Tens of thousands of women’s lives could be saved worldwide after South African researchers confirmed the success of a novel way of preventing cervical cancer.
Researchers from the University of Cape Town have proved the effectiveness of a quick method to ”screen and treat” women to prevent them from developing the disease, using acetic acid — the main ingredient in vinegar.
The procedure can easily be applied in resource-poor settings, because it does not involve expensive and time-consuming laboratory procedures.
Globally cervical cancer is a disease of poverty, and one of the two most common cancers among black women in South Africa. More than 80% of the 240 000 deaths from cervical cancer a year occur in less developed countries where women lack access to specialised laboratory screening — the ”pap” (papanicolous) smear that has dramatically cut the incidence of the disease among wealthier woman.
Cervical cancer is a slow-growing malignancy, taking an average of 10 years to develop from the first pre-cancerous abnormal cells. It is also one of the easiest cancers to prevent by burning off the pre-cancerous cells at the neck of the uterus — and that is normally the end of it.
More than 6 500 women aged between 35 and 65, who had never had a pap smear, volunteered for the University of Cape Town study in Khayelitsha, funded by the Bill and Melinda Gates Foundation. About half were married and 12% HIV-positive.
They were randomly divided into three groups. In the first, the participants were tested for Human Papilloma virus (HPV) using a DNA molecular test, while those in the second were given an internal examination involving a visual inspection after washing the cervix with acetic acid. If abnormal cells are present, they show as a white lesion.
Women who got a positive test result in either test were treated at a primary care clinic by a nursing sister using cryotherapy, which destroys the cervical cells by freezing them to a depth of 5mm.
The third group formed the control, where treatment was delayed for six months regardless of the result of the acetic acid or HPV test. A longer delay was considered unethical.
The trial showed that both acetic acid and HPV DNA tests picked up pre-cancerous conditions, allowing for early treatment to forestall the development of cancer.
The results of the two-year study are reported in the November 2 edition of the Journal of the American Medical Association, a respected international peer review journal.
Led by Lynette Denny, of UCT’s obstetrics and gynaecology department, the local team worked with United States researchers. Denny has previously pioneered the acetic acid method of detecting pre-cancerous lesions on the cervix.
The Cape Town team also found that burning off pre-cancerous cells did not appear to heighten the risk of contracting HIV while the cervix was healing.
About 15% of cancers are known to be virally induced, and cervical cancer is one of them. Persistent infection of the cervix by certain types of the HPV is a necessary, although not sufficient, cause of cervical cancer. It is thought that up to 80% of sexually active young adults will have a transient HPV infection during their lifetime, but in some women the infection becomes persistent and can become cancerous.
Key to this transition are factors that weaken the immune system, including co-infection with herpes or chlamydia, smoking and possibly vitamin A deficiency. Risk factors for women also include an early sexual debut and higher numbers of sexual partners.
Co-infection with HIV also appears to increase the persistence of HPV, and to increase the speed at which it develops into cervical cancer.
Trial vaccines have proved highly successful against the most common forms of HPV. But while vaccines may prevent new cases, they do not help infected women. A cost-benefit analysis suggests that the cost of preventing a case of cervical cancer is about R600, while treating it costs about R60 000.
The high levels of cervical cancer among black South Africans result from both lack of access to health care and possible lack of knowledge. In the 1990s it was estimated that more than 95% of white women had access to screening tests, compared with less than 5% of black women.
Women in their forties and early fifties show the highest levels of cervical cancer — and about 75% of women are diagnosed when the disease is advanced and often untreatable.
Currently women are supposed to be screened every decade from the age of 30. If this target is met, it has been calculated that cervical cancer would be reduced by two-thirds. But the screening programme is not comprehensive because of the shortage of resources and the competing health needs, such as HIV/Aids.