Challenges to eradicate cervical cancer globally
- Experts have called for the worldwide eradication of cervical cancer, but this is not likely to happen for a long time
- Significant progress has been made to eliminate cervical cancer in developed countries
- The overwhelming burden of cervical cancer falls disproportionately on women in low- to middle-income countries (LMIC)
- LMIC have relatively low levels of awareness of cervical cancer, patchy prevent programs and limited treatment options
- Over 80% of cervical cancer cases and deaths occur in LMIC
- Cervical cancer is the fourth most common cancer in women worldwide
- In 2018 there were an estimated 680,000 new cases and 311,000 deaths from the disease worldwide
- Cervical cancer is caused by sexually acquired infection from high-risk strains of the human papilloma virus (HPV)
- The majority of women will be infected with HPV at some point in their life
- HPV also causes genital warts and cancers of the head and neck and is also linked to cancers of the anus, vulva, vagina, penis and oropharynx
- HPV vaccines protect against 70% of cervical cancers and about 90% of genital warts
- Regular screening is also recommended to reduce the incidence of cervical cancer
Challenges to eradicate cervical cancer globally
Cervical cancer is a killer disease, which only affects women. It affects women of all ages from schoolgirls to grandmothers, but it is significantly more prevalent between the ages of 30 and 45.
The cervix, also known as the neck of the womb, connects a woman's womb and her vagina.
Lancet study raises hope of eradicating cervical cancer
Research findings published in the June 2019 edition of The Lancet suggest that HPV vaccination, which has been available to adolescent girls in wealthy developed countries since 2007, has led to a dramatic reduction in the number of HPV infections, precancerous cervical lesions and anogenital warts and provides hope of eradicating cervical cancer. Marc Brisson, Professor in the Department of Social and Preventative Medicine, Laval University, Canada, who led the research - a meta-analysis of over 65 former studies covering 60m people - said: "We will see reductions [in cervical cancer] in women aged 20-30 within the next 10 years, and eradication of the disease [defined as <4 cases per 100,000] might be possible if sufficiently high vaccination coverage can be achieved and maintained". Over the past two decades, the incidence rates of cervical cancer in developed countries have fallen significantly, and between 1955 and 1992, the incidence rate of the disease decreased 70% in the US. These falls are attributed to effective nationwide screening.
Epidemiology
Cervical cancer is the fourth most common cancer in women worldwide and second for women between 15 and 44. In 2018 there were an estimated 680,000 new cases and 311,000 deaths from the disease worldwide. The overwhelming majority of cases are caused by two specific strains of the human papilloma virus (HPV). HPV infection and early cervical cancer typically do not present noticeable symptoms, and cervical cancer may take 20 years or longer to develop after an HPV infection. The overwhelming global burden of the disease falls disproportionately on women in low- to middle income countries (LMIC). There is a significant and growing gap in the incidence and mortality rates of cervical cancer between developed nations and LMIC. Despite international efforts, it seems unlikely that this gap will be narrowed in the medium term.
In this Commentary
This Commentary describes the spread of HPV, the vaccines developed to prevent infection from specific high-risk strains of the virus and recommended vaccination regimens. We describe the nature and significance of complementary screening programs and present evidence to suggest that women who fail to get screened are more likely to contract cervical cancer in later life than women who are screened. HPV vaccination programs are more prevalent in developed economies and are associated with a significant reduction in the incidence rates of cervical cancer. This suggests that the battle to eliminate cervical cancer is being won in some wealthy developed nations. Australia is positioned to become the first country in the world to eliminate cervical cancer. Despite substantial global efforts to reduce the incidence rates of cervical cancer, the gap in preventing, diagnosing and treating the disease between wealthy nations and LMIC is significant and growing. We conclude by suggesting that to eradicate cervical cancer, screening and prevention programs must be linked to easily accessible and effective treatment.
The spread of HPV
Over 70% of cervical cancer is caused by two high-risk strains of HPV. Most women will contract HPV at some stage during their life, but this usually clears-up on its own without the need for any treatment. HPV is most commonly spread during vaginal, anal or oral sex. The virus can be passed even when an infected person has no signs or symptoms. If you are sexually active you can get HPV, even if you only have sex with one partner. Notwithstanding, the risk increases with the number of new sexual partners and their sexual histories. You also can develop symptoms years after you have sex with someone who is infected. This makes it hard to know when you first became infected.
