Researchers have developed a new swab test that can identify origins of potentially dangerous cervical cell changes up to 4 years before they happen, according to a new study published by Barrett et al in Genome Medicine.
Scientists found that the new cervical screening method was more sensitive than other tests that are currently available, and could reliably predict advanced cell changes and cervical cancer in 55% of patients who had a human papillomavirus (HPV) infection but no visible cell changes under the microscope. These patients went on to develop advanced cell changes within the subsequent 4 years. The researchers hope that the swab test will enable earlier treatment for those who are predicted to develop the disease.
The new swab test’s development was part of a wider program aimed at engineering a single screening test to predict a patient’s risk of developing four types of cancers: cervical cancer, breast cancer, uterine cancer, and ovarian cancer.
Developing the New Swab Test
The swab test works by examining the DNA methylation of cervical cells, which can be affected by environmental and lifestyle factors—and some changes of which can increase the risk of certain diseases such as cancer.
To assess the reliability of the swab test, researchers retrieved and tested 1,254 cervical screening samples—stored at the Karolinska Center for Cervical Cancer Elimination in Sweden—from patients with cell changes ranging from early (cervical intraepithelial neoplasia [CIN] 1) to advanced (CIN 3); patients with HPV infection but no cervical cell changes; and patients without any cervical cell changes who went on to develop CIN 3 within 4 years.
The new method of analysis outperformed cytology and newer molecular tests that were in development for detecting those with CIN 3 and cancer.
“Vaccination against the causes of cervical cancer is now widely implemented and is leading to changes in the amount and types of the virus circulating in the community. In turn, our approaches to cervical screening must adapt so that programs continue to deliver benefit,” said swab test developer Martin Widschwendter, MD, Professor of Women’s Cancer and Head of the Department of Women’s Cancer at the Elizabeth Garrett Anderson Institute for Women’s Health at the University College London, Director of the European Translational Oncology Prevention and Screening Institute, and a consultant gynecologic oncology surgeon at the University College London Hospital.
“Importantly, our other work has shown how testing the same cervical sample can also deliver information on a [patient’s] risk of three other major cancers—breast, ovarian, and [uterine] cancers. Building new, holistic, risk-predictive screening programs around existing, effective cervical sample collection offers real potential for cancer prevention in the future,” he added.
When invited for cervical screenings, patients had samples taken from their cervixes using soft brushes. These samples were then tested for the presence of high-risk HPV, responsible for causing 99.8% of cervical cancers.
If high-risk HPV was present, the cells were examined under a microscope for the presence of changes that could have led to cancer if left untreated. Anyone who was found to have CIN was then referred to a further appointment, where the cervix was looked at closely by a specialist with a colposcope.
Conclusion
Anyone with early cell changes (CIN 1 or 2) may be screened more regularly until the cells have turned back to normal or treatment is needed. Those with advanced cell changes (CIN 3) may be treated using large loop excision of the transformation zone, where the abnormal cells are removed before they turn into a cancer.
“It’s so welcome to see screening tools and predictive tests becoming more effective. We want to prevent cancer—and we know with cervical cancer that we can intervene at an early stage,” said Athena Lamnisos, CEO of The Eve Appeal. “This new method is more specific and doesn’t lead to overtreatment, which is good news for cervical cancer prevention, and great news for everyone who needs to be screened.”
The research team is now moving on to the next stage of the study, where they will test the new technology on screening samples from patients who have been vaccinated against HPV and on self-sampled vaginal swabs.
Disclosure: The research in this study was funded by the European Union’s Horizon 2020, European Research Council programs, as well as genealogical cancer charity, The Eve Appeal, and the Swedish Foundation for Strategic Research. For full disclosures of the study authors, visit genomemedicine.biomedcentral.com.
