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EPIDEMIOLOGY AND CONTROL OF CERVICAL CANCER IN BRAZIL – ROLE OF HPV GENOTYPES
02. Epidemiology and natural history

J.E. Levi, Virology Lab., Instituto de Medicina Tropical da Universidade de Sao Paulo – Sao Paulo (Brazil)

Background / Objectives

The esti­ma­ted age-adjus­ted inci­dence of cer­vi­cal cancer (CC) in Brazil is appro­xi­mately of 18100,000 women/year, with large regio­nal dif­fe­ren­ces. Apart from epi­de­mio­lo­gi­cal inte­rest, reco­gni­zing the role of each indi­vi­dual HPV geno­type in cer­vi­cal mali­gnancy became more important after the intro­duc­tion of HPV vac­ci­nes against HPV 16 or 18 infec­tions, sho­wing limi­ted cross pro­tec­tion to other high-risk geno­ty­pes non-16/18. Not sur­pri­sin­gly, a new genera­tion of vac­ci­nes inclu­ding ano­t­her 5 high-risk HPV geno­ty­pes have recently been laun­ched. Surveillance with exten­ded geno­ty­p­ing plat­forms is necessary to iden­tify an even­tual emer­gence of a non-vac­cine geno­type that may occupy this, to be vacant, eco­lo­gi­cal niche. However, it is clear that the cur­rent vac­ci­nes are highly effec­tive on naïve popu­la­ti­ons but not appro­priate to pre­viously and cur­rent infec­ted sub­jects. This trans­la­tes into the need to screen for CC for the next 50 years. Concerning CC scree­ning, several stu­dies have shown that tes­ting for HPV-DNA is more advan­ta­ge­ous than by cyto­logy. Therefore, many coun­tries are remo­de­ling their CC scree­ning pro­gram, pla­cing HPV tes­ting as the pri­mary tool and refer­ring to cyto­logy only the HPV+ sam­ples. The objec­tive of this work is to inves­ti­gate the dif­fe­ren­tial role of HPV geno­ty­pes in the epi­de­mio­logy of cer­vi­cal cancer in Brazil.

Results

Brazilian stu­dies inves­ti­ga­ting the dis­tri­bu­tion of HPV geno­ty­pes in the gene­ral popu­la­tion and cer­vi­cal cancer spe­ci­mens were reviewed and com­pi­led.

Conclusion

Prevalence of high-risk HPVs in Brazil is simi­lar to coun­tries pre­sen­ting a low inci­dence of CC, indi­ca­ting inef­fi­ci­en­cies in the natio­nal scree­ning pro­gram, which relies on cyto­logy. HPV geno­ty­p­ing in large scale has depic­ted a fre­quency of HPV geno­ty­pes in the gene­ral Brazilian female popu­la­tion that is simi­lar to the global 122490 dis­tri­bu­tion; HPV 16 being the com­mo­nest fol­lo­wed by other geno­ty­pes accord­ing to the study popu­la­tion and geo­gra­phi­cal region, but not HPV 18. In con­trast, on CC cases HPV 18 is the second, being pre­sent on 10–15% of all CCs, far after HPV 16 which accounts for 50–70%.

References

Large stu­dies with pro­lon­ged follow-up revea­led that among HPV geno­ty­pes, clas­si­fied as of high-risk, there are signi­fi­cant dif­fe­ren­ces in their onco­ge­nic poten­tial. Consequently, in the age of per­so­na­li­zed medi­cine, it makes sense to have manage­ment stra­te­gies accord­ing to the geno­type or group iden­ti­fied in the sample. Several bio­mar­kers are under eva­lua­tion in order to iden­tify on HPV posi­tive cer­vico­va­gi­nal sam­ples, those that pre­sent a higher dia­gnostic or pro­gnostic risk of neo­pla­sia, thus jus­ti­fy­ing more costly and inva­sive pro­ce­du­res.