High-risk Human Papilloma Virus (HPV) is a major risk factor for cervical dysplasia and cancer. The current quadrivalent vaccine introduced in the National Vaccination Programme, with a coverage rate of 85%, will provide only some protection against cervical cancer, when it is linked to HPV 16/18. The objective of this study was to assess the potential impact of an HPV nonavalent vaccine is diminishing the cervical cancer burden.
An observational, retrospective, cross-sectional analysis was conducted to evaluate the distribution of high risk HPV genotypes among women with a cervical cancer who were referred and submitted to surgery in the Gynecological Department of Lisbon´s Oncology Institute, from January 2012 to December 2015.
A hundred and ten patients (mean age 49,45 ± 10.95 years) were included. Ninety two were HPV positive (83.6%). The majority of these tested positive for HPV 16 (67.4%) followed by HPV 18 (9.8%). A single HPV infection was present in 72.8%. The five most frequent types were HPV 16 (67.4%), HPV 18 (9.8%), HPV 33, HPV 53 and HPV 58 (6.5%). Multiple HPV types were present in 27.2%, with two HPV types in 17.4%, three HPV types in 7.6% and four or more HPV types in 2.2%. HPV type prevalence was 97.1%, 98.5%, 96.6% and 96.3% among low and high squamous intraepithelial neoplasia (LSIL and HSIL), adenocarcinoma (AC) and squamous cell carcinoma (SCC) cases, respectively. The most common HPV type in HSIL were HPV 16/53/33 (53.5/9.3/4.7%) and in invasive cervical cancer (ICC) were HPV 16/18/58 (53.7/13.0/5.6%). In SCC the more frequent HPV identified were HPV 16/33/52 (66.9/5.7/5.7%) and in AC HPV 16/18/31 (46.7/13.3/6.7%). The positive rates of the HPV high-risk types (HPV 16 and 18) included in current prophylactic vaccines, represented 65.4% of women with SCC, 70.0% with AC, 100% with other type of ICC, as well as 53.6% with HSIL and 28.6% of LSIL cases. The nonavalent vaccine that includes 5 more HPV types (31/33/45/52/58) will cover 84.6% of the SCC, the same percentage of AC, 67.9% of HSIL and 57.1% of LSIL cases in our sample.
This study showed that in our population the nonavalent vaccine would potentially prevent more 7.7% of SCC. It might also potentially reduce the rate of HSIL in 14.3% and LSIL in 28.5%. Ideally if HPV 53 could be included, this reduction could be potentialized: more 11.5% of SCC cases, representing a coverage of 92.3%, and more 10.7% of HSIL, representing a coverage of 78.6%.
National registry is needed in order to follow the trends of specific HPV types in portuguese society and to evaluate the potential impact of profilatic measures, especially the use of HPV vaccines.