infections will clear up on their own. However, persistent infection by hr-HPV can cause abnormal cervical cell changes (precancerous changes), which may subsequently progress to cancer.

Cervical Screening

All women who have ever had sexual experience should receive regular cervical screening, which can detect hr-HPV or early abnormal cervical cell changes. Timely treatment of precancerous changes can prevent the progression to cervical cancer. Cervical cancer screening options currently available include cervical cytology, HPV DNA test and Co-test (HPV DNA test with cervical cytology).

FPAHK Cervical Screening Tests

1. Co-test (HPV DNA testing + Liquid-based cytology)

Benefits: Co-test improves the sensitivity of cervical cancer risk assessment by detecting abnormal cervical cells and hr-HPV at the same time

Target: Recommended for women aged 30 or above who have ever had sexual experience

Sampling: Co-test is done by using the same liquid-based cell sample, there is no additional sampling required

Co-test Results:

HPV DNA Test Result

Cervical Cytology Result Recommendations*
Negative Negative Indicates normal result and a 5-year screening interval for Co-test is recommended
Positive Negative Refer for colposcopy or repeat Co-test after a recommended period depending on the genotyping result
Negative Positive Refer for colposcopy, or repeat Co-test after a recommended period depending on the severity of cervical abnormalities
Positive Positive Refer for colposcopy

*According to The Hong Kong College of Obstetricians and Gynaecologists (HKCOG) guideline on Cervical Cancer Prevention and Screening in 2016 

2. Cervical cytology (Liquid-based cytology)

Benefits: Cervical cytology detects early abnormal changes in cervical cells, including precancerous cells

Target: Women aged 25-64 who have ever had sexual experience and those aged 21-24 who are at increased risk for cervical cancer

Sampling: A healthcare provider inserts a speculum into the vagina and uses a soft brush to collect sample cells from the cervix, rinse them into a preservation solution. The sample is sent to a laboratory for processing. Reflex hr-HPV testing will be performed to triage ASCUS cases

Interpretation: Computer-assisted interpretation of liquid-based thin preparation cervical cytology

Cervical Cytology Result Recommendations
Negative Repeat cervical cytology every 3 years after two consecutive normal annual screenings
Positive Retest or further investigation such as colposcopy depending on the severity of cervical abnormalities

Frequently Asked Questions

What is HPV DNA test?

HPV DNA test detects high-risk HPV (hr-HPV) types that can cause cervical cancer or precancerous changes. In 2021, World Health Organization (WHO) recommended HPV DNA test as a first-choice screening method for cervical cancer prevention.

Which types of HPV can be tested by FPAHK’s HPV DNA test?

HPV is a common virus that has more than 200 subtypes, and about 40 of which infect the ano-genital area. HPV DNA test provided by the FPAHK is approved by the U.S. Food and Drug Administration for screening. The test detects 14 hr-HPV subtypes, including HPV-16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68. Among these, HPV-16 and HPV-18 cause 70% of cervical cancer.

Cervical cytology has been used for decades, why there is a change now?

Co-test improves the sensitivity of cervical cancer risk assessment by detecting abnormal cervical cells and hr-HPV at the same time. The Hong Kong College of Obstetricians and Gynaecologists (HKCOG) guideline on Cervical Cancer Prevention and Screening in 2016 had already embraced the use of co-test for cervical cancer screening. The Cancer Expert Working Group on Cancer Prevention and Screening (CEWG) of the Centre for Health Protection also recommended co-test as one of the cervical cancer screening methods. One local study demonstrated earlier detection of cervical cells abnormality by co-test, and reduction of cervical cancer risk through appropriate treatment.

Why is co-test NOT recommended for women under 30 years old?

The prevalence of HPV infection among these young women is high, but most of the infections are transient and will clear up on their own. It will cause unnecessary stress and overtreatment to these women if they are tested positive.

Is co-test 100% accurate?

All screening has its limitation and is not 100% accurate. Therefore, even if your previous cervical screening result is normal, you should watch out for symptoms of cervical cancer and see a doctor promptly if you have any symptoms. Women at increased risks should receive screening based on doctor’s assessment and recommendations.

Who should go for cervical screening?

All women aged 25 to 64, who have ever had sexual experience are recommended to have regular cervical screening irrespective of whether they are HPV vaccinated, single or married, have not had sex for years, reached menopause or have had sterilization. Those who started sex early should consult their doctor to see if they need to start screening earlier.

Do women who have received HPV vaccine need regular cervical screening?

The HPV vaccine protects against some but not all HPV types, and cannot cure existing HPV infection, so women who have received the HPV vaccine still needs regular cervical screening.

What are the risk factors for cervical cancer?

Risk factors for cervical cancer include sexual intercourse at an early age, multiple sexual partners, smoking, a weakened immune system, a high number of childbirths or young age at first pregnancy, long-term use of oral contraceptive pills for more than 5 years (but the risk level returns to normal after 10 years of stopping the pills), and history of sexually transmissible infections. Women at an increased risk should start cervical screening earlier or have more frequent screening, after doctor’s assessment.

HPV Vaccine

What is 9-in-1 HPV vaccine? How should the vaccine be given?

  • The 9-in-1 HPV vaccine contains Human Papillomavirus (HPV) 6, 11, 16, 18, 31, 33, 45, 52, 58 L1 protein. It prevents genital warts, premalignant genital lesions and cancers affecting the cervix, vulva, vagina and anus caused by HPV types included in the vaccine.
  • Based on the information from the vaccine’s manufacturer, the vaccine should be given within half a year. People who are 15 years old or above need 3 doses, after the first injection, the second injection will be given 2 months later and the third injection will be given after another 4 months. People who are 14 years old or younger only need two doses, so the first injection will be followed 6 months later by the second injection. Currently there is no evidence that further booster is needed.

Can Cervical Cancer be prevented by HPV Vaccine?

  • For girls and women aged 9 or above who have not started sexual activities, HPV vaccine can significantly reduce the chance of getting cervical cancer.
  • For women who have been sexually active, the effectiveness of HPV vaccine varies. They should discuss with their doctor first before deciding on having vaccination.
  • Vaccination is not 100 percent effective in preventing cervical cancer. No matter they have been vaccinated or not, all sexually active women should have regular cervical screening.

Does the vaccination cause any transient reactions? 

  • The safety of the HPV vaccine is widely accepted by many monitoring agencies in USA, Canada, Europe, and the World Health Organization. Transient reactions after injection include: pain and swelling at the injection site, skin redness or itching, fever, headache, etc.
  • If the problem persists, you should consult a doctor and tell the doctor about your recent vaccination. Please inform your doctor before injection if you have any of the following conditions: allergic reaction to yeast or vaccines; pregnancy; disease of the immune system; low platelet count; blood clotting problem causing continued bleeding after injection, injury or tooth extraction; and any fever or medication taken on that day.

How to prevent Cervical Cancer? 

  • Prevention of Cervical Cancer takes more than HPV vaccination. Avoid risky sexual behavior by maintaining a stable and monogamous relationship, using a condom every time, and do not smoke or drink alcohol, so that your own immune system can resist the virus.

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