Mauricio Hernández

Comparison of HPV-based assays with Papanicolaou smears for cervical cancer screening in Morelos State, Mexico

Objective: To compare the performance of human papillomavirus (HPV) assays with conventional Pap cytology for cervical cancer (CC) screening in Mexico. Methods: Pap smears, self-collected vaginal specimens (SS) for HPV testing, and clinician-collected cervical specimens (CS) for HPV testing were obtained from 7868 women, aged 15–85 years old, attending CC screening at the Mexican Institute of Social Security (IMSS) between May and October, 1999. SS and CS specimens were screened for oncogenic HPV DNA by Hybrid Capture 2. Women who received cytological interpretations of atypical squamous cells of undetermined significance (ASCUS), and/or a positive HPV test were referred for colposcopy and histologic studies. The relative estimates for sensitivity, specificity and predictive values of each test were calculated using histological diagnoses of cervical intraepithelial neoplasia (CIN) grades 2 or 3, or CC histological diagnosis. Results: Oncogenic HPV detection rate was 11.6% for SS, and 9.3% for CS. Pap smear abnormalities were observed in 2.4% of the women. Of 1147 women who had at least one abnormal test result, 88.5% underwent colposcopy, and 101 biopsy-confirmed CIN2/3 or cancer cases were identified. The relative sensitivity estimates for the Pap test, SS and CS were 59.4% (95% CI: 49.2–68.9), 71.3% (95% CI: 61.3–79.6), and 93.1% (95% CI: 85.8–96.9), respectively, while the specificities were 98.3% (95% CI: 98.0–98.6), 89.2% (95% CI: 88.5–89.9), and 91.8% (95% CI: 91.2–92.4), respectively. The positive predictive values of Pap, SS and CS were 36.1, 9.1 and 14.9, the colposcopy referrals needed to detect a case of CIN2/3 or cancer were 2.8, 11.0 and 6.7, respectively. Discussion: Both HPV assays detected more cases of CIN2/3 or CC than Pap cytology alone. However, the HPV assays increased the number of colposcopy referrals. Our study suggests that HPV testing could be an effective way to improve the performance of CC screening.

Improving cervical cancer screening in Mexico: results from the Morelos HPV Study

OBJECTIVEnThe purpose of this paper is to describe some of the results of the Morelos HPV Study. The main objective of the Morelos HPV Study is to evaluate the use of human papillomavirus (HPV) DNA testing, as compared to the Papanicolaou (Pap) test, for cervical cancer (CC) screening.nnnMATERIAL AND METHODSnThe Morelos HPV Study is currently being conducted in Mexico, to examine the possibility of using HPV testing for CC screening. The HPV testing of self-collected vaginal and clinician-collected cervical specimens was evaluated as part of this study. The acceptability of the HPV testing of self-collected specimens was compared to that of the Pap test. A cost-effectiveness analysis (CEA) and cost-benefit analysis (CBA) was also performed.nnnRESULTSnThe Morelos HPV Study results indicate that HPV testing has a greater sensitivity to detect cervical intraepithelial neoplasia (CIN) 2/3 and CC than the Pap test. Our results also indicate an over-all lower acceptability of the Pap test as compared to the self-collected procedure. The results of the CEA and CBA indicate that screening women between the ages of 20-80 for CC using some type of HPV testing is always more cost-effective than screening for CC using the Pap test.nnnCONCLUSIONSnOur results suggest that self- and clinician-collected HPV testing could be used in CC prevention programs, as an effective complement or substitute for the Pap test. This paper is available too at: http://www.insp.mx/salud.index.html.

Design and methods of the evaluation of an HPV-based cervical cancer screening strategy in Mexico: the Morelos HPV study

OBJECTIVEnThe purpose of this paper is to describe the design and methodology of the Morelos HPV Study. The main objective of this study is to examine the use of two different methods for obtaining HPV DNA specimens, self-collected vaginal and clinician-collected cervical, to detect pre-invasive cervical lesions and cancer.nnnMATERIAL AND METHODSnThis study was conducted within the regular population-based framework of the Mexican Institute of Social Security (IMSS) cervical cancer screening program in Morelos. A total of 7,868 women were recruited between May and October 1999 and are representative of the population of women attending cervical cancer screening services at the 23 IMSS clinics in the state of Morelos in 1999. Women were provided with a detailed description of the study before signing an informed consent form. Basic data were obtained from all participants using a standard IMSS registration form. During the initial recruitment visit, a randomly selected subsample of 1,069 participants were interviewed to collect additional information about cervical cancer risk factors, acceptability of the HPV and Pap tests, as well as patient costs. Before the pelvic exam, participants were asked to provide a self-collected vaginal specimen for HPV testing. All participants underwent a pelvic examination that involved collecting a cervical sample for the Pap smear and a clinician-collected HPV specimen. Data were evaluated from 7,732 women with complete information for the three tests. The 1,147 women who received at least one positive result (Pap, self- and/or clinician-HPV tests) were invited to return for a colposcopic examination. During colposcopy, biopsies were taken as appropriate, to histologically confirm a diagnosis of cervical intraepithelial neoplasia (CIN) 2/3 or invasive cancer. A total of 1,015 women attended colposcopy, and 101 women received a histologically-confirmed CIN 2/3 or cervical cancer diagnosis.nnnCONCLUSIONSnThe initial enrollment activities of the Morelos HPV study are the basis for a prevalent case-control study and a prospective cohort study that will investigate the natural history of HPV infections and determine if an HPV-based screening strategy is a safe and cost-effective alternative to Pap screening. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Risk factors for cervical cancer among HPV positive women in Mexico

OBJECTIVEnTo identify factors that are associated with an increased risk of developing high-grade cervical intraepithelial neoplasia (CIN) or cancer among human papillomavirus (HPV)-positive women in Mexico.nnnMATERIAL AND METHODSnA case-control study design was used. A total of 94 cases and 501 controls who met the study inclusion criteria were selected from the 7 732 women who participated in the Morelos HPV Study from May 1999 to June 2000. Risk factor information was obtained from interviews and from HPV viral load results. Odds ratios and 95 percent confidence intervals were estimated using unconditional multivariate regression.nnnRESULTSnIncreasing age, high viral load, a young age at first sexual intercourse, and a low socio-economic status are associated with an increased risk of disease among HPV-positive women.nnnCONCLUSIONSnThese results could have important implications for future screening activities in Mexico and other low resource countries.