Pancreatic cancer epidemiology and survival in an Australian population

Abstract

South Australian registry data were used to explore age-standardised incidence and mortality rates and case survivals for pancreatic cancer during 1977 to 2006. Disease-specific survivals were investigated using Kaplan-Meier estimates and Cox proportional hazards regression. While annual incidence and mortality rates were relatively stable among males during 1983-2006, they were 14% and 17% lower respectively than for the 1977-82 baseline. A converse non-significant secular trend was suggested in females, in that incidence in 1989-2006 was 10% higher than in 1977-88, with a corresponding 9% increase in mortality. As a result, male to female incidence rate ratios decreased from 1.73:1 in 1977-82 to about 1.34:1 in 2001-06. One-year survival was 18.0% but this figure decreased to 3.6% at five years. Higher survivals were evident for more recent diagnostic periods, with one-year survival increasing from 14.3% in 1977-88 to 23.9% in 2001-06. Multivariable proportional hazards regression indicated that case fatality was higher in the older age groups and lower for neuroendocrine than other histology types, patients from high and mid-high than lower socio-economic areas, and for more recent diagnostic periods. The differences by diagnostic period, socio-economic status and histology type applied both to the age range less than 60 years and between 60 and 79 years, but were not evident in older patients. The divergent secular trends in incidence and mortality in males and females and associated decreases in male to female rate ratio are consistent with trends in the USA and likely reflect differences in historic tobacco smoking trends by sex. While survival at five years from diagnosis is still only about 5%, patients are living longer with more surviving one year or more, probably due to gains in treatment and potentially in diagnostic technology.