?As the fourth most common cancer in women globally, cervical cancer remains a major health challenge. Over 90% of deaths occur in low- and middle-income countries (LMICs) with sub-Saharan Africa being one of the hardest-hit regions. Cervical cancer, which develops because of a long-term infection with the human papillomavirus (HPV), is the number one cause of cancer deaths in women in South Africa, despite advances in early detection and prevention.
“Although there has been a shift from cell-based cervical cancer screening to HPV DNA screening, the latter alone often is not specific enough to deliver clinically useful results to identify women who are at risk of developing cervical disease," says Dr Robyn Adams who recently obtained her doctorate in obstetrics and gynaecology at Stellenbosch 中国体育彩票. The title of her PhD study was “Exploring options for the secondary prevention of cervical cancer in South Africa".
Adams investigated using a chemical process called DNA methylation as a molecular test to prioritise care in HPV screening programmes, especially for women who are living with HIV and test positive for certain high-risk HPV types but do not receive direct referral for treatment. Women living with HIV are at a greater risk of persistent high-risk HPV infections and cervical cancer because of weakened immune systems.
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DNA methylation offers a potential solution to enhance the specificity of HPV screening, according to Adams. She explains: “The DNA methylation marker test works by detecting specific changes in the DNA of cervical cells. These changes, known as methylation, occur when methyl groups or 'tags' are added to certain parts of the DNA. These 'tags', which act like switches, can affect how genes are activated to read the instructions in the DNA to make proteins that help the cells do their work.
“When HPV infection causes changes in the cervical cells, it can lead to abnormal DNA methylation patterns. The test focuses on two key biological indicators which have been shown to be associated with the presence and severity of cervical disease, including cervical cancer."
Adams says this test is unique because unlike traditional methods like cell checks, which look for abnormal cells, it targets changes in the DNA that happen earlier in the disease allowing it to detect clinically significant HPV-associated cervical abnormalities that are more likely to progress to cancer.
“By detecting these early molecular changes, DNA methylation testing provides a more accurate way to identify women who are at greater risk of developing cervical cancer. This is particularly important in environments where delayed access to treatment and follow-up care is a challenge.
“When used together with HPV testing, it offers a more accurate way to determine whether an HPV infection is likely to cause significant disease or if it is just a temporary infection that does not require immediate intervention. She adds that this test can be also performed on the same sample used for HPV testing, whether it is collected by a healthcare worker or via self-sampling."
Adams does point out, however, that although the test correctly identified women with cervical problems, it produced a high number of invalid results, failing to provide clear answers in some cases.
“Because the invalid results suggest potential reliability issues, additional research with a larger pool of participants is needed to refine it and confirm its effectiveness. While the test shows promise, further work is required to determine its suitability for routine cervical cancer screening. Improving affordability will also be critical, particularly for implementation in South Africa and other LMICs."
As research on this topic continues, Adams recommends that we align our national cervical cancer prevention policy with World Health Organization (WHO) guidelines, which prioritise HPV DNA testing as the gold standard for primary screening. In South Africa, many doctors still recommend Pap smears but there is a rapid adoption of HPV testing as a better, more accurate method for cancer screening.
“Aligning the national policy with WHO guidelines would ensure consistent implementation across all provinces and create a unified and equitable cervical cancer screening programme that addresses the country's diverse healthcare challenges.
“We can achieve this by accelerating the nationwide transition to HPV DNA testing; incorporating self-sampling options to address barriers to access; strengthening data collection and monitoring systems to track progress, identify gaps, and ensure programme sustainability; regularly updating the national policy to reflect new scientific evidence; and ensuring differentiated screening approaches for women living with HIV, including shorter intervals, earlier screening starting at age 25, and tailored strategies that can prioritise treatment for these women based on the severity of their condition and improve early detection."
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