There are over 100 subtypes of the human papillomavirus (HPV), with more than 40 affecting the anogenital area.
Almost all cases of cervical cancer are caused by oncogenic HPV types. Types 16 and 18 are most commonly associated
with cervical cancer, detected in more than 70% of cases in Australia. Persistent infection with oncogenic HPV types
and subsequent cervical cell changes are associated with an increased risk of developing cervical cancer.
HPV infections of the genital epithelium are thought to be sexually transmitted through skin to skin or mucosa to
mucosa contact. Therefore, it is important to note that different types of sexual contact can lead to transmission,
including; genital skin-to-skin contact, vaginal sex, oral sex and anal sex.
While HPV infections are normally cleared naturally by the immune system, in some cases, an HPV infection that is not
cleared by the body can cause abnormal cervical cell changes. If left undetected and/or untreated, these changes can
develop into cervical cancer.
Less than 10% of new HPV infections will persist, and it is persistent infection and subsequent cervical cell
changes that are associated with an increased risk of developing cervical cancer. However, this usually takes a long
time, often up to 10 to 15 years. Invasive cervical cancer is rare and only develops in a small proportion of women
with high grade abnormalities.