HPV vaccines
The US Food and Drug Administration (FDA) has approved three vaccines, which prevent infection with disease-causing HPV types. These are Gardasil, Gardasil 9 and Cervarix. All three vaccines prevent infection with HPV types 16 and 18 in women who have not already been infected by these types. These are two high-risk HPV’s that cause about 70% of cervical cancers and an even higher percentage of some of the other HPV-caused cancers. Gardasil also prevents infection with HPV types 6 and 11, which cause 90% of genital warts. Gardasil 9 prevents infection with the same four HPV types, plus five additional cancer-causing types.
About 79m Americans are currently infected with HPV, with roughly 14m people becoming newly infected in the US each year. In the UK, HPV is present in one in three people and 90% of individuals will come into contact with some form of the virus in their lifetime. About 80% of sexually active people are infected with HPV at some point in their lives, but most people never know they have the virus. Whitfield Growdon, a surgical oncologist at the Massachusetts General Hospital and professor at the Harvard University Medical School describes the HPV vaccination as, “one of the most meaningful interventions for reducing cervical cancer”; see video below.
About 79m Americans are currently infected with HPV, with roughly 14m people becoming newly infected in the US each year. In the UK, HPV is present in one in three people and 90% of individuals will come into contact with some form of the virus in their lifetime. About 80% of sexually active people are infected with HPV at some point in their lives, but most people never know they have the virus. Whitfield Growdon, a surgical oncologist at the Massachusetts General Hospital and professor at the Harvard University Medical School describes the HPV vaccination as, “one of the most meaningful interventions for reducing cervical cancer”; see video below.
Who should get vaccinated?
All girls and boys aged between 11 and 12 should get the HPV vaccination. Every year in the US, over 13,000 males contract cancers caused by HPV. Catch-up HPV vaccines are recommended for girls and women through the age of 26, and for boys and men through the age of 21, if they did not get vaccinated when they were younger. HPV vaccination is also recommended for the following people, if they did not get vaccinated when they were younger: (i) young men who have sex with men through the age of 26, (ii) young adults who are transgender through the age of 26 and (iii) young adults with certain immunocompromising conditions (including HIV) through the age of 26.
Early cervical cancer is asymptomatic
Because early cervical cancer is asymptomatic, it is important for women to have regular Papanicolaou (Pap) smears - also called Pap tests - to detect any precancerous changes in the cervix that might lead to cancer. This is in addition to the HPV vaccination. In England women are invited to have Pap smears every three years between the ages of 25 and 49, when rates of cervical cancer are at their peak, and every five years between 50 and 65. Other international screening guidelines recommend that women aged 21 to 29 have a Pap smear every three years. Women aged 30 to 65 are advised to continue having a Pap test every three years, or every five years if they also combine it with an HPV DNA test. Women over 65 can stop testing if they have had three consecutive normal Pap tests, or two HPV DNA and Pap tests with no abnormal results.
The HPV DNA test determines the most likely cause of cervical cancer by looking for pieces of DNA in cervical cells and is recommended for women over 30 and not for women under 30. This is because women in their 20s tend to be more sexually active and therefore are more likely (than older women) to have an HPV infection that will go away on its own. Results of an HPV DNA test carried out on a woman in her 20s is not as significant as in and older woman and also may be confusing. The HPV DNA test can also be used in women who have slightly abnormal Pap test results to find out if they might need more testing or treatment.
What is a Pap smear test?
Diagnostic tests for cervical cancer
The expansion of screening programs for cervical cancer in LMIC is only part of the answer to closing the gap with developed nations and eradicating cervical cancer globally. It is imperative that screening is linked to increased access to effective treatment for women with cervical cancer, particularly in its early stages when it is still curable. In LMIC there is often not only reduced access to preventive HPV vaccines and screening, but limited access to treatment and trained personnel. Notwithstanding, there is evidence to suggest that, in LMIC less-invasive and less–resource-intensive treatment options can be effective and are increasingly being made available.
The HPV DNA test determines the most likely cause of cervical cancer by looking for pieces of DNA in cervical cells and is recommended for women over 30 and not for women under 30. This is because women in their 20s tend to be more sexually active and therefore are more likely (than older women) to have an HPV infection that will go away on its own. Results of an HPV DNA test carried out on a woman in her 20s is not as significant as in and older woman and also may be confusing. The HPV DNA test can also be used in women who have slightly abnormal Pap test results to find out if they might need more testing or treatment.
