- Created on Wednesday, 08 May 2013 21:51
- Last Updated on Monday, 23 June 2014 13:50
HPV (Human Papilloma Virus) is the most frequent sexually transmitted infection (or STI). Approximately 550,000 Canadians, mostly women, are affected by HPV. HPV is so common that it is estimated that about 75% of sexually active women in contact with HPV during their lifetime (source: Healthy Canadians). Most HPV-infected women has no symptoms.
More than 100 types of HPV have been identified to date, including forty infecting the genital area. HPV types are divided into two categories: a "low risk" category which is not associated with the development of cancer and a "high risk" category which is associated with the development of cervical cancer of the uterus. About fifteen types of HPV are classified as "high risk."
PAP test in solution (ThinPrep™)
Analysis of PAP test in solution by the ThinPrep™ technique is an exclusivity of private laboratories in Quebec. Several worldwide studies have shown that the PAP test in solution is more accurate than the conventional PAP smear and helps to detect precancerous cells (Limaye et al., 2004).
The PAP test in solution is a cervical smear. The doctor gently scrapes cells from the cervix, cells are then deposited into a vial of liquid (rather than spread on a slide as for a conventional PAP smear) and then the vial is sent to the laboratory for microscopic examination. This method also allows the physician to preserve the entire sample and thus makes the ThinPrep™ slide easier to read in the laboratory. The PAP in solution detects the presence of abnormal cells but does not identify the type of HPV present.
HPV DNA testing
When a PAP test in solution is considered as abnormal, HPV DNA testing is highly recommended. Indeed, this screening will allow to know what type(s) of HPV is (are) present in the cells of the cervix. Especially, the detection of HPV DNA indicate whether the patient is a carrier of a "high risk" HPV of cervix cancer. Screening for HPV DNA requires no new collection since it is performed on the same sample as the PAP test in solution. Curalab Genetics provides a test for HPV DNA approved by the FDA (Food and Drug Administration) in the United States and Health Canada. This test consists in the genetic analysis of HPV DNA that will help determine whether a woman is a carrier of one or more of 13 types of a "high risk" HPV of cervix cancer.
Achieving a PAP test in solution and a HPV DNA testing (if needed) is an excellent way to detect cancer of the cervix.
About cervix cancer
- On average, one woman dies every day in Canada of cervical cancer of the uterus.
- You can prevent cervical cancer by screening (PAP test in solution and/or HPV DNA testing), which can detect abnormal cells and precancerous changes before they become cancer.
- Cervix cancer is caused by certain types of "high risk" HPV.
- There are two vaccines against HPV to protect against two types of high-risk HPV, which are responsible for approximately 70% of cervical cancer of the uterus. Even if a person received a vaccine, she may still be infected with one of the other types of high-risk HPV not covered by the vaccine. It is important for girls and women to undergo regular PAP tests.
Limaye A, Connor AJ, Huang X, Luff R. Comparative analysis of conventional papanicolaou tests and a fluid-based thin-layer method. Arch Pathol Lab Med. 2003;127:200-4.