Use of HPV testing in cervical cancer screening services in Mexico, 2008-2018: a nationwide database study

Factors associated with receiving results and attending colposcopy in patients with positive HPV screens in Mexico City

We identified patient and healthcare system factors related to receipt of screening results and attendance to colposcopy among patients with positive screening results in a cervical cancer screening program in Mexico City, Mexico. We analyzed data from 1,351 patients with high-risk human papillomavirus (HPV)-positive results from two screening demonstration studies conducted between 2017 and 2018. Factors associated with receipt of screening results and with adherence to a colposcopy appointment were identified using multivariable logistic regression. Participants had a median age of 40 years (IQR = 32-48), 60% had less than high school education, and 74% had a previous Pap screening in the last 5 years. Fifty-five percent of participants retrieved their screening results at the healthcare facility (HCF) without any reminder. Providing an email address for contact information, attending a HCF with family medicine, and receiving care from experienced nurses were associated with greater adherence to obtaining screening test results. Fifty-seven percent of participants attended their first scheduled colposcopy appointment. Providing a phone number improved adherence to colposcopy, whereas longer travel times between the HCF and the colposcopy clinic was associated with a decrease in colposcopy adherence. Having a Pap test in the last 5 years was positively associated with better compliance with both outcomes. Securing contact information may help to overcome barriers to future follow-up. Additional research is necessary on strategies for obtaining screening test results and scheduling appointments, which may help address barriers to access, such as limited staff availability, distance from the clinic, and travel costs.

The health system and access to treatment in patients with cervical cancer in Mexico

Cervical cancer (CC) is tightly related to a low Human Development Index. Mexico is an upper-middle-income country with 126 million inhabitants, and its public health system aims to provide universal health coverage. Currently, employment-based social insurance covers approximately 60% of the population, and the scope of the remaining 40% is on course via the "IMSS-Bienestar" Institute. However, the annual government spending on health remains at 3% of the Gross Domestic Product, which is well below the 6% recommended by the Organization for Economic Cooperation and Development. CC is the second in incidence and mortality among women. Regarding primary prevention with the Human Papilloma Virus-vaccine, the current coverage for girls aged 9 to 14 years is only around 7%. Among secondary prevention with screening, the program is yet to cover the total number of women at risk; nevertheless, the age-standardized CC mortality rate has decreased from 12 per 100,000 women in 1979 to 5.7 per 100,000 women in 2020 due in part to increased screening coverage. Still, around two-thirds of patients present with locally advanced disease at diagnosis. Data from our country demonstrate that even socially disadvantaged CC patients achieve "standard" survival outcomes if treatment is granted. Nevertheless, there is a shortage in almost every aspect regarding CC treatment, including oncologists, chemotherapy units, medical physicists, radiation technicians, and both teletherapy and brachytherapy facilities. In conclusion, advances in the public health system in Mexico are urgently required to achieve CC control and reduce the mortality from this neoplasia that mainly targets socially disadvantaged women.

Comparative performance of the human papillomavirus test and cytology for primary screening for high-grade cervical intraepithelial neoplasia at the population level

The World Health Organization recommends high-risk human papillomavirus (hrHPV)-based screening for women 39 to 49 years, based on the greater accuracy of hrHPV-based screening for cervical cancer detection. Many cervical cancer screening programs have incorporated hrHPV testing and multiple early cervical cancer detection strategies have been evaluated, mostly under controlled conditions. However, there are few evaluations of combined hrHPV and cytology strategies post-implementation at the population level. Our study sought to estimate the relative yield of hrHPV testing compared to cervical cytology, as a primary screening test for cervical intraepithelial neoplasia grade 2+ (CIN2+), used at the population level. We analyzed screening data from Mexico's public cervical cancer prevention program from 2010 to 2015 in women 35 to 64 years. The study population consisted of two cohorts: one from a total of 2 881 962 cytology-based screening tests and another from a total of 2 004 497 hrHPV-based screening tests, which are concurrent in time. We performed a relative yield analysis using Poisson regression models to compare the effectiveness of hrHPV testing for CIN2+ with cervical cytology. A total of 4 886 459 records were analyzed, including 23 999 biopsies; 0.12% (n = 6166) had a CIN2+ histologic diagnosis. hrHPV testing with cytological triage detects twice as many CIN2+ cases as screening using cytology alone.

Human Papillomavirus Coinfection in the Cervical Intraepithelial Lesions and Cancer of Mexican Patients

According to their oncogenic properties, Human Papillomaviruses (HPVs) are classified into two types: Low-Risk (LR-HPVs) and High-Risk Human Papillomaviruses (HR-HPVs). The immune system naturally controls the majority of HPV infections; however, when the HR-HPV infection is persistent, the risk of developing cervical cancer increases. Previous studies indicate that multiple-infection or coinfection with HR-HPV occurs frequently and can potentiate the development of cervical lesions. This study aimed to establish the HPV coinfection rate in squamous intraepithelial lesions from Mexican patients. For HPV detection, we performed PCR on 55 cervical lesions diagnosed by colposcopy. We detected the presence of HPV infection in 87.27% (48/55) of the lesions; interestingly, HPV coinfection was observed in 70.83% (34/48) of these samples. We also evaluated HPV infection in adjacent areas without morphological changes from 25 samples. The results showed that 80% (20/25) of these were HPV-positive and, curiously, all presented HPV-16 infection. In conclusion, our results revealed a high prevalence of HPV coinfection in cervical lesions in Mexican patients, and these results contribute to future research focused on the role that HPV coinfection plays in the development of cervical cancer.

Multiple HPV Infections and Viral Load Association in Persistent Cervical Lesions in Mexican Women

Persistent high-risk human papillomavirus (HR-HPV) infections play a major role in the development of invasive cervical cancer (CC), and screening for such infections is in many countries the primary method of detecting and preventing CC. HPV typing can be used for triage and risk stratification of women with atypical squamous cells of undetermined significance (ASC-US)/low-grade cervical lesions (LSIL), though the current clinical practice in Mexico is to diagnose CC or its preceding conditions mainly via histology and HR-HPV detection. Additional information regarding these HPV infections, such as viral load and co-infecting agents, might also be useful for diagnosing, predicting, and evaluating the possible consequences of the infection and of its prevention by vaccination. The goal of this follow-up hospital case study was to determine if HPV types, multiple HPV infections, and viral loads were associated with infection persistence and the cervical lesion grade. A total of 294 cervical cytology samples drawn from patients with gynecological alterations were used in this study. HPV types were identified by real-time PCR DNA analysis. A subset of HPV-positive patients was reevaluated to identify persistent infections. We identified HPV types 16, 18, and 39 as the most prevalent. One hundred five of the patients (59%) were infected with more than one type of HPV. The types of HPV associated with multiple HPV infections were 16, 18, and 39. In the follow-up samples, 38% of patients had not cleared the initially detected HPV infection, and these were considered persistent. We found here an association between multiple HPV infections and high viral loads with and infection persistence. Our findings suggest there are benefits in ascertaining viral load and multiple HPV infections status of HR-HPV infections for predicting the risk of persistence, a requirement for developing CC. These findings contribute to our understanding of HPV epidemiology and may allow screening programs to better assess the cancer-developing risks associated with individual HR-HPV infections.