Exploring the impact of the NICE guidelines for suspected cancers on diagnostic interval and resource use within GP practices

Start Date Jul 2017

Code E7-Aff

Status Ongoing

Project Lead
Senior Lead


UK primary-care referral guidance published by The National Institute for Health and Clinical Excellence (NICE) describes the signs, symptoms, and test results (“features”) of undiagnosed cancer. In 2015 (2011 for ovarian cancer), the NICE guidance was revised to liberalise investigation, by introducing more features representing a low-risk of undiagnosed cancer.  To some extent, the revised NICE guidelines codified trends in clinical practice.

Our study used observational primary-care data from the Clinical Practice Research Datalink (CPRD) to explore trends over the period 2006–2017 in: (a) the time to diagnosis (clinical arm) and (b) diagnostic activity (health economics arm) for adults with cancer.

We hypothesised that times to diagnosis would reduce over time for participants presenting with features newly introduced during guidance revision, as evidence on these low-risk cancer features emerged and was translated and codified into practice by the revised guidance.

We explored trends in diagnostic activity over the period 2006–2017.

Aims & objectives

The aims of this research are to:

Explore changes over the period 2006-2017 in: (a) time to cancer diagnosis and (b) cancer diagnostic activity for 11 common cancer sites for which new features of undiagnosed cancer were introduced during guidance revision, to:


The CPRD provided electronic medical records for 83,935 adults with an incident diagnosis of myeloma or bladder, breast, colorectal, lung, oesophageal, ovarian, pancreatic, prostate, stomach or uterine cancer between 1 January 2006 and 31 December 2017. Participants were grouped by their first presenting (index) feature of their undiagnosed cancer in the year before diagnosis:

For analysis of time to diagnosis, the outcome variable was diagnostic interval (number of days from index feature to diagnosis).  Semiparametric varying-coefficient analyses compared diagnostic intervals between New-NICE and Old-NICE groups over the period 1 January 2006 to 31 December 2017.

For resource use, diagnostic tests ordered in primary care will be identified, and trends in the quantity and costs will be explored over the period 1 January 2006 to 31 December 2017. Potential methods for identifying the impact of guidance revision include difference-in-difference analyses.

Outputs & impact

To date the outputs include:

A further health economics publication on the impact of revised NICE guidance on diagnostic activity is planned.

Next steps

Now that the clinical arm of this study is complete, the focus has moved to the health economics analyses, which are planned for completion in 2020.


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