HPV Screening and Cervix Cancer

Question 1. What is HPV? HPV stands for Human Papilloma virus which comprises of over 150 closely related virus types indicated by numerical numbers e.g., HPV type 16, 18, and 45 that cause cervix cancer. HPV types range from benign forms such as those causing simple/common skin wart to those causing cancer as type 16 & 18.

 Question 2. How does HPV cause cervix cancer? Certain types of HPV cause cancer when they remain in the body for many years.  They cause mutation or induce change in genes (DNA) of normal cells so that they behave, and function abnormally which is how cancer cells behave. HPV types that cause cancers are known collectively as high-risk HPV types. There are 14 high-risk HPV types and include 16,18,31,33,35, 39, 45,51,52, 56,58, 59,66 and 68.  Only types 16 and 18 are responsible for majority of HPV-related cancers such as cervix cancer and cancer of vulva, labia, mouth, throat, voice box and tongue. 

Question 3. How is it spread? HPV is easily spread through direct skin-to-skin contact and sexual activity. Luckily, many of us are able to get rid of them even if they are high-risk types and have no concern for transmission. However, few are not so lucky for various reasons, and the virus can cause cancer if the person harbors the virus for longer period say over 10-20 years.

 Question 4. What is the basis of HPV Screen? HPV type 16 & 18 causes majority (85-95%) of cervix cancer. Traditionally pap smear is done to look for signs of cancer in the cervix. Cancer develops slowly over many years after HPV infection has occurred. Therefore, by testing HPV infection, we can pick up persons at risk of cancer before any evidence of pre-cancer or cancer signs. In this way, testing for signs of HPV infection is screening test for possible cervix cancer instead of doing pap smear, which is time consuming, often seen as embarrassing procedure and not accepted easily by patients. If positive HPV patients is identified, they will have pap smear and arranged for regular follow-up to pick up early cancer. By having regular HPV test checks, cancer can be picked up early and treated before it spreads and kills the patient. 

Question 5. Can HPV affect man? Yes. HPV causes many types of lesions on skin including prepuce of penis, and oropharyngeal mucosa surfaces. It is linked to oral cancers, cancers of upper airway and voice box. Hence, males can get HPV-related diseases including cancers. 

Question 6. How is HPV test done? HPV is tested on swab taken from cervix or skin lesions for testing. PCR Test for HPV DNA is recommended test for HPV screen. It has over 95% sensitivity and specificity. Other tests, available including antigen tests using rapid card test kits. Rapid card test is less well established or popular, and information on sensitivity and specificity aren't unified. 

Question 7. I have positive HPV test. Do I have cancer? Positive HPV tests only means that you are harboring the virus. All positive females will need pap smear test done to see if she has developed any cancer or pre-cancerous lesions in the cervix. If no lesion is found, she only needs closer follow-up to retest HPV or perform pap smear every year as being positive for longer period can lead to cancer in the long term. The good news is that for majority of people, HPV will be cleared, and even positive test can turn negative during follow-up. It is established that majority of females below the age of 30 show positive HPV test and later show negative on follow-up testing. Therefore, HPV testing should only commence after 40 years to prevent unnecessary anxiety and reduce cost and inconvenience of follow-up testing of people younger than 40 who would naturally turn negative with time. 

Question 8. I have negative test. Am I free of cancer? Negative HPV test is good news as it implies that you are not at higher risk of cervix cancer compared with someone who is positive. However, a small per cent (5-10%) of cervix cancer is not related to HPV infection. Therefore, although you are at low risk, if you have family history or have symptoms, you should still have regular follow-up & pap smear done to exclude HPV negative cervix cancers. 

Question 9. Is there any false positive or false negative result? Yes. There are many reasons you could have false positive and false negative results. It is recommended that you repeat the test preferable in another lab or using another kit if you are in doubt. However, this is less common with the availability of good test kits and equipment nowadays. 

Question 10. How often can I have HPV Test? It is recommended that women should have HPV testing done after 40 years every two years or yearly if, they are already positive for HPV type 16, 18 and 45. 

Question 11. Which is better? Pap smear or HPV screen? Overall, HPV testing is more convenient, less costly and acceptable by patients compared to pap smear. Furthermore, HPV testing will pick up many cases of at-risk patients' and patients with cervix cancer than pap smear. In other words, HPVDNA testing is highly specific and sensitive and when negative it means in many cases, you don't have cancer and are not at risk of future cancer. However, pap smear is still important procedure to perform when a patient is positive to see if she has cancer or pre-cancerous lesions. pap smear can also pick up non-HPV related cancer or genital lesions that cannot be diagnosed by HPV testing alone such as cervicitis, candida infection or other sexually transmitted diseases. 

Question 12. Which is better? Genetic or antigen test for HPV? At this stage, genetic testing is better and recommended although antigen testing is cheaper and convenient to do as it utilizes rapid card test technique compared to genetic HPV testing that uses expensive PCR equipment not easily accessible to communities of developing world and rural areas. 

Question 13. What is the cost of HPV test? HPV testing isn't widely available in PNG. Recently, Mt Hagen Base hospital through NGO funding has started the HPV DNA testing program for women living in the highlands.  Our clinic is introducing HPV antigen testing soon and will cost less than K100. You will be given cotton swab to collect sample at home and bringing it to the clinic for testing. Results are available immediately. If positive, we will refer you for a pap smear or HPV DNA testing. If negative and you have no other complaints like vaginal discharge, abdominal pain, pain on sex, etc., we recommend repeat HPV testing every two years. 

Question 14. How long will my result be available? Results of HPV DNA testing is available same day in most clinics. Results of Rapid test kit test is usually available instantly.