Background: Population-based studies for gastric adenocarcinoma are scarce, particularly studies conducted within a defined geographical area with publicly available censuses that allow incidence rates to be calculated.
Material and methods: Population-based study in Central Norway from 2001 to 2011, covering a population of 636 000-680 000, respectively. Patients were identified through the Cancer Registry of Norway and the Norwegian Patient Register, and were characterized by data from individual electronic patient records. Outcomes were compared across the early and the late half of the study period.
Results: A total of 878 patients were identified with a median age of 76.2 years. The male to female ratio was 1.72. Annual world age-standardized incidence was 8.0/105 and 3.6/105, respectively. The Lauren diffuse type was significantly more frequent among patients below 60 years, among females and for non-cardia cancers, compared to their counterparts (p < .001). The Lauren mixed type had a stable proportion of around 13% irrespective of age, sex or tumor location. Early gastric cancers (EGC) represented 8.3% of the cases, whereas 44% of all patients were diagnosed with metastatic disease. In males, the proportion of cardia cancers increased from 29.7% to 39.1% during the study period (p = .005). The five-year overall survival was 16%, and was substantially better for the Lauren intestinal type compared to the diffuse type, log-rank p = .003. The R0-R1 resection rate was 39%, with a corresponding five-year survival of 40.9%.
Conclusions: This study provides population-derived data lacking in hospital-based studies. Lauren categories with epidemiological aspects and clinical outcomes are displayed. Gastric cancer was associated with a dismal prognosis. Few patients had EGC and close to 50% had metastatic disease. Many were too old or frail to be considered for surgery.