Cervical cancer is caused by a very common virus, but it is easy to detect and there is a vaccination for it, writes Mia Malan
Cervical cancer is almost entirely preventable through regular screenings. Yet it is the most common cause of cancer-related death in Southern Africa. Here's a beginners' guide to the disease and how to protect yourself against it.
What is cervical cancer?
Cervical cancer is caused by the human papillomavirus. HPV is almost always transmitted through genital skin contact during sex; penetrative intercourse is not required and the virus can also be contracted during oral sex. HPV is therefore an extremely contagious virus, much more so than, for instance, HIV.
Professor Greta Dreyer of the University of Pretoria's gynaecological oncology unit says there are at least 30 types of HPV that affect the skin of the lower genital tract. About 15 of them are associated with cancer, of which HPV 16 and 18, 45 and 35 are the most common cancer-causing types in South Africa.
"More than half of the women diagnosed are between the ages of 35 and 55. It rarely occurs in women under 20 and only 20% of the infected women are more than 65 years of age," says the Cancer Association of South Africa.
Dr Yasmin Adam of Chris Hani Baragwanath Hospital's obstetrics and gynaecology department says South Africa has 5743 new cases of cervical cancer a year and 3027 annual deaths from the disease. These figures were published by the international cancer project Globocan. The numbers were extra-polated using the Zimbabwean cancer registry, as South Africa does not have an up-to-date cancer registry. Statistics South Africa estimates that 16.84-million South African women over the age of 15 are at risk of cervical cancer.
How does HPV cause cancer?
According to the United States government's Centres for Disease Control (CDC) HPV can cause normal cells on infected skin in the cervix to become abnormal. The US's National Cancer Institute explains that such cells grow in an uncontrolled manner because some of the proteins produced by HPV interfere with the normal functions of cells. Most of the time you cannot see or feel these cell changes.
Doctors refer to the damage that HPV infection causes as "lesions" that can range from "low-grade lesions" (not so dangerous) to "highgrade lesions" (more dangerous, as the virus has inserted its DNA into more cells) and even cancerous lesions.
In nine out of 10 cases, the body fights off HPV naturally and the infected cells and even the precancerous lesions can revert to normal. But when the body fails to do that, the lesions can progress to cancer. Only about half of even high-grade lesions progress to cervical cancer.
Symptoms can take years to appear because it is such a "slow-growing" cancer.
It's often only discovered at a late and painful stage. According to Dr Mary Gallenberg from the medical website mayoclinic.com, "it can take between 10 and 20 years from the time of an initial HPV infection until a tumour forms".
Who has HPV?
Dreyer says about 80% of all sexually active women and men in South Africa will contract HPV in their lifetime. Most people, however, don't know that they have the virus, as it is rarely accompanied by any symptoms. HPV will remain dormant or the infection will clear up naturally in nine out of 10 people.
Is HPV dangerous to men too?
Yes. According to the CDC, HPV can cause cancers of the penis, anus or back of the throat in men. Gay and bisexual men are about 17 times more likely to develop anal cancer than men who only have sex with women. HIV-infected men have a bigger chance of developing anal cancer because they have weaker immune systems. As with women, most men who contract HPV never develop any problems.
Why are HIV-infected women more likely to get cervical cancer?
The US's National Cancer Institute says HIV-infected women are five times more likely to develop cervical cancer.
HIV infection makes a woman's immune system less able to fight off HPV infection. South African data shows that HIV-positive women get cervical cancer at a much younger age than women who are HIV negative. Moreover, studies have demonstrated that women with HIV are more likely to smoke than HIV-negative women – smoking doubles a woman's chance of getting cervical cancer.
Why are black women the worst affected by cervical cancer?
Cervical cancer is the leading cause of cancer death among women in Southern Africa. It is almost entirely preventable if abnormal cells are detected at an early stage. Many black South African women, however, rely on the public health care system, which offers extremely limited access to screening through which such cells can be detected. This has resulted in black women being far less likely to access preventative technology.
What can you do to prevent yourself and your children from getting cervical cancer?
The National Cancer Institute in the US says the most reliable way to prevent HPV infection is to avoid any skin-to-skin oral, anal or genital contact with another person. Most adults, however, are sexually active. A mutually monogamous relationship with a partner who is not affected is likely to protect you against HPV. But, because of the lack of symptoms, "it is hard to know whether a partner who has been sexually active in the past is currently infected with HPV," says the institute. So, here's what you need to do:
1. Go for a regular screening test
Three types of screening tests are used. These include the well-known pap smear (which detects early cell changes that may progress to cancer), visual inspection of the cervix (using a light source and speculum to detect early changes in the surface colour of the cervix) and HPV testing (which detects the risk to develop cervical cancer by detecting infection with cancer-causing HPV types).
These screening options have different recommended intervals, accuracy levels and prices. Although a pap smear is the best known test, it needs frequent repeat testing. HPV testing has the ability to predict disease or the absence of disease further into the future and therefore does not require frequent repeat tests. For optimal protection a pap smear should be done at least once every three years whereas a negative HPV test should be repeated in five to 10 years.
In South Africa's private health sector, sexually active women generally go for regular pap smears – often up to once a year. The public health sector only provides three free pap smears in the lifetime of each woman: screening starts at the age of 30 and is done every 10 years until three have been done. It is estimated that this would reduce the incidence of cervical cancer by between 64% to 70%.
The acting manager of women's health at the health department, Dr Nat Khaole, says the government's goal is to have 70% of women over 30 screened by 2014. However, it's lagging far behind in its goals.
According to a recent study in the international journal PLOS Medicine, as well as research conducted by the cities of Johannesburg and Tshwane, each year, only between 2% and 4% of South African women using state hospitals has so far received one pap smear.
At this pace, South Africa would only have screened 40% of women by 2014 – less than half of what the government is aiming for. This would result in the majority of public sector cervical cancer patients only reaching doctors at a late stage of the disease when treatment is far less effective.
2. Consider an HPV test if the results of the screening test are abnormal
Having a screening test will not protect you if you do not know your test result or get treatment for your cancer risk. This is especially important if your screening test is done by a government clinic, which may not have the capacity to follow up with individual patients. Make sure you get your result and also ensure that you access treatment if needed.
An HPV test can determine whether you've contracted the virus and also which type. The HPV test will also be able to detect whether the virus has disappeared from your body after treatment.
3. Get your daughter vaccinated
There are two extremely effective HPV vaccines available on the market: Gardasil, produced by Merck, and Cervarix, manufactured by GlaxoSmithKline. Both vaccines protect against infections with cancer-causing HPV types 16 and 18. These vaccines work best if taken before having contracted HPV, that is, before becoming sexually active.
At between R500 and R1 000 a shot (three shots are needed per person), Cervarix and Gardasil are expensive and only available in the private sector in South Africa. The government is currently negotiating with both manufacturing companies to lower their prices in exchange for large purchase orders. It plans to vaccinate all girls aged 10. According to Khaole, a deal is likely to be struck within the next two years.
A University of Pretoria trial has shown that one out of three of the mothers or caregivers of 10-year-old girls who take them for HPV vaccinations are at high risk of cervical cancer. HPV vaccinations in the public sector could also present the opportunity of introducing screening among parents in order to prevent them from developing cervical cancer.
4. Stop smoking
According to the American Cancer Society, women who smoke are about twice as likely as non-smokers to develop cervical cancer.
5. Use a condom
Research has shown that condoms can reduce the transmission of HPV between sexual partners, but not completely: areas not covered by a condom can be infected by the virus.
Mia Malan works for the Discovery Health Journalism Centre at Rhodes University