Cancer Expert Working Group on
Cancer Prevention and Screening (CEWG)
Recommendations on Prevention and Screening for Cervical Cancer
For Health Professionals

Local epidemiology
Cervical cancer was the seventh commonest cancer among
women in Hong Kong in 2018. A total of 582 new cases of cervical cancer
were recorded in the year, accounting for 3.4% of all new cancer cases inwomen.1 The age-standardised incidence rate (ASIR) of cervical cancer
was 8.4 per 100,000 standard populationa. The median age at diagnosis
was 54 years old and the age-specific incidence rates generally increase withage.

Being the eighth leading cause of cancer deaths among women in

2019, cervical cancer caused 162 deaths, accounting for 2.6% of all female
cancer deaths. 2 The age-standardised mortality rate (ASMR) of cervicalcancer was 2.1 per 100,000 standard population.a
衞生防護中心乃衞生署
轄下執行疾病預防及控制的專業架構
The Centre for HealthProtection is a
professional arm of the
Department of Health fordisease prevention
and controlaRates were standardised to the Segi’s world standard population (Segi, 1960).

2.

Both ASIR and ASMR of cervical cancer showed a downward

trend over the past three decades. Comparing with Asian countries, the latest
ASIR of cervical cancer for Hong Kong was lower than that of Japan, but slightly
higher than those of Korea and Singapore. While the latest ASMR for Hong
Kong was lower than those for Singapore and Japan, it was higher than those of
Korea and a number of developed Western economies.1,2,3

Risk factors

3.

Cervical cancer is caused by persistent infection with high-risk

human papillomavirus (HPV), with HPV-16 and 18 accounting for about 70% ofcervical cancer cases.

In Hong Kong, HPV-16, 18, 31, 33, 45, 52 and 58

accounted for about 90% of cases of cervical cancer. 4

About 90% of HPV

infections usually clear up within 2 years and a small proportion of persistentinfections would progress to cervical cancer in 15 to 20 years in women withnormal immune systems.5

4.

Risk factors for HPV acquisition/persistence or cervical cancer

include: 6,7,8,9,10,11,12,13(a) early first sexual intercourse(b) multiple sexual partners(c) tobacco use(d) chronic

immunosuppression,e.g.

HIV-infectedindividuals,

recipients of organ transplant(e) increasing parity(f) younger age at full term pregnancy(g) long term use of oral contraceptive pills for more than five years (therisk declined after use ceased, and by 10 or more years returned tothat of never users)2

(h) co-infection with sexually-transmitted diseases (such as chlamydia
infection)

5.

There is no evidence on increased risk of cervical intraepithelial

neoplasia (CIN) in women receiving cytotoxic chemotherapy for non-genitalcancers, estrogen antagonists such as tamoxifen, long term biologic agents.10

Primary prevention

6.

Primary prevention is an important strategy to lower the risk ofdeveloping cervical cancer.

The World Health Organization (WHO)recommends the introduction of HPV vaccination to national immunisation
programmes and prevention of cervical cancer is best achieved throughimmunisation of girls prior to sexual debut.14 In Hong Kong, eligible female
primary school students of suitable ages have been provided with HPV vaccine
under the Hong Kong Childhood Immunisation Programme (HKCIP) startingfrom the 2019/20 school year to prevent cervical cancer.15

However, since

HPV vaccines do not treat pre-existing HPV infection, nor do they offer a 100%
protection from cervical cancer, HPV vaccination does not replace cervicalcancer screening.4
7.

Other preventive measures to reduce the risk of HPV infection

include the practice of safe sex (such as avoid having multiple sexual partners
and use condoms) to reduce the chance of contracting HPV and other sexuallytransmitted diseases,16,17 as well as abstinence from tobacco smoking.18

Early detection

8.

Early stage of cervical cancer and pre-cancerous cell changes may

3

produce no symptoms at all. Common signs and symptoms of cervical cancer
include abnormal vaginal bleeding (for example, between periods, during or aftersex, and after menopause), vaginal discharge with foul smell, and discomfort orpain during sex. Women should visit doctors promptly if suspicious symptoms
develop.

Screening for general female population

9.

Screening can prevent cervical cancer by detecting and treating

pre-cancerous abnormalities of the cervix.
(a) Cervical cytology

10.

