Despite Mexico's decades-old program of screening for cytologic changes in cervical tissue, cervical cancer remains a significant problem in the country. High-risk human papillomavirus (hrHPV) DNA testing has shown promise as an alternative and specific screening tool, but it's not easy to implement in impoverished areas.

In 2007, the Mexican government's health system introduced an hrHPV DNA testing program that involves vaginal specimens collected by the women themselves at local screening clinics, which offers efficiency and minimizes barriers to care in women with limited access to health services. Word of the program was spread to the community through TV and radio ads.

Samples from 100,242 women were collected between 2007 and 2010. Of these, 10,863 (11%) tested positive for hrHPV and were contacted at home (as many as three attempts were made); 8,267 subsequently underwent colposcopy. An additional 2,399 women with negative hrHPV test results also underwent colposcopy and served as the control group.

Of the hrHPV-positive women who underwent colposcopy, 162 were diagnosed with cervical intraepithelial neoplasia 2 or 3 (CIN2+) and 55 were diagnosed with invasive cancer. In com-parison, only three of the 2,399 women in the control group had CIN2+ and none had invasive disease.

Although the study authors believe these results clearly indicate that testing self-collected vaginal samples is an effective approach to screening for CIN2+, they point out that 24% of the women with positive test results did not undergo colposcopy, which is likely a result of several factors: difficulties with transportation, prohibitive costs, inconvenient clinic hours, and the unavailability of child care.

Given the low rate of CIN2+ cases among women positive for hrHPV and limited colposcopy services, the authors suggest that interventions such as cervical cytologic testing (Papanicolaou testing), HPV type 16 (and possibly HPV type 18) genotyping, or testing for biomarkers could be used before a colposcopy is conducted. They recommend a registry-based system for the screening program to help ensure that women needing follow-up receive the appropriate services.

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