A study published online in the Journal of the National Cancer Institute suggests that women who test positive for HPV (Human Papillomavirus) aged thirty years or over should have a re-examination two years after their initial test as part of cervical cancer screening.
HPV infection is responsible for most causes of cervical cancer, despite the fact that most women with HPV have no cervical pathology and most HPV infections disappear in women under the age of 25 years. Screening for a specific strain of HPV is recommended for women aged thirty years or over since only some strains are linked to cervical cancer in addition to continual detectable infections.
So far, only few long-term studies have been conducted on these continual infections and their association with an increased risk of cervical cancer.
Hui-Chi Chen, PhD, of the Genomics Research Center of Academia Sinica in Taipei, Taiwan, and his team wanted to determine the link between persistent HPV infections and risk of cervical cancer in women aged 30 years or older. Their study included a group of 11,923 women between the ages of 30 to 65 over a 16-year period. The participants all had baseline examinations including HPV DNA testing and cytological tests with a repeat-test two years later. The investigators determined the incidence of cervical cancer from cancer registries and death registries. Of all participants, 6,666 women received a baseline examination plus a second screening, while 3,456 patients only received the first test.
The researchers established, that the 16-year risk of cervical cancer was 6.2% for women infected with any carcinogenic strains of the virus, whereas women who were persistently infected with carcinogenic HPVs over the 2-year testing period had a cervical cancer risk of 12.4% compared with a risk of only 0.14% in those who repeatedly tested HPV negative.
According to the researchers there is no benefit in repeating HPV testing more frequently than every two years in HPV-positive women, since it is the duration of the infection that represents the risk of cervical cancer and not one-time infections.
The authors explain: “Our findings suggest that, if upon testing an HPV infection is found, re-testing 2 years later would provide useful guidance as to the duration of infection and its risk.” They continue, concluding: “The accumulated evidence suggests that it is time to include HPV testing in cancer screening programs for the general population,” and add, that genotyping could improve HPV testing because certain carcinogenic HPV strains, HPV16 and HPV58, are linked to a higher risk of cervical cancer than others.
Kevin A. Ault, MD, of the Department of Gynecology and Obstetrics at the Emory University School of Medicine remarks in an accompanying editorial, that “persistent HPV infection is an intermediate step in the development of cervical cancer.” He acknowledges the magnitude of the study, including its long follow-up duration, large sample size, and linkage to the national cancer registry adding that the study reveals, that HPV-negative tested women have a greatly reduced risk of developing cervical disease.
Written by Petra Rattue