CANCER SYSTEM INDICATOR SNAPSHOTS Provincial rates and time trends in pancreatic cancer outcomes

trends over time. The resulting trends were quantified as annual percent change (apc), with a positive or negative apc corresponding to an increased or decreased trend respectively. The 5-year conditional relative survival4, which describes the probability of a patient surviving to a given time in the future during the cancer experience (5 years in this case) relative to the expected survival of the general population of the same age and sex, was calculated. Pancreatic cancer was defined using the site code C25 (International Classification of Diseases for Oncology, 3rd edition) for incidence and the site code C25 (International Classification of Diseases for Oncology, 9th and 10th editions) for mortality.


INTRODUCTION
Pancreatic cancer, often called the "silent killer," is the twelfth most common cancer in Canada, with an estimated 4600 new cases in 2012 1 .Surpassing prostate cancer, pancreatic cancer is also the fourth leading cause of cancer-related death in Canada, with an estimated 4300 deaths in 2012 1 .Smoking, obesity, diabetes, and genetic predisposition are all known risk factors for pancreatic cancer.Currently, no early detection method and no effective treatment are available for pancreatic cancer 2 .Of all patients diagnosed with pancreatic cancer, 75% die within the first year, most within the first 3-6 months 2 .The objective of the present article is to highlight the outcomes of this highly fatal cancer.Further details on the results and on the methodologies used can be found in the 2012 Cancer System Performance Report released by the Canadian Partnership Against Cancer as part of the system performance initiative.

METHODS
Cancer incidence data (the number of newly diagnosed cases) from 1992 to 2009 (to 2007 for Quebec) were extracted from the Canadian Cancer Registry, a population-based database maintained by Statistics Canada.Mortality (number of deaths) through December 31, 2009, was determined using record linkage to the Canadian Vital Statistics Death Database (excluding deaths registered in the province of Quebec) and information reported by provincial and territorial cancer registries 3 .
Incidence and mortality rates were age-standardized to the Canadian 1991 standard population.The age-standardized incidence rate (asir) and age-standardized mortality rate (asmr) allow for a comparison of rates over time and across provinces in which age structures differ.Trends in asir and asmr were examined using piecewise linear regression analysis, a technique that identifies changes in Current OnCOlOgy-VOlume 20, number 5, OCtOber 2013 Copyright © 2013 Multimed Inc.Following publication in Current Oncology, the full text of each article is available immediately and archived in PubMed Central (PMC).
Quebec, the number of deaths attributable to pancreatic cancer surpassed those attributable to prostate cancer as early as 1998.In 2009, deaths caused by prostate cancer still outnumbered those caused by pancreatic cancer in Alberta, Manitoba, and Saskatchewan (data not shown).

Relative Survival
Despite significant advancements in detection and treatment for some cancers, no effective early detection tool is currently available for pancreatic cancer.Most pancreatic cancer cases are detected at the advanced stage, leading to a 5-year survival rate in the single digits 2 .
Using pooled data for 2005-2007, the crude 5-year overall relative survival ratio for pancreatic cancer in Canada (excluding Quebec) was 9%.The percentage varied by province, from 3% in Manitoba to 12% in Newfoundland and Labrador (Figure 3).Caution should be used when comparing the relative survival ratio across provinces.Under-ascertainment of deaths because of linkage failure of registry data with death certificates or because of unregistered annual emigration could lead to severe overestimation of survival, because patients lost to follow-up are assumed to be alive at the cut-off date 5 .This limitation has a much greater effect on estimates for people in younger and middle-aged groups.It could be one reason for the double-digit crude 5-year relative survival ratios in Ontario and Newfoundland and Labrador.
With increasing crude numbers of new cases and deaths on the horizon, pancreatic cancer will become a significant cancer burden for the nation.

THE CANCER SYSTEM PERFORMANCE COLLABORATION
The Cancer System Performance Report is published by the Canadian Partnership Against Cancer and  The 2012 Cancer System Performance Report can be viewed at http://www.cancerview.ca/systemperformancereport.
Slides of figures in this communication and the Cancer System Performance Report can be downloaded at http://www.cancerview.ca/downloadableslides.

figure 1
figure 1 Age-standardized (to the Canadian 1991 standard population) incidence and mortality rates for pancreatic cancer, by sex, Canada, 1992-2009.Data source: Statistics Canada, Canadian Cancer Registry, Vital Statistics Death Database.
made possible through the dedicated efforts of the System Performance Steering Committee and the Technical Working Group for System Performance, comprising representatives from each of the 10 provincial cancer agencies, programs, and directorates.