Læknablaðið - 01.03.2016, Blaðsíða 22

R A N N S Ó K N
130 LÆKNAblaðið 2016/102
ENGLISH SUMMARY
Background: In the mid twentieth century gastric cancer was the most
common type of cancer in Iceland. In recent decades, however, the
incidence rate of gastric cancer has decreased markedly and currently
only represents 2-3% of cancer cases. The Laurén classification system
classifies adenocarcinoma into two types, intestinal and diffuse. The
main purpose of our study was to describe the epidemiology of the two
types of gastric adenocarcinoma in Iceland between the years 1990-
2009.
Methods: This is a retrospective cohort study. Information on patients
diagnosed with gastric cancer in Iceland between 1990 and 2009 was
collected from the population based Cancer Registry. Histological
descriptions were reviewed and classified according to the Laurén
classification system. The records of patients diagnosed with either
having intestinal or diffuse adenocarcinomas were reviewed and epi-
demiological information gathered.
Results: Between 1990 and 2009, 730 patients were diagnosed with
gastric adenocarcinoma in Iceland, 447 had intestinal adenocarcinoma
and 168 diffuse adenocarcinoma. Patients diagnosed with diffuse
adenocarcinoma were significantly younger at diagnosis than those
diagnosed with intestinal adenocarcinoma. The sex ratio for intestinal
adenocarcinoma was 2.3:1 (M:F) and 1.1:1 (M:F) for diffuse adenoc-
arcinoma. The incidence of intestinal adenocarcinoma decreased
more rapidly than that of diffuse adenocarcinoma during this period
(0.92/100,000 vs. 0.12/100,000). Median survival rates of intestinal and
diffuse adenocarcinomas were 23.7 and 20.6 months, respectively. The
difference in survival was found to be statistically significant. The hazard
ratio between the two groups was 1.31 (CI 1.03-1.67), corrected for age,
sex, stage, year of diagnosis and surgical outcome (radical, non-radical
or no operation).
Conclusion: The overall incidence rate of gastric cancer has decreased
dramatically in the past 20 years. However, the reduction is largely limi-
ted to the intestinal adenocarcinoma sub-group. We conclude that the
Laurén classification predicts prognosis in gastric adenocarcinoma with
diffuse adenocarcinoma having worse prognosis.
Epidemiology of the two types of gastric adenocarcinoma in Iceland according
to the Laurén histological classification 1990-2009
Halla Sif Ólafsdóttir1, Kristín K. Alexíusdóttir1,2, Sigrún Helga Lund3, Jón Gunnlaugur Jónasson2,4, Þorvaldur Jónsson5,6, Halla Skúladóttir7
1Landspítali University Hospital, Department of Internal medicine, 2Icelandic Cancer Registry, Icelandic Cancer Society, 3Centre of Public Health Sciences, University of Iceland,
4Department of Pathology, Landspítali University Hospital, 5Faculty of Medicine, University of Iceland, 6Landspítali University Hospital, Department of surgery,7Regional Hospital West
Jutland, Herning, Denmark, Department of Oncology.
Key words: gastric cancer, Laurén classification, survival, incidence.
Correspondence: Halla Sif Ólafsdóttir, hsolafsdottir@gmail.com