Cervical cytology, conducted by either conventional cytology (alsoknown as cervical smear or Pap smear) or liquid-based cytology (LBC), has beena primary screening strategy in Hong Kong. A systematic review conducted by
the U.S. Preventive Services Task Force established that LBC does not differ
from conventional cytology in sensitivity, specificity, or relative CIN detection.19
11.

According to a collaborative study of screening programmes ineight countries performed by the International Agency for Research on Cancer,
the percentage reduction in cumulative incidence in women aged 35-64, whohave been screened before age 35, is 93.5% when the interval between cervicalsmears is 1 year, 92.5% at 2 years, 90.8% at 3 years, 83.6% at 5 years and 64.1%
at 10 years, assuming 100% compliance.

Screening every one to two years

provides little additional protection compared with screening every three years.20(b) HPV testing

12.

HPV testing should only target at high-risk HPV types (e.g. HPV4

16, 18, 31, 33, 45, 52 and 58) as testing for low-risk HPV types has no clinicalrole in cervical cancer screening. Moreover, only clinically validated HPV tests
should be used since the performance characteristics vary among HPV tests.
Laboratory standard operating procedures and quality assurance programmes
should be in place for use of any HPV testing procedures.21

13.

Studies have shown that HPV testing has superior sensitivity andslightly lower specificity when compared with cervical cytology in detecting
CIN grade 2 or worse (CIN2+).22

There is also evidence suggesting that HPV

testing for high-risk types detected cervical precancerous lesions earlier thancytology.23,24,25,26 A pooled analysis of four European randomised controlled
trials (RCTs) indicated HPV-based screening as co-testing (i.e. both HPV testing
and cytology) was associated with 40% lower risk of cervical cancer whencompared with cytology. 27

In addition, studies found that extension of

screening interval to 5 years for HPV-based screening is scientifically soundbecause a baseline HPV-negative status was associated with lower cumulativerisk of CIN2+/CIN3+ over 2-3 rounds than baseline cytology-negative status,
demonstrating an extended period of protection against CIN2+/CIN3+
lesions.28,29,30

14.

Locally, the University of Hong Kong (HKU) has embarked on a

RCT to investigate the effectiveness of co-testing for cervical cancer screening
as compared to cytology alone in a sample of over 15,000 local Chinese women
aged 30-60. Published in 2020, the HKU study had findings consistent withoverseas RCT results and demonstrated that co-testing led to earlier detection ofclinically significant pre-invasive lesions.31 In the baseline screen, the CIN2+
detection was 2.5 times higher in the co-testing group compared to the cytology
group.

In the subsequent round 3 years later, there was a 77% reduction in

CIN2+ lesions. The total CIN2+ detection over 2 rounds were higher in the cotesting group.
5

15.

Screening with primary high-risk HPV testing as a stand-alone test

or co-testing was associated with more false-positive results and higher
colposcopy rates.31, 32

However, if HPV-positive results were triaged withcytology, the false-positive rates and colposcopy referral rates were similar tothat for cytology.32, 33 A second triage test such as cytology or HPV16/18
genotyping should be done to better predict which of these women would havea high risk of developing CIN2+ and hence need referral for colposcopy.21

16.

Moreover, studies have shown that women younger than 30 yearsof age screened with primary high-risk HPV testing or co-testing had higher
referral rates for colposcopy than women screened with cytology (2.3-13.1% vs.
1.9-4.7%).32 A modelling study suggested switching from cytology to high-risk
HPV testing at age 30 years yielded the most efficient harm to benefit ratio whencompared with switching at other younger ages using colposcopy as a proxy forharms. 34

Of note, HPV testing offers another benefit through opening thefeasibility of self-sampling.35
17.

In recent years, an increasing number of overseas countries like

Australia, the Netherlands, U.K. and U.S. implement or recommend HPV testing
as the main or one of the primary screening tests for cervical cancer.36,37,38,39,40
Economic analyses from Australia and the U.K. predicted that a switch fromcytology to HPV testing would be cost-effective in terms of its ability in reducing
cervical cancer incidence and mortality and is associated with substantially lower
annual healthcare cost in both HPV-vaccinated and unvaccinated cohorts.41,42
Local study on the cost-effectiveness of HPV testing is underway.

