Dr Robyn Adams researches new methods to detect cervical cancer.
A SOUTH African scientist is investigating a new medical test which it is hoped will result in identifying women at greater risk of cervical cancer.
Cervical cancer, the fourth most-common cancer in women globally, is a major health challenge with over 90% of related deaths in low- and middle-income countries (LMICs) and sub-Saharan Africa among the hardest-hit regions. In South Africa, it is the leading cause of cancer deaths in women despite advances in early detection and prevention. Cervical cancer develops because of a long-term infection with the human papillomavirus (HPV).
Dr Robyn Adams, who recently obtained her doctorate in obstetrics and gynaecology at Stellenbosch University, said there had been a shift from cell-based cervical cancer screening to HPV DNA screening, but alone it was often not specific enough to identify women at risk of developing cervical disease.
Adams, whose PhD study was titled “Exploring options for the secondary prevention of cervical cancer in South Africa”, investigated using a chemical process called DNA methylation to prioritise care in HPV screening programmes, especially for women living with HIV and test positive for certain high-risk HPV types but do not receive direct referral for treatment. HIV-positive women are at higher risk of persistent high-risk HPV infections and cervical cancer because of weakened immune systems.
“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,” said Adams.
The 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.
The test provides a more accurate way to identify women at greater risk of developing cervical cancer, which is 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."
However, although the test correctly identified women with cervical problems, it also produced a high number of invalid results, failing to provide clear answers in some cases, necessitating additional research with more participants to refine it and confirm its effectiveness.
Adams recommended that South Africa's national cervical cancer prevention policy be aligned with World Health Organization (WHO) guidelines, which prioritise HPV DNA testing. In South Africa, many doctors still recommend Pap smears while there is a rapid adoption of HPV testing as a more accurate method for cancer screening.
The Independent on Saturday