Cervical, vaginal and vulvar cancer incidence and survival trends in Denmark, Finland, Norway and Sweden with implications to treatment

BACKGROUND: Incidence of cervical cancer has been reduced by organized screening while for vaginal and vulvar cancers no systematic screening has been implemented. All these cancers are associated with human papilloma virus (HPV) infection. We wanted to analyze incidence trends and relative survival in these cancers with specific questions about the possible covariation of incidence, survival changes coinciding with incidence changes and the role of treatment in survival. We used nationwide cancer registry data for Denmark (DK), Finland (FI), Norway (NO) and Sweden (SE) to address these questions. METHODS: We use the NORDCAN database for the analyses: incidence data were available from 1943 in DK, 1953 in FI and NO and 1960 in SE, through 2016. Survival data were available from 1967 through 2016. World standard population was used in age standardization. RESULTS: In each country the incidence of cervical cancer declined subsequent to rolling out of screening activities. The attained plateau incidence was lowest at 4/100,000 in FI and highest at 10/100,000 in DK and NO. The incidence of vaginal and vulvar cancer remained relatively constant at about 2/100,000. Relative 1-year survival in cervical cancer improved in all countries from low 80%s to high 80%s in the 50-year period, and 5-year survival improved also but at 20% units lower level. Survival gains were found only in patients diagnosed before age 60 years. Survival in vaginal and vulvar cancer followed the same patterns but at a few % units lower level. CONCLUSION: Cervical cancer screening appeared to have reached its limits in the Nordic countries by year 2000. Novel treatments, such as immunotherapy, would be needed to improve survival until HPV vaccination will reach population coverage and boost the global fight against these cancers.