Cervical cancer is the fourth most frequent cancer in Malaysian women, and the second most frequent in women between 15 and 44 years of age.
The current estimates are that 1,740 women are diagnosed annually with cervical cancer, and 991 die from the disease.
Data from the Malaysian cancer registry indicates that the lifetime risk of cervical cancer is one in 154 for all women.
More specifically, it is one in 207 for Malay women, one in 132 for Chinese women, and one in 162 for Indian women.
The percentage diagnosed at late stages (stages 3 and 4) was 47.1%.
HPV infection and vaccines
About 1% of women in the general population are estimated to harbour cervical human papilloma virus (HPV) types 16 or 18 at any given time.
To put this in context, 88.7% of invasive cervical cancers are attributed to HPV 16 or 18.
Other HPV types involved in invasive cervical cancer are types 52, 58, 45, 33, 56, 39, 59 and 31 in descending order of frequency.
HPV is also found in cancers of the vulva and vagina in women; cancer of the penis in men; and cancers of the anus, oropharynx, oral cavity and larynx in both women and men.
Persons infected with one HPV type may be co-infected or subsequently infected with other HPV types.
The first HPV vaccine was made available in 2006 and has evolved since then.
There are three HPV vaccines currently available in Malaysia.
They are a bivalent vaccine, a quadrivalent vaccine and a 9-valent vaccine.
All three vaccines protect against HPV types 16 and 18, and can be administered to both males and females aged nine to 45 years of age.
Safety and effectiveness
Two Cochrane reviews published last November reported that HPV vaccination is safe and dramatically lowers the risk for cervical cancer.
One review addressed the impact of HPV vaccination at the population level on cervical cancer and other HPV-related cancers.
It included 225 studies that involved more than 132 million people.
The studies included 177 of females only, 11 of males only and 37 of both males and females.
Studies of 4.4 million females found a reduced risk of cervical cancer following HPV vaccination in the long term (risk ratio 0.37).
There was a greater risk reduction in younger people, i.e. those vaccinated at or before 16 years of age had an 80% reduced risk of cervical cancer (risk ratio 0.20).
There was evidence from 47 studies that HPV vaccination reduced the incidence of anogenital warts.
The pooled impact of HPV vaccination on rates of anogenital warts was a reduction of 47% in the medium term (risk ratio 0.53) and 53% in the long term (risk ratio 0.47)
There was evidence for the effect of HPV vaccination on rare conditions that take much longer to develop like adenocarcinoma in situ, other pre-cancer lesions and other HPV-related cancers e.g. vaginal, vulval, anal and penile cancer.
However, there were fewer studies on these outcomes.
With regard to specific adverse events that are commonly mentioned in social media, it was found that: “Across a range of study designs, HPV vaccination was not associated with an increased risk of postural orthostatic tachycardia syndrome, chronic fatigue syndrome/myalgic encephalomyelitis, paralysis, complex regional pain syndrome, premature ovarian failure, infertility or sexual activity (all moderate-certainty evidence).
“There was evidence that suggests HPV vaccination was not associated with an increased risk of Guillain-Barré syndrome (low-certainty evidence).”
More importantly: “HPV vaccination did not increase sexual activity.”
The review concluded that HPV vaccination is safe and reduced the risk of cervical cancer dramatically.
The authors stated that: “There are now long-term outcome data from different countries and from different study designs that consistently report a reduction in the development of high-grade CIN [cervical intraepithelial neoplasia, i.e. precancerous cells] and cervical cancer in females vaccinated against HPV in early adolescence.
“Data show that there is greater benefit to vaccinating younger adolescents prior to becoming sexually active.
“There is evidence that HPV vaccination does not increase the risk of the most common adverse events reported on social media.”
The other Cochrane review reported on 60 clinical trial data from around the world involving 157,414 participants.
Most of the trials lasted for at least 12 months.
The studies focused on the shorter-term outcomes, but were not long enough to provide data about the prevention of cancers, in contrast to the population studies.
The findings were:
> In 15 to 25-year-old females, there was a reduction in high grade cervical precancer (CIN2+) irrespective of HPV type after six years (risk ratio 0.70) and a larger reduction in CIN2+ from vaccine-matched HPV types after six years (risk ratio 0.40).
> In 15 to 25-year-old females, there was a slight reduction in high-grade vulval or vaginal precancer.
> In people aged 15 to 25 years, there was little to no difference in high-grade anal or penile pre-cancer in the short term.
> HPV vaccines reduced the risk of anogenital warts and the number of people aged 15 to 25 years needing treatment for possible early-stage HPV-related cancers.
> In an analysis of serious adverse events in 39 studies across all vaccine types involving 97,272 participants, there was little to no difference in the HPV vaccine groups, compared with the control group at up to 72 months follow-up (risk ratio 0.99).
In summary, there is a large body of evidence in both reviews of the safety and efficacy of HPV vaccines.
Our vaccination programme
It is important to vaccinate before first exposure to HPV infection.
The Cochrane reviews support such early vaccination.
In general, studies have found that that cervical cancer protection is less when an HPV vaccine was given after the age of 16 years.
However, it does not detract from the fact that the benefits of the HPV vaccine are still present for older teens, adults or a sexually-active young person as they would not have been exposed to all the HPV types that vaccination protects against.
The Health Ministry introduced its free HPV vaccination programme in 2010, targeting Form 1 girls (aged 13 years).
The initial uptake was high, but decreased substantially during the Covid-19 pandemic.
The first dose coverage in girls above 15 years dropped from 82% in 2020 to 14% in 2021, before improving to 39% in 2022.
This year, the Health Ministry is changing its target from Form 1 to Year 6 girls (aged 12 years).
The National Population and Family Development Board (LPPKN) provides free vaccination to selected young women.
The HPV vaccine is also available at private healthcare facilities.
There are currently 42 countries with a gender-neutral vaccination policy, in that both males and females are vaccinated against HPV.
The case for vaccinating boys is reinforced by the fact that men have a poorer immune response to HPV infection compared to women.
As such, gender neutral vaccination provides much greater levels of protection for everyone.
Path to elimination
A comparison of the cost of HPV vaccination to that of treating cervical cancer is synonymous with comparing an ounce of prevention (HPV vaccine) with a pound of treatment (cervical cancer).
A modelling study done by Universiti Malaya consultant obstetrician and gynaecologist Prof Dr Woo Yin Ling, Australian Centre for the Prevention of Cervical Cancer executive director and anatomic pathologist Prof Dr Marion Saville and Australia’s The Daffodil Centre research fellow Dr Adam Keane stated the following:
“If the current vaccination programme were to continue as is, Malaysia could eventually eliminate cervical cancer by the year 2066-2079, saving over 10,000 lives by 2070.
“The introduction of HPV screening would nearly double the number of lives saved over the next half-century and is cost-effective, compared with vaccination alone.”
If the Health Ministry changes to a gender-neutral policy and adopts HPV screening with a digital registry, cervical cancer and other HPV-related cancers could be eliminated much earlier with more lives saved – food for thought for policymakers.
In short, the HPV vaccine is one of the most efficacious vaccines ever invented.
The focus on any discussion should be on future cancer prevention, not sex.
Dr Milton Lum is a past president of the Federation of Private Medical Practitioners Associations and the Malaysian Medical Association. For more information, email starhealth@thestar.com.my. The views expressed do not represent that of organisations that the writer is associated with. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
