Diagnostic intervals in breast, colorectal, lung, pancreatic, oesophageal and gastric cancers 2001-2 and 2007-8: database study

Background
As part of the National Awareness and Early Diagnosis Initiative, we undertook a database study to determine and compare diagnostic intervals of different cancers both before and after the introduction of the 2005 NICE urgent cancer referral guidelines. This would also provide a benchmark of current practice.

Method
We analysed data from the General Practice Research Database. Patients with breast, colorectal, lung, pancreatic, oesophageal or gastric cancers, aged 40 or more and diagnosed in either 2001-2 or 2007-8 were included. Symptoms that may represent potential cancer symptoms for each cancer were predetermined by an expert group, using evidence from the literature. Diagnostic intervals (the times from first presentation to diagnosis) were calculated for both cohorts for each cancer, and compared using the Mann-Whitney U test.

Results
The results were (median diagnostic intervals, IQR and 90th centiles, p values):
Breast: 2001-2 (n=733), 27 days, 14-58, 151; 2007-8 (n=902), 24.5 days, 14-52, 140, p=0.3916.
Colorectal: 2001-2 (n=1491), 85 days, 37-173, 266; 2007-8 (n=2142), 66 days, 33-144, 251, p=0.0000.
Lung: 2001-2 (n=1047), 85 days, 38-193, 288; 2007-8 (n=1557), 85 days, 35-195, 299, P=0.9711.
Pancreas: 2001-2 (n=336), 57 days, 24-137, 266; 2007-8 (n=454), 46 days, 21-108, 207, p=0.0573.
Oesophagus: 2001-2 (n=555), 59 days, 26-146, 265; 2007-8 (n=761), 48 days, 26-111, 232, p=0.0103.
Stomach: 2001-2 (n=415), 88 days, 38-197, 289; 2007-8 (n=562), 77 days, 33-185, 300, p=0.2888.

Conclusion
For five of the six cancers, diagnostic intervals reduced between 2001-2 and 2007-8, although only significantly for colorectal and oesophagus; lung remained unchanged. The introduction of the NICE guidelines is one explanation, though other factors may well apply. Diagnostic intervals remain long in some cancers with long tails to their distribution, and contribute to the UK’s poorer cancer outcomes. There remains much potential to achieve more timely diagnoses in these cancers.