The Pap smear/test
The Pap smear or Pap test is a method of cervical screening used to detect potentially precancerous and cancerous processes in your cervix. During the routine procedure, cells from your cervix are gently scraped away and then examined for abnormal growth. Abnormal findings are often followed-up by more sensitive diagnostic procedures and if warranted, by interventions that aim to prevent progression to cervical cancer. Detecting cervical cancer early with a Pap smear significantly increases the chances of a cure. A Pap smear can also detect changes in your cervical cells, which suggest you might develop cancer in the future. In the two videos below Growdon describes the Pap smear and other tests for diagnosing cervical cancer.
What is a Pap smear test?
Diagnostic tests for cervical cancer
Women failing to have the Pap test are 6-times at greater risk of cervical cancer
There is evidence to suggest that women over 50 who fail to have a regular Pap smear have a much higher risk of developing cervical cancer compared with other women the same age who have a history of regular screening. Research carried out by Cancer Research UK and reported in 2014 investigated the utility of regular cervical cancer screening after 50, and whether 64 was an appropriate age to stop screening and concluded “yes” and “yes”. The study compared the screening history of 1,341 women between 65 and 83 in England and Wales who were diagnosed with cervical cancer over a five-year period, with 2,646 women of the same age without the disease. Findings suggest that women who did not attend screening tests were six times more likely to develop cervical cancer between 65 and 83 compared with women that did.
Australian the first country to eradicate cervical cancer
Australia is well positioned to become the first country in the world to eradicate cervical cancer. This is largely due to national vaccination and screening programs, which could see the disease effectively eliminated as a public health issue within the next two decades. In 2007, Australia launched a national publicly-funded school immunisation program to reduce HPV, which complemented a national cervical cancer screening program that was launched in the 1990s. These have been shown to reduce the incidence of cervical cancer and significantly increase early diagnosis when the disease is curable.
A research paper about the Australian initiative published in the January 2019 edition of The Lancet Public Health concludes that, “the annual incidence of cervical cancer in Australia is likely to decrease to fewer than six new cases per 100 000 women by 2020 (range 2018–22) and to fewer than four cases per 100 000 women by 2028 (2021–35). The annual incidence of cervical cancer could decrease to one new case per 100 000 by 2066 (2054–77) if the existing HPV-based screening program continues in cohorts who are offered the nonavalent vaccine”; [a nonavalent vaccine works by stimulating an immune response against nine different antigens, such as nine different viruses or other microorganisms]. According to Suzanne Garland, Professor and Clinical Director of Microbiology and Infectious Diseases at the Royal Women’s Hospital, Melbourne, Australia, who led the research, “within 40 years the number of new cases of cervical cancer [in Australia] is projected to drop to just a few”.
A research paper about the Australian initiative published in the January 2019 edition of The Lancet Public Health concludes that, “the annual incidence of cervical cancer in Australia is likely to decrease to fewer than six new cases per 100 000 women by 2020 (range 2018–22) and to fewer than four cases per 100 000 women by 2028 (2021–35). The annual incidence of cervical cancer could decrease to one new case per 100 000 by 2066 (2054–77) if the existing HPV-based screening program continues in cohorts who are offered the nonavalent vaccine”; [a nonavalent vaccine works by stimulating an immune response against nine different antigens, such as nine different viruses or other microorganisms]. According to Suzanne Garland, Professor and Clinical Director of Microbiology and Infectious Diseases at the Royal Women’s Hospital, Melbourne, Australia, who led the research, “within 40 years the number of new cases of cervical cancer [in Australia] is projected to drop to just a few”.
The two worlds of cervical cancer
Global efforts to reduce the incidence rates of cervical cancer have focused on HPV vaccination and the Pap test. Although experts are optimistic about eliminating cervical cancer in developed nations, which have advanced healthcare systems and extensive HPV vaccination, screening and treatment programs, they are significantly less sanguine about eradicating the disease in LMIC where there are relatively low levels of awareness of cervical cancer, a dearth of preventative strategies, limited expertise and a narrow band of treatment options. This results in the disease being identified late when it is at an advanced stage, which leads to higher rates of morbidity and death. Indeed, 85% of all cases and cervical cancer deaths occur in LMIC, where the death rate is 18 times higher than in wealthy nations.
