Reliability of collecting colorectal cancer stage information from pathology reports and general practitioners in Queensland

Objective: To investigate the reliability of collecting colorectal stage information from pathology reports and general practitioners in Queensland, Australia. Methods: A longitudinal study of colorectal cancer survivors conducted in 2003 and 2004 (n=1966, response rate=57%) obtained stage information from clinical specialists (n=1334), general practitioners (GP) (n=1417) and by extracting stage from pathology reports (n=1484). Reliability of stage information was determined by comparing stage from GPs and pathology reports with that reported by the clinical specialists, using a weighted kappa. Results: GPs and pathology reports each had a similar level of agreement with clinical specialists, with kappa scores of 0.77 (0.75-0.80) (n=1042) and 0.78 (0.75-0.81) (n=1152), respectively. Results were similar when restricting to records staged by all three methods (n=847). GPs had similar levels of agreement with clinical specialists within each stage, although pathology reports tended to under-stage patients in Stage D (0.37). Collapsing stage into two categories (A or B, C or D) increased the reliability estimates from the pathology reports to 0.91 (0.88-0.93), but there was little change in GP estimates 0.79 (0.75-0.83). Conclusions: Extractions from pathology reports are a valid source of broad stage information for colorectal cancer. Implications: In the absence of clinical stage data, access to pathology records by population-based cancer registries enables a more accurate assessment of survival inequalities in colorectal cancer survival.