Screening for women at increased risk
18.

Some studies have shown that cervical cancer screening among6

persons with increased risk, such as HIV-positive women and renal transplant
recipients, was effective in reducing the risk of pre-cancerous lesions andcervical cancer mortality. 43 , 44

On the other hand, there is concern about

potential harms associated with detection of mild cervical abnormalities 45 , 46
which are common in younger age group, as the majority of which can be clearedon their own naturally. Although evidence on the benefit of cervical cancer
screening for the younger age group is limited and inconsistent,47,48 there may
be merit to screen women aged 21-24 with risk factors, based on individual risk
assessment by doctors.

Revised recommendations by CEWG
19.

After taking into consideration the local epidemiology, emerging

scientific evidence, local and overseas screening practices, the CEWG has
formulated the revised recommendations on cervical cancer screening whichwere endorsed by the Cancer Coordinating Committee at its 16th meeting on 18
June 2021. The revised recommendations for the local female population are
as follows(i) Women aged 25 to 64 who ever had sexual experience are recommended
to have regular cervical cancer screening.
(ii) For women aged 30 to 64, cervical cancer screening by cytology every
three years, after two consecutive normal annual screenings, continues tobe recommended. Owing to the potential higher sensitivity, earlier andincreased detection of precancerous lesions, better reduction in incidenceof precancerous lesions and longer screening intervals and feasibility ofself-sampling, HPV-based screening, either in the form of stand-alone
primary high-risk HPV testing or co-testing, for screening average-risk
women aged 30 years or above can be adopted as an alternative tocytology testing. Re-screening of HPV-negative cases is recommended
7

to be every five years.

Triage is necessary to limit the higher false-

positive rate and colposcopy rate associated with HPV-based testing and
the Guidelines for Cervical Cancer Prevention and Screening by the Hong
Kong College of Obstetricians and Gynaecologists provides references onrecommended means of triage.21(iii) For women aged 25 to 29, cervical cancer screening by cervical cytology
every three years, after two consecutive normal annual screenings,
continues to be recommended.
(iv) HPV testing should only target at high-risk HPV types (e.g. HPV-16, 18,
31, 33, 45, 52 and 58).
(v) Cost effectiveness of adopting primary high-risk HPV testing has been
well demonstrated in overseas’ programmes/studies. In view of absenceof local data on cost-effectiveness, further local study on costeffectiveness analysis is proposed.
Summary of Revised CEWG Recommendations on Cervical Cancer
Screening (June 2021)(a) For asymptomatic population at Average risk
Women aged

 Women aged 25 to 29 who ever had sexual experience

25 to 29 whoare recommended to have cervical cancer screening by

ever had sexual

cytology every three years after two consecutive normal

experienceannual screenings.

Women aged

 Women aged 30 to 64 who ever had sexual experience

30 to 64 whoare recommended to have cervical cancer screening by

ever had sexual(i)

experience

cytology every three years after two consecutive
normal annual screenings; or

8

(ii)

primary HPV testing every five years; or(iii)

co-testing every five years.

* clinically validated high-risk HPV testing should detect
high-risk HPV types (e.g. HPV- 16, 18, 31, 33, 45, 52 and58) in samples taken from cervix.
Women aged

 Screening may be discontinued in women aged 65 or

65 or above

above if routine screening within 10 years are normal.

who ever had Women at or above 65 years of age who have never had

sexualcervical cancer screening should be screened.

experience(b) For persons at Increased risk
Women aged

 Women aged 21 to 24 years who ever had sexual

21 to 24 who

experience and with risk factors for HPV

ever hadacquisition/persistence or cervical cancer are consideredsexualat increased risk. They may be screened by cytology

experience

every three years after two consecutive normal annual
screenings, depending on doctor’s assessment.

Others Other women at high risk of developing cervical cancer
may require more frequent screens based on doctor’s
assessment.

June 2021
The copyright of this paper belongs to the Centre for Health Protection, Department of Health, Hong
Kong Special Administrative Region. Contents of the paper may be freely quoted for educational,
training and non-commercial uses provided that acknowledgement be made to the Centre for HealthProtection, Department of Health, Hong Kong Special Administrative Region. No part of this paper may
be used, modified or reproduced for purposes other than those stated above without prior permission
obtained from the Centre.

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