Population based colorectal cancer survival among patients diagnosed in 1985–89 was lower in Europe than in the USA (45% vs 59% 5 year relative survival).
Dr Ciccolallo and colleagues undertook a study in order to explain this difference in survival using a new analytic approach for patients diagnosed between 1990 and 1991.
Researchers gather information on a total of 2, 492 European and 11, 191 US colorectal adenocarcinoma patients who had been registered by 10 European and 9 US cancer registries.
The researchers obtained clinical information on disease stage, number of lymph nodes examined, and surgical treatment.
The research team analyzed 3 year relative survival, calculating relative excess risks of death (RERs, referent category US patients) and adjusted for age, sex, site, surgery, stage, and number of nodes examined, using a new multivariable approach.
| After adjusting for age, sex, and site, the research team found that the relative excess risk was significantly high in all 10 European populations|
The researchers found that 85% of European patients and 92% of US patients underwent surgical resection.
The investigators noted that 3 year relative survival was 69% for US patients and 57% for European patients.
After adjustment for age, sex, and site, the research team found that the RER was significantly high in all 10 European populations, ranging from 1.07 (Modena, Italy) to 2.22 (1.79–2.76) (Thames, UK).
After further adjustment for stage, surgical resection, and number of nodes examined (a determinant of stage), the researchers noted that RERs ranged from 0.77 to 1.59.
For some European registries the excess risk was small and not statistically significant.
Dr Ciccolallo concluded, "US-Europe survival differences in colorectal cancer are large but seem to be mostly attributable to differences in stage at diagnosis."
"There are wide variations in diagnostic and surgical practice between Europe and the USA."