1928 Greek-born American scientist George Nicolas Papanicolaou described the diagnosis of genital cancer by examining cells. Researchers from various countries have been working to improve the diagnosis of cancer. The Austrian gynecologist Schouenstein described superficial cancer, otherwise known as carcinoma in situ, i.e. cancer has not grown into the deeper layers of tissue.Testings have become clear that invisible superficial cancer can be found and diagnosed in vaginal or cervical smears. 1940 The results of a series of hugely successful projects were presented in 2006, proving that vaginal and cervical smears can be found in ‘secret cancer’, which can lead to astonishing treatment results. In honor of Papanicolaou, the smear came to be called the “Pap smear.”
Pap smear, as a procedure to eliminate a fatal disease in the identification and treatment of precancerous disease, has been widely adopted as a vaginal and cervical screening in the United States and has become a common and well-known term. The study of the same name has spread to other countries. Until Pap smear was introduced into clinical practice, mortality from cervical cancer in the United States was one of the dominant causes. In fact, no other test in the world has been so successful and effective in eradicating cancer. Unfortunately, in Lithuania, these studies are not carried out widely enough, and in all cases not in the way they should be done.
Pap smear, when performed qualitatively, makes it possible to detect invisible changes in the cervix and which can still help in the presence of the patient. One of the major infections influencing the development of cervical cancer is the oncogenic types of human papilloma virus / HPV / 8 (16.18 less frequently 31.32, 33.45, 56.58). Other genital infections that cause reactive changes in cells without treatment, leading to deeper changes called dysplasia and later superficial cancer, are also known as pre-cancerous changes. Within the limits of the above-mentioned changes, if diagnosed in time, the patient can be helped in 100% of cases. The many years of experience of U.S. researchers indicate that the peak of cervical precancerous diseases is among young women. Cervical cancer is more common in the group of older women.
What do you need to do to prevent cervical cancer?
Recommendations from the world’s scientists to this day – all women over the age of 18 who have sex should have a Pap smear every year. High-risk patients, such as those who change partners frequently, have an early sexual life, give birth many times, and use oral contraceptives for five years or more, need to be checked more often. An annual Pap smear test should also be performed on women 65 years of age. Unfortunately, in Lithuania, the Pap test is not included in the list of routine tests during a gynecological examination for various reasons. However, health is everyone’s concern, it is your own concern and patients themselves should insist that a gynecological examination, even once a year, be performed with a quality Pap smear.
Cervical cancer does not develop suddenly, it takes 6 to 10 years for the cell to shrink and grow into deeper tissues. When a patient is diagnosed with cervical cancer, it is a late diagnosis.
THE ROLE OF HUMAN ADDITIONAL VIRUS INFECTION IN THE DEVELOPMENT OF THROUGH CANCER
It has been more than 20 years since the human papillomavirus (HPV) was discovered in cervical carcinomas and the first genital HPV type was identified. Today, there is no doubt that the papillomavirus plays a major role in the development of cervical carcinomas. The discovery of new genital HPV types and the development of new specifically sensitive detection methods have shown that as many as 100% of squamous cervical carcinomas and more than 70% of adenocarcinomas are associated with HPV DNA findings in them. More than 150 types of human papillomavirus are currently known. Some of them infect the mucous membranes of the genital tract. These types differ from each other in their transforming properties and are divided into risk groups accordingly. Low-risk HPV (types 6; 11; 42; 43; 44) is most commonly associated with exophytic Candilomata acuminata, flat warts, and mild dysplasias (6 and 11 are rarely found in vertebral carcinomas). Meanwhile, high-risk types (16; 18; 31; 33; 35; 39; 45; 50; 53; 55; 56; 58; 59; 64; 68) are identified in samples of carcinomas and dysplasias of varying degrees. Several types of HPV in this group (31; 33; 35; 51; 52) are referred to by some authors as intermediate-risk group viruses because they are more common in moderate to severe dysplasias than in carcinomas. Of all genital HPV types, HPV-16 and 18 are most commonly found in squamous cell carcinomas of the cervix. More than 50% of these tumors have HPV-16. In contrast, more than 50% of all adenocarcinomas are detected in HPV-18. The prevalence of other virus types varies depending on the geographical region.
Most epidemiological studies have shown that the risk of developing cervical cancer is strongly associated with the presence and persistence of high-risk HPV. Additional factors called cervical risk factors (chemical, hormonal contraceptives, other viral or bacterial infections) do not appear to be significant, except for smoking, for which data vary widely and are cited as a strong factor in the development of various high-grade dysplasias.
HPV infection enters the cells of the cervix through the genital tract and can then be activated after microabrasion or other interventions that damage the cervix.
Cellular changes in cervical cancer.
About 15% of women have abnormalities in the maturation of various squamous epithelial cells seen in the PAP smear. The terminology of the lesions, describing the progressive stages of cytological changes in the PAP smear, is described according to the Bethesda system in an attempt to avoid numerous term discrepancies. The minimal cytological changes are called ASCUS (Atypical Squamous Epithelium of Uncertain Significance). There is clear evidence that the cause of most ASCUS is HPV infection in squamous epithelial cells. In women with ASCUS / HPV, lesions are more likely to progress to LGSIL (low-grade squamous intraepithelial lesion). The average time from ASCUS to LGSIL development is about 4 years. In patients, LGSIL often returns to normal without any treatment. Only about 20% of women develop LGSIL into Highly Squamous Intraepithelial Lesion (HGSIL). This progression also lasts for about 4 years. HGSIL is also called marked squamous epithelial lesions or carcinoma in situ. HGSIL is usually an irreversible change. Some studies have shown that a small proportion of untreated patients with HGSIL spontaneously return to lower-grade lesions. However, in most cases, HGSIL is not left without treatment. Most patients not treated with HGSIL progress to microvasive and subsequently to more advanced invasive cancer, which takes more than 9 years to develop.
| NORMA | ASCUS / HPV | LGSIL | HGSIL | CANCER | ||||
| » | » | » | » | |||||
| « | « | « | ||||||
| 15% | 90% | 20% | 30% |
HPV detection methods
When material from the cervix is sent for cytological or histological examination, GPs should also require HPV testing. Only highly sensitive and specific HPV detection methods should be used in clinical practice to avoid false-positive and false-negative results. Currently, there are only two systems that meet these requirements: PCR and Hybrid Capture (HC) assays. Other HPV testing methods are usually used for research purposes only (RNA in situ hybridization) or are too complex for routine testing (Southern-glot hybridization). In situ hybridization using specific RNA or DNA HPV probes can be used in paraffin blocks to determine the exact location of HPV infection or for the expression of HPV oncogenes.
