The aim of this research is to explore changes in time to diagnosis and diagnostic activity from 2000-2015 and to estimate the early impact of the NICE 2015 guidelines for suspected cancer.
We will use individual patient-level data to estimate the explore changes in time to diagnosis and diagnostic tests a) over time b) by comparing patients with NICE-qualifying symptoms to those without, and c) by comparing cancers with new NICE recommendations in 2015 to those with unchanged recommendations. The latter groups capture the background influences affecting outcomes, and therefore act as a 'control' group, allowing us to measure the additional impact of the guidelines on patients with NICE-qualifying symptoms. Throughout this research process we will explore ways in which we might semi-automate the monitoring process for the future.
Diagnostic activity (including investigations and referrals for suspected cancer) has increased progressively between the 2005 and 2015 NICE guidance, perhaps influenced by the research evidence on which the guidelines were based. This analysis is necessary to document the degree by which times to diagnosis have changed in the last few years, and to establish benchmarks for subsequent evaluation of any changes following the 2015 guidance.
The objectives of the study are to explore changes in diagnostic interval and diagnostic activity of cancers from 2000-2015, and to estimate the early impact of the NICE 2015 suspected cancers guidelines.
We will examine 13 cancers diagnosed since 2000: lung, oesophagus, stomach, pancreas, colorectal, breast, ovary, uterus, prostate, bladder, kidney, melanoma and myeloma. These cancers, including all the common ones, are those for which the 2015 guidelines made a major alteration in recommendations from the previous 2005 guidance, so the impact of the 2015 guidelines, should arise primarily within these 13 cancers. For other cancers, little or no change was made, and so we check this by studying a further 10 cancers to see if any change has arisen over the same time period.
We will use a difference in differences approach to estimate the impact of the new policy on outcomes for patients with NICE-qualifying symptoms relative to those without. Linear and quantile regression models will be fitted to compare the mean and quantile diagnostic interval between the cohorts, using tests of interaction to compare changes in our primary outcome, diagnostic interval, between presentation of NICE-qualifying symptom alone or in combination and presentation of non-NICE-qualifying symptom.
Health Outcomes to be Measured:
Diagnostic interval, stage at diagnosis, treatment with curative intent, survival
Cancer Registration Data;ONS;Patient Townsend