Cervical cancer a challenge for LMIC
The gap in preventing, diagnosing and treating cervical cancer between wealthy nations and LMIC is described in a paper published in the November 2017 edition of Gynecologic Oncology Reports and suggests that, “Developing countries continue to bear a disproportionate percentage of the global cervical cancer burden. Investigations into the growing gap in incidence and mortality between developed nations and LMIC have cited persistent financial, infrastructural and educational limitations as key drivers. Pervasive lack of access to both preventative and definitive care has left a substantial portion of cervical cancer patients with minimal options for disease management”.
WHO strategy to eliminate cervical cancer
Recognising this disparity, in 2018, the Director-General of the World Health Organization (WHO) announced a call to action for the eradication of cervical cancer as a public health problem. In January 2019, the Executive Board of the WHO requested the Director General to develop a draft strategy to accelerate cervical cancer elimination, with clear targets for the period 2020 - 2030.
Vaccination and screening must be linked to effective therapies
The expansion of screening programs for cervical cancer in LMIC is only part of the answer to closing the gap with developed nations and eradicating cervical cancer globally. It is imperative that screening is linked to increased access to effective treatment for women with cervical cancer, particularly in its early stages when it is still curable. In LMIC there is often not only reduced access to preventive HPV vaccines and screening, but limited access to treatment and trained personnel. Notwithstanding, there is evidence to suggest that, in LMIC less-invasive and less–resource-intensive treatment options can be effective and are increasingly being made available.
Late presentation of cervical cancer in LMIC
Women from LMIC generally seek treatment for cervical cancer only after the presentation of symptoms when the disease is advanced and challenging to treat. Also, they often lack awareness of the disease and ways to prevent it. Further, in some regions of the world, cultural norms and myths about cervical cancer pose additional barriers to prevention. Despite such obstacles, the disease can be prevented at low cost by healthcare providers employing relatively simple techniques to screen women for precancerous conditions and treat abnormal tissue early. Among the most promising low cost and low-tech screening alternatives to the Pap smear, is visual screening, which only requires either simple vinegar or iodine solutions and the eye of a trained healthcare provider to spot abnormal tissue.
Screening linked to effective therapy
Increasingly, these simply tests are being linked with effective treatment. Increasingly, in LMIC relatively cheap and simple therapies are being used to either destroy or remove abnormal cervical tissue, depending on the severity, location and size of the affected area. Two such procedures include cryotherapy and loop electrosurgical excision procedure (LEEP). The former uses extremely low temperatures to destroy abnormal tissue and requires no electricity. The latter involves using a thin wire to remove lesions in the affected area. While this procedure requires more medical equipment than cryotherapy, it allows tissue to be removed for analysis, reducing the possibility that advanced cancer will go unnoticed. Although many LMIC have had cervical cancer prevention programs and simple treatment strategies in place for some time, some have failed to reduce death rates of the disease.
Radiotherapy and cervical cancer in LMIC
Research findings published in the May 2019 online edition of The Lancet Oncology suggest that the availability of radiotherapy in LMIC (where gross national income is <US$12,000 a year) would generate millions of productive life years and billions of dollars in economic benefits for the patients' families and communities. The study suggests that implementing a 20-year strategy for radiotherapy to treat cervical cancer in LMIC between 2015 and 2035, in parallel with an HPV vaccination program, would save the lives of some 9.4m women and provide a net benefit to economies of US$151.5bn as a direct result of women living longer and more productive lives.
According to Danielle Rodin, lead author and Radiation Oncologist at the Princess Margaret Cancer Centre, University of Toronto, Canada, "Vaccination is hugely important, but we can't neglect the millions of women who are contracting cervical cancer and dying in pain without access to treatment. These are women who have curable cancers: even advanced cervical cancer can be cured with radiotherapy. The possibility exists to make this treatment universally available". Radiation therapy makes small breaks in the DNA inside cells. This stops cancer cells from growing and dividing and causes them to die. Unlike cisplatin therapy, [an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy], which usually exposes the whole body to cancer-fighting drugs, radiation therapy is usually a local treatment.
According to Danielle Rodin, lead author and Radiation Oncologist at the Princess Margaret Cancer Centre, University of Toronto, Canada, "Vaccination is hugely important, but we can't neglect the millions of women who are contracting cervical cancer and dying in pain without access to treatment. These are women who have curable cancers: even advanced cervical cancer can be cured with radiotherapy. The possibility exists to make this treatment universally available". Radiation therapy makes small breaks in the DNA inside cells. This stops cancer cells from growing and dividing and causes them to die. Unlike cisplatin therapy, [an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy], which usually exposes the whole body to cancer-fighting drugs, radiation therapy is usually a local treatment.
