Past and future of prophylactic ablation of the cervical squamocolumnar junction

HPV vaccination has the potential to prevent the vast majority of cervical cancer cases but cervical cancer screening remains the only prevention strategy in adult unvaccinated women. The range of primary screening tests has expanded to include, in addition to cytology, visual inspection with acetic acid (VIA) and HPV-testing. HPV-testing has the best sensitivity and negative predictive value, and a low-cost HPV test may make large-scale high-quality cervical cancer screening possible in low- and medium-income countries (LMICs). However, on account of its low specificity, HPV-testing would impose the additional burden of triaging HPV+ women using cytology, colposcopy, VIA, or other not yet affordable tests. If minimally invasive treatments that have proven efficacious in HPV+ women with cervical intra-epithelial (CIN) grade 2 and 3 lesions also reduced future cervical cancer risk in lesion-free HPV+ women, the treatment of all HPV+ women would become attractive in LMICs in which screening should be performed as infrequently as possible. In the pre-mass screening era, gynaecologists widely practiced prophylactic ablation of the columnar epithelium visible on the ectocervix (ectopy) and squamocolumnar junction (SCJ) in the hope of preventing cervical cancer. Favourable outcomes were reported, especially from Finland, but conclusive results were not reached on account of weaknesses in the study methods. Indirect support for prophylactic ablation is provided by the hypothesis that some cells of embryonic origin derived from the SCJ are the source of high-grade CIN and cervical carcinoma, and that they do not regenerate after SCJ ablation. SCJ cell elimination may avoid neoplastic transformation though not HPV reinfection. Randomised controlled trials are gold-standard, but if not feasible, an evaluation of the impact of prophylactic ablation could be done in the framework of large HPV-based screening programmes. Careful follow-up of lesion-free HPV+ women would provide much needed information on the risk-to-benefit ratio of prophylactic ablation.