Pap test and HPV test

In the previous video we started learning about the human papilloma virus, also known as HPV. We have seen how it is responsible for benign genital warts and warts, but also for lesions that can evolve into various cancers. In particular, we have highlighted how genital papilloma virus infection represents the main cause of cervical cancer, or cervical cancer, if you prefer. HPV infections are extremely widespread and contagion occurs mainly through sexual activity, but it is also possible through intimate skin-to-skin contact. In cases where the immune system cannot overcome the infection, this disease slowly progresses to the formation of pre-cancerous lesions, called dysplasias. Fortunately, if detected in time, these lesions can be effectively treated and resolved, before they evolve. further towards the tumor. The most effective weapons against the papilloma virus are therefore two: on the one hand we have the new one, which is the preventive vaccination, on the other the classic one, which allows to identify in time the precancerous alterations through Pap-test, which we will talk about today.

In the previous video, we also saw that there are more than 100 different types of HPV. Of all these viruses, about 15 genotypes are considered "high risk" oncogenes, that is, strongly associated with cervical cancer. To be precise, the most dangerous ones are in particular the HPV 16 and HPV 18 viruses, which are alone responsible for about 70% of cervical cancer cases. It is important to remember that it takes many years for HPV-induced lesions to develop into cancer. In addition, both infections and pretumor lesions are often asymptomatic, so the woman does not notice their presence. For all these reasons it is important that the woman plays in advance, so to speak, by regularly carrying out specific screening tests capable of identifying any lesions. These include the Pap test or Papanikolaou test, named after the Greek-American doctor who invented it.

By resorting to screening tests, not only is it possible to identify tissue abnormalities early, but also the possibility of treating and resolving them adequately before they degenerate. The Pap smear is the classic screening test for cervical cancer. Its introduction has significantly contributed to the reduction of mortality associated with this type of cancer, which is now very low in industrialized countries but still very high in developing countries, where cervical cancer is the most frequent cancer among women. For this reason, the Pap test should be performed regularly by all women (even asymptomatic), starting from the age of 25 and repeated every three years. Unless otherwise indicated by a doctor, undergo a Pap test once a year is today considered not only useless, but even harmful since it increases the risk of useless treatments. The ideal frequency with which to repeat the test is therefore once every three years.

The execution of the Pap test is quite simple, not painful or traumatic. The doctor inserts a small retractor, called a speculum, into the vagina to facilitate the removal. Then, with a special spatula and a swab, it gently collects some cells from the most superficial layers of the cervix and cervical canal. The collected cells are then smeared on a glass slide, sprinkled with reagent and sent to the laboratory. Microscopic analysis of the sample allows to identify any cells with pre-tumor or tumor characteristics and, based on their degree of atypicality, to estimate the level of tissue damage. Before undergoing the examination, it is necessary to suspend any treatments with vaginal ovules or candlesticks at least in the previous two days. Likewise, it is necessary to avoid internal vaginal douching, bathing in the tub and sexual intercourse in the previous 24 hours. The Pap test also cannot be performed during the menstrual period. When the Pap test does not show lesions, it is said that the test has a negative result and the woman is asked to repeat the test after three years. When, on the other hand, the Pap test is positive it means that the cytological examination has found the presence of abnormal cells; in these cases, in-depth examinations are required. In particular, first of all, the woman is invited to undergo a colposcopy. The gynecologist uses a special instrument, called a colposcope, which allows to illuminate the cervix and to see it enlarged. In this way, it is able to confirm the presence of lesions, evaluate their extent and perform a biopsy. The biopsy consists of a small sample of tissue from the cervix, from submit to the histological examination for confirmation, in other words, it definitively confirms the exact characteristics of the suspected lesions.

In addition to the Pap test, another screening test is now available, called the HPV test, which allows us to identify the presence of papilloma virus DNA in cervical cells. Compared to the Pap test, therefore, it is discovered if the woman has contracted a potentially oncogenic virus, even before any lesions develop. In other words, this test can identify women with a predisposition to cervical cancer. The HPV test is performed in a similar way to that of the Pap test. It consists, in fact, in the removal of a small amount of cells from the cervix. The material taken, however, will not be read under a microscope, but subjected to a laboratory test for the detection of the virus. The HPV test was introduced as a completion test to the Pap test, especially useful for women with slightly abnormal results. Today, however, we know that from the age of 35 it can be performed at the instead of the Pap test, as primary screening test. All this thanks to the undoubted advantages in terms of sensitivity. In fact, the HPV test is able to recognize even those cases that escape the Pap test and therefore has a greater ability to prevention of cervical cancer.A negative HPV test means that no papilloma virus gene material has been identified in the cells of the uterine cervix, so the woman is not at risk and can be excluded from further tests. Conversely, a positive result confirms the presence of viral DNA. However, a positive HPV test does not have to cause anxiety, because it does not necessarily mean that a tumor is present or that it will develop in the future. This is because the HPV test is able to identify even infections that may spontaneously regress. For this reason, the examination is recommended for women over 30-35 years old, since infections destined to regress spontaneously are common below this age. Furthermore, unlike the Papanikolaou test, in case of negative HPV test is repeated not every three, but every 5 years.