HPV strains and risk of cervical cancer
There are approximately 40 strains of HPV that infect the genital mucosa. These genital HPV strains are classified into low or high risk by their susceptibility to cause cervical cancer [1, 3]. There are 14 high risk strains of HPV that are associated with cervical cancer. Of the high risk types, the most notable strains are HPV 16 and HPV 18. Together, HPV 16 and HPV 18 account for 70% of all cervical cancers [1, 3, 5, 8].
The HPV DNA test performed at MDS specifically differentiates the presence of HPV 16 and 18. Furthermore, the test detects the presence of the additional 12 high risk strains which include HPV 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68.
HPV screening guidelines
The South African guidelines for HPV screening recommend that all women should initiate HPV screening from the earliest age of 25 years old or at the time of a positive diagnosis of HIV. In the case of a negative result, HPV screening should occur at 5 yearly intervals or 3 yearly intervals for HIV positive cases if undergoing an HPV DNA test .
The gold standard for cervical cancer identification has been the Pap test. However, as the role that HPV plays in contributing to cervical cancer has been better understood, screening for the presence of the HPV virus has started to rival that of the Pap test. Recent studies have shown that screening for HPV is more accurate in determining cervical cancer risk than that of the Pap test. Additionally, women with a negative HPV test had half the risk of developing cancer over three years as women who had a negative Pap test .
This principal can be further explained by understanding the difference between the HPV test and the Pap test and what the end result aims to identify. For both the HPV test and the Pap test, a health care provider will scrape cells from the surface of the cervix. During the Pap test, the cells collected are analyzed under a microscope for abnormalities . Changes to the morphology of the cells are known as cervical intraepithelial neoplasia (CIN) and can be classified as CIN 1 (low grade lesion) to CIN 3 (high grade lesion) which indicates the stages of infection and persistence that lead to the development cervical cancer [5, 12].
On the other, the HPV test detects the presence of HPV DNA in cells. This allows for earlier detection at a much higher sensitivity before any changes to cervical cells can be visualized morphologically. As a result, health care practitioners are enabled to provide earlier treatment options and less invasive management protocols to their patients, ultimately preventing the progression of the infection to a cancerous state .
An HPV DNA negative result indicates that you do not have an HPV strain that is linked to the development of cervical cancer. As a result, the overall risk for cervical cancer is low and no additional testing is required for 5 years (unless factors such as changes in sexual partners occur within this time frame or one is infected with HIV etc) .
An HPV DNA positive result indicates that you do have an HPV strain that is linked to the development of cervical cancer. Further testing is required to determine the level of advancement of the infection. Result management guidelines will differ according to the resources available to the health practitioner. However, the South African HPV advisory board recommends the following procedures :
- Women who test positive for HPV 16 and 18 should undergo a colposcopy and/or biopsy. A colposcopy is an examination procedure that magnifies the cervix so physicians can take a better look at abnormal cells and take biopsies if needed.
- Women who test positive for other high risk strains of HPV should have a Pap test as a follow-up to determine the morphological state of their cells and identify any precancerous lesions.
Ordering an HPV test
Clients can email/phone MDS ([email protected] or 031 2677000) to arrange an appointment with the nurse at MDS so that their sample can be taken and tested.
Clients can order an easy-to use, self collection kit from MDS where the sample can be taken in the privacy and comfort of their own home, and sent to MDS. To order a self collection HPV DNA test kit, please complete the HPV DNA Order Form and send it back to MDS with proof of payment.
Clients can also email / phone us to request a request form and take this to their GP/Gynaecologist to request that an LBC (liquid based cytology) sample be taken and be delivered/couriered to MDS.
MDS uses the latest technology to test the sample and provides a result to the Client / Doctor within 24 hrs. The result will inform the client of her HPV Status. All HPV High Risk Positive results will include a recommendation by MDS that the client consult a Doctor for further testing and / or treatment.
MDS offers various women’s health panels e.g. for Candida that can also be requested. Please refer to the Women’s Health request form for further details.
Should you have any further questions or wish to request an HPV test, please do not hesitate to contact us.