Cervical Cancer: What Vaccine in Senegal?

Abstract

Introduction: Cervical cancer (CC) is first cancer in terms of frequency and mortality among women in Senegal. This is a public health problem hence the urgency of preventive measures including vaccination. The choice of the vaccine cannot be made on strictly financial factors, nor on the results of the others studies, but should take into account the prevalence and distribution of HPV in the CC in Senegal. We conducted this study with the aim of determining the distribution of the genotype of the different types of HPV found in the CC in Senegal and propose a vaccine for Senegal. Methods: It was a retrospective and descriptive study carried out in cooperation with the molecular and radiobiology institute of Lyon. Sixty paraffin-embedded tissue blocks were chosen by a simple random method on 1015 blocks of CC diagnosed in pathology laboratories of public hospitals of Senegal. In Lyon, the total DNA of the tumor genome was extracted and amplified according to the multiplex PCR technique using primers MY09-MY11, GP5 + and GP6 +. β-globin was used as an internal control. Results: Of the 60 paraffin blocks examined, DNA extraction was unsatisfactory in 4 cases. HPV-HR infection was present in all other tumors. It was a monoinfection in 33 cases (59%) and a multi-infection in 23 cases (41%). In total, of the 56 validated cases, 89 HPV-HR were identified by the PCR-multiplex technique. HPV 16 and 18 accounted for about 70% of all HPV implicated in the CC in Senegal. The other HPV types found are HPV 45 (9), HPV 35 (5), HPV 58 (5), HPV 39 (3), HPV 66 (2), and one case of HPV 31, 33, 51, 59, 68. In 51 patients (91.1%), HPV 16 or 18 was at least one of the viruses involved. Conclusion: The involvement of HPV in CC was first reported by German virologist Harold Zur Hausen in 1980. Several studies have subsequently corroborated this association by finding a stronger binding of HPV to CC than that of tobacco to lung cancer. In 1996, the WHO recognized HPV-HR as the leading cause of CC. There is a variable distribution of HPV in the literature according to geographical and ethnic criteria. In Senegal, as almost everywhere else, HPV 16 and to a lesser degree HPV 18 represent the two major viruses involved in carcinogenesis of the cervix. Of twelve identified viral genotypes, HPV 16 and HPV 18 account for nearly 70% of viral infections and are involved in more than 90% of CC cases. At present, there are three types of vaccines: Cervarix (HPV 16, 18), Gardasil (HPV 6, 11, 16, 18) and Gardasil 9 (HPV 6, 11, 16, 18, 31, 33, 45, 52, 58). The authors recommend the use of Cervarix in the cancer plan of Senegal. They also advise a better sexual education to control the infection and especially the multi-infection found in 40% in the CC in Senegal. Finally, they emphasize that vaccination is not exclusive of screening but rather should accompany it.