Stability analysis of an age-structured model of cervical cancer cells and HPV dynamics

Stability analysis of an autonomous epidemic model of an age-structured sub-populations of susceptible, infected, precancerous and cancer cells and unstructured sub-population of human papilloma virus (HPV) (SIPCV epidemic model) aims to gain an insight into the features of cervical cancer disease. The model considers the immune functional response of organism to the virus population growing by the HPV-density dependent death rate, while the death rates of infected, precancerous and cancerous cells do not depend on the HPV quantity because the immune system of organism does not respond to its own cells. Interaction between susceptible cells and HPV is described by the Lotka-Voltera incidence rate and leads to the growth of infected cells. Some of infected cells become precancerous cells, and the other apoptosis when viruses leave infected cells and are ready to infect new susceptible cells. Precancerous cells partially become cancer cells with the density-dependent saturated rate. Conditions of existence of the endemic equilibrium of system were obtained. It was proved that this equilibrium is always locally asymptotically stable whenever it exists. We obtained: (i) the conditions of cancer tumor localization (asymptotically stable dynamical regimes), (ii) outbreak of cancer cell population (that may correspond to metastasis), (iii) outbreak of dysplasia (precancerous cells) which induces the outbreak of cancer cells (that may correspond to metastasis). In cases (ii), (iii) the conditions of existence of endemic equilibrium do not hold. All cases are illustrated by numerical experiments.

Cervical cancer - causes and prevention of hpv infections in the opinions of young polish women: a cross-sectional survey

OBJECTIVE

Introduction: Cervical cancer is an important issue of gynecologic oncology. The awareness of this disease, the attitude towards HPV vaccination and cytological screening play an important role in decreasing morbidity and mortality due to cervical cancer. The aim: To assess the various aspects of knowledge regarding cervical cancer, risk factors for this disease, the role of HPV infection and the attitude to primary (vaccination) and secondary (cytological screening) prevention among young women.

PATIENTS AND METHODS

Materials and methods: The study was performed using CAWI method based on original questionnaire in electronic form. Online completing of the survey was voluntary and anonymous.

RESULTS

Results: The study was conducted in a group of 2058 women aged 19-33. In total 98.4% of respondents came across the term "cervical cancer", 84.1% knew that cervical cancer could be prevented and the following were identified as the main risk factors: cervical cancer in closest relatives (85.3%) and HPV infection (81.9%). Although according to 82.0% of women HPV infection can be prevented by vaccination, only 18.4% of respondents were vaccinated. The main reason for non-vaccination was lack of knowledge about the availability of the vaccine (41.2%) and high price (32.0%). Of the unvaccinated people, 63.5% declare their will to be vaccinated in the future. Concerning secondary prevention, 98.6% of the respondents admitted that they knew the term "cytological examination", 89.0% indicated that this examination detected the presence of pre-cancerous lesions, and according to 58.4% of respondents, this test should be performed after sexual initiation. Despite the fact that 80.5% of respondents confirmed the fact of beginning sexual activity (44.4% of them had more than 1 partner), 17.1% of the respondents admitted that they didn't go to gynecologist yet. Approximately 84% of respondents believe that the amount of information on cervical cancer prophylaxis and HPV infections currently providing is insufficient.

CONCLUSION

Conclusions: The basic terms regarding primary (vaccination) and secondary (prophylactic tests) prevention of cervical cancer have been widely known. However, the knowledge about specific risk factors, sexual behaviors contributing to HPV infection and, consequently, the ability to self-identify as belonging to higher risk group is insufficient. It is justified to conduct educational activities regarding the assessment of risks related to cervical cancer addressed to young women. Together with education, HPV vaccination and secondary prevention programs require financial support.