According to the 2019 Lancet Oncology study, HPV vaccination would result in a 3.9% reduction in cervical cancer incidence over the 20-year study period; assuming a best-case scenario of vaccinating every 12-year-old girl in the world starting in 2014. By 2072, when the first vaccinated cohort reaches 70, there would be a 22.9% reduction in incidence, still leaving 41.6m in need for therapy over that time period.
“We know that when administered together (chemoradiation) you can give lower doses of both and get a better kill-rate on the tumour. This is now the backbone of cervical cancer therapy”, says Growdon; see video below.
“We know that when administered together (chemoradiation) you can give lower doses of both and get a better kill-rate on the tumour. This is now the backbone of cervical cancer therapy”, says Growdon; see video below.
Abu Dhabi’s endeavours to reduce cervical cancer
For some years, experts have discussed religious and cultural barriers to cervical cancer screening and drew attention to the relatively low levels of cervical cancer awareness and screening for women in Middle Eastern Arab countries. Meta-analysis of cervical cancer studies conducted in Arab countries between January 2002 and January 2017 and published in the December 2017 edition of Nursing & Health Sciences, suggest that in Arab speaking countries there tends to be, “low knowledge of and perceptions about cervical screening among Arab women, the majority of whom are Muslim. Factors affecting the uptake of cervical cancer screening practices were the absence of organized, systematic programs, low screening knowledge among women, healthcare professionals' attitudes toward screening, pain and embarrassment, stigma, and sociocultural beliefs”.
The success of HPV vaccination in Abu Dhabi and the UAE
Notwithstanding, there are signs that this is changing. Leading such changes is Abu Dhabi of the United Arab Emirates (UAE). Over a decade ago, a mandatory free HPV vaccination program for school girls was introduced by Abu Dhabi’s Ministry of Health and Prevention and extended in 2013 to include women between 18 and 26. Also, the Ministry recommends that woman aged 25 to 65 years get a Pap smear every three to five years. Since 2018, HPV vaccinations have been provided free and compulsory for all school girls in Dubai and the Northern Emirates following a campaign to raise awareness.
Although the UAE is among the few countries to have relatively low incidence rates of cervical cancer, the disease still ranks as the third most frequent cancer among women in the UAE and the third most frequent cancer among women between 15 and 44. Estimates suggest that every year, 93 women are diagnosed with cervical cancer and 28 die from the disease in the UAE. Although Abu Dhabi is successfully leading the fight against cervical cancer and provides a roadmap for others to follow, the incidence of cervical cancer in the Middle East generally is expected to more than double by 2035 (>33,000 cases) and be responsible for more than 18,000 deaths. In some countries including Morocco and Saudi Arabia, low societal awareness and relatively low levels of screening results in about one in four women with HPV.
Although the UAE is among the few countries to have relatively low incidence rates of cervical cancer, the disease still ranks as the third most frequent cancer among women in the UAE and the third most frequent cancer among women between 15 and 44. Estimates suggest that every year, 93 women are diagnosed with cervical cancer and 28 die from the disease in the UAE. Although Abu Dhabi is successfully leading the fight against cervical cancer and provides a roadmap for others to follow, the incidence of cervical cancer in the Middle East generally is expected to more than double by 2035 (>33,000 cases) and be responsible for more than 18,000 deaths. In some countries including Morocco and Saudi Arabia, low societal awareness and relatively low levels of screening results in about one in four women with HPV.
Takeaways
As cervical cancer screening and prevention programs have been growing and extending their reach, so increases the need to provide access to effective treatment. Despite growing awareness of the disease and global efforts to increase availability of appropriate resources, cervical cancer remains prevalent particularly in LMIC where effective treatment has not become widespread. In many LMIC, the default option is often to do nothing, which results in certain death. Researchers and policy makers should consider focusing their activities on how to best to reconcile the use of existing resources with the expected impact on the quantity and quality of life. Although gaps in oncological resources and barriers to treatment still exist, the good news is that there is increased political will and international attention to improve access to safe and effective treatment of cervical cancer. Notwithstanding, eradicating the disease globally appears to be more of a theoretical possibility than a medium term reality.
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