Visual inspection after application of acetic acid (VIA) Ė VIA to triage women positive on the HPV test
The HPV detection test is much more sensitive than cytology or VIA. Because of the high sensitivity, HPV-negative women can be screened at longer intervals (e.g. 10 years vs 3Ė5 yearly screening for VIA or cytology). The HPV test is not subjective, and a technician can be trained to perform the test with high competency. The test results can be obtained within an hour. Women can collect vaginal samples themselves (self-collection) for the test. Because of all these advantages, high-income countries are gradually switching their existing cytology-based screening programmes to screening based on HPV detection. The test is expected to become more affordable in the future, and then many low- and middle-income countries will also be able to adopt the test.
However, an important limitation of the HPV test is its low specificity, which means that a high proportion of women with a positive HPV test will not have cervical precancer or cancer. To reduce referral of all HPV-positive women for colposcopy and/or treatment, a triage test is needed to identify those women who are at greatest risk of having the disease. For example, cytology is the most widely recommended triage test for HPV-positive women in high-resource countries.
In settings where high-quality cytology is not available, HPV-positive women may be triaged with VIA. HPV-positive but VIA-negative (triage-negative) women are advised to repeat the HPV test after 1 year. HPV-positive and VIA-positive (triage-positive) women are immediately assessed for ablative treatment and if eligible, are treated with thermal ablation or cryotherapy. HPV and VIA positive women ineligible for ablative treatment or suspected to have invasive cancer should be appropriately referred and managed.
Many of the HPV detection technologies also provide information on the presence or absence of HPV types 16 and 18 (the two most oncogenic types). An effective management strategy can be to refer to colposcopy or treat all women positive for HPV 16/18 and use VIA only to triage women positive for HPV types other than HPV 16/18.