Comparison of cancer diagnostic intervals before and after implementation of NICE guidelines: analysis of data from the UK General Practice Research Database

Background: The primary aim was to use routine data to compare cancer diagnostic intervals before and after implementation of the 2005 NICE Referral Guidelines for Suspected Cancer. The secondary aim was to compare change in diagnostic intervals across different categories of presenting symptoms. Methods: Using data from the General Practice Research Database, we analysed patients with one of 15 cancers diagnosed in either 2001-2002 or 2007-2008. Putative symptom lists for each cancer were classified into whether or not they qualified for urgent referral under NICE guidelines. Diagnostic interval (duration from first presented symptom to date of diagnosis in primary care records) was compared between the two cohorts. Results: In total, 37 588 patients had a new diagnosis of cancer and of these 20 535 (54.6%) had a recorded symptom in the year prior to diagnosis and were included in the analysis. The overall mean diagnostic interval fell by 5.4 days (95% CI: 2.4-8.5; P<0.001) between 2001-2002 and 2007-2008. There was evidence of significant reductions for the following cancers: (mean, 95% confidence interval) kidney (20.4 days, - 0.5 to 41.5; P = 0.05), head and neck (21.2 days, 0.2-41.6; P = 0.04), bladder (16.4 days, 6.6-26.5; P <= 0.001), colorectal (9.0 days, 3.2-14.8; P = 0.002), oesophageal (13.1 days, 3.0-24.1; P = 0.006) and pancreatic (12.6 days, 0.2-24.6; P = 0.04). Patients who presented with NICE-qualifying symptoms had shorter diagnostic intervals than those who did not (all cancers in both cohorts). For the 2007-2008 cohort, the cancers with the shortest median diagnostic intervals were breast (26 days) and testicular (44 days); the highest were myeloma (156 days) and lung (112 days). The values for the 90th centiles of the distributions remain very high for some cancers. Tests of interaction provided little evidence of differences in change in mean diagnostic intervals between those who did and did not present with symptoms specifically cited in the NICE Guideline as requiring urgent referral. Conclusion: We suggest that the implementation of the 2005 NICE Guidelines may have contributed to this reduction in diagnostic intervals between 2001-2002 and 2007-2008. There remains considerable scope to achieve more timely cancer diagnosis, with the ultimate aim of improving cancer outcomes.