Colorectal cancer survival in the USA and Europe: a CONCORD high-resolution study

Abstract

Objectives: To assess the extent to which stage at diagnosis and adherence to treatment guidelines may explain the persistent differences in colorectal cancer survival between the USA and Europe.

Design: A high-resolution study using detailed clinical data on Dukes' stage, diagnostic procedures, treatment and follow-up, collected directly from medical records by trained abstractors under a single protocol, with standardised quality control and central statistical analysis.

Setting and participants: 21 population-based registries in seven US states and nine European countries provided data for random samples comprising 12 523 adults (15-99 years) diagnosed with colorectal cancer during 1996-1998.

Outcome measures: Logistic regression models were used to compare adherence to 'standard care' in the USA and Europe. Net survival and excess risk of death were estimated with flexible parametric models.

Results: The proportion of Dukes' A and B tumours was similar in the USA and Europe, while that of Dukes' C was more frequent in the USA (38% vs 21%) and of Dukes' D more frequent in Europe (22% vs 10%). Resection with curative intent was more frequent in the USA (85% vs 75%). Elderly patients (75-99 years) were 70-90% less likely to receive radiotherapy and chemotherapy. Age-standardised 5-year net survival was similar in the USA (58%) and Northern and Western Europe (54-56%) and lowest in Eastern Europe (42%). The mean excess hazard up to 5 years after diagnosis was highest in Eastern Europe, especially among elderly patients and those with Dukes' D tumours.

Conclusions: The wide differences in colorectal cancer survival between Europe and the USA in the late 1990s are probably attributable to earlier stage and more extensive use of surgery and adjuvant treatment in the USA. Elderly patients with colorectal cancer received surgery, chemotherapy or radiotherapy less often than younger patients, despite evidence that they could also have benefited.

Keywords: Epidemiology; Public Health; Statistics & Research Methods.

Figure 1

Five-year age standardised net survival (%), patients diagnosed with primary invasive colorectal cancer in Europe and the USA in the late 1990s: country and region. Note—Northern Europe: Finland; Western Europe: France (Côte d'Or) and the Netherlands (North East Netherlands); Southern Europe: Italy (Genova, Ragusa and Varese), Slovenia and Spain (Granada, Navarra and Tarragona); Eastern Europe: Estonia, Poland (Cracow and Kielce) and Slovakia.

Figure 2

Five-year age-standardised net survival (%), patients diagnosed with primary invasive colorectal cancer in Europe and the USA in the late 1990s: region* and stage at diagnosis. *Northern Europe: Finland; Western Europe: France (Côte d'Or) and the Netherlands (North East Netherlands); Southern Europe: Italy (Genova, Ragusa and Varese), Slovenia and Spain (Granada, Navarra and Tarragona); Eastern Europe: Estonia, Poland (Cracow and Kielce) and Slovakia.