A pilot study of HPV DNA and cytology testing in 50,159 women in the routine Mexican Social Security Program - SpringerLink

A pilot study of HPV DNA and cytology testing in 50,159 women in the routine Mexican Social Security Program
Eduardo Lazcano-Ponce1 , Attila T. Lörincz2, Jorge Salmerón1, 3, Irma Fernández4, Aurelio Cruz1, Pilar Hernández1, Ivonne Mejia4 and Mauricio Hernández-Ávila5

(1) Center for Population Health Research, National Institute of Public Health, Avenida Universidad 655, Colonia Sta. Ma, Ahuacatitlán, 62508 Cuernavaca, Morelos, Mexico
(2) Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine, London, United Kingdom
(3) Unidad de Investigación Epidemiológica y en Servicios de Salud, Instituto Mexicano del Seguro Social, Cuernavaca, Morelos, Mexico
(4) Public Health Coordination, Instituto Mexicano del Seguro Social, Mexico, DF, Mexico
(5) Under-Secretariat for Disease Prevention and Control, Secretariat of Health, Mexico, DF, Mexico

Received: 12 November 2009 Accepted: 29 May 2010 Published online: 9 July 2010

Abstract
Introduction
We present a large feasibility evaluation of high-risk HPV (HR-HPV) DNA testing and cervical cytology as a primary screening strategy for cervical cancer precursor lesions in Mexican women, as part of a routine cancer control program (CCP).

Methods
A community-based study was carried out in 50,159 women aged 20–70 years who visited the CCP in 12 federal entities located in Northern, Central, and Southern Mexico, including a total of 48 primary health care units of the Instituto Mexicano del Seguro Social (IMSS). Cervical specimens for cytology and HR-HPV tests were collected at baseline. Women with cytological abnormalities (ASCUS or greater) were referred to colposcopy for further evaluation and treatment if necessary. A subset of HR-HPV-positive women without cervical lesions, in Morelos state, were tested again for HR-HPV DNA within a year, and repeat-positive women were referred to colposcopy.

Results
HR-HPV prevalence among all women was 8.6% (95% CI: 8.3–8.9). Prevalence by age group was 12.2% (95% CI: 11.0–13.3) before 30 years of age and decreased to 7.4% (95% CI: 6.7–8.0) between 46 and 50 years of age. A second minor prevalence peak (8.1%; 95% CI: 7.2–9.0) was observed in women more than 55 years of age. Overall prevalence of cytological abnormalities was relatively low (2.2%; 95% CI: 2.0–2.3) with the highest frequency of abnormal cytology (ASCUS or greater) in the 41–45 year age group (2.5%: 95% CI 2.1–2.7). No correlation between cervical abnormalities and HR-HPV prevalence, by region, was observed. A total of 370 (0.7%) women had an abnormal cytology as well as a positive HR-HPV result; 736 (1.5%) had an abnormal cytology and a negative HR-HPV test; 3,941 (7.9%) women had a positive HR-HPV test and a normal cytology; and 45,112 (89.9%) women were negative in both tests. The first two groups were immediately referred to colposcopy, 72.7% of the women from the cytology-positive and HR-HPV-positive group and 58.0% from the cytology-positive and HR-HPV-negative group successfully completing evaluation. Among the 269 cytology-positive and HR-HPV-positive women, 53 (19.7%) CIN2/3+ cases were detected, whereas among the 427 cytology-positive and HR-HPV-negative participants, only 13 (3.0%) CIN2/3+ cases were documented. In Morelos state, a sample of 287 women with a negative cytology smear and a positive HR-HPV test at baseline were re-screened after ~12 months, by means of cytology and HR-HPV testing. Among these women, 106 (36.9%) were again HR-HPV positive and were referred to colposcopy. Of whom, 76 (71.7%) were successfully evaluated; among these women, 9 CIN2/3+ (11.8%) were documented. Sensitivity of cervical cytology for detecting histologically confirmed CIN2/3+ cases was only 40.0% (95% CI 38.5–41.4) compared to 93.3% (95% CI 92.5–94.0) for HPV DNA testing considering the additional cases detected among women with persistent HPV infection. The specificity of cytology was 97.0 vs. 89.2% for the HPV DNA test.

Discussion
Population-based programs using HR-HPV testing can improve cervical cancer prevention and control in Mexican and other populations where cytological screening is inadequate for detecting precursors of cervical cancer.

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