Theme 2 - The Caper Studies

• Lead Investigator: Prof Willie Hamilton
• Co-investigators: Prof Richard Neal, Dr Peter Rose, Dr Fiona Walter
• Researchers: Dr Liz Shepherd, Sally Stapley; Jacqueline Barrett; Sarah Walker

Theme 2 focuses on primary care. It comprises two projects which study the risks of cancer and map current diagnostic pathways. The latter is believed to be the largest investigative study of this kind that has been undertaken in the UK.

Project 2.1 - Quantifying the risk of cancer

The aim is to quantify the risk of a particular type of cancer given the presentation of a particular symptom or diagnostic result, either singly or in combination. We have previously studied colorectal, lung, prostate, ovary and brain tumours, providing accurate estimates of the risk of cancer when an adult patient presents to their GP with a symptom or a combination of symptoms. Thirteen other cancer sites warrant investigation. The long term aim is to study them all, though the Discovery Programme targets an initial 6-8 cancers, beginning with bladder and pancreas. The studies will all employ similar methodologies and analysis.

Design

For each cancer a matched case control study is carried out using data from the General Practice Database (GPRD). This database stores anonymised copies of primary care records from over 12 million UK patients, representative across the whole of the UK. These records contain full details of every consultation, prescriptions, referral and major outcome (such as cancer). The GPRD is large enough to produce statistically valid results even for the low incidence cancers.

Method

Cases will all be patients with cancer who are aged over 40. All the data one year prior to the diagnosis will be examined; previous experience has shown that no variables found more than one year prior to diagnosis were significant. For each case up to seven controls of the same gender, practice and year of birth will be generated.

For each cancer symptom lists will be developed from existing knowledge, the systematic review and primary care laboratory results - which have been transmitted to practices since 2000. The patient records will then be examined to identify occurrences of the symptoms of interest.

Outputs

The project will identify and quantify the main clinical features of those cancers which have been under researched. Each study will produce at least one main research paper and the results will also feed into Theme 3.

Project 2.2 - Mapping diagnostic pathways.

The aim is to identify the routes that patients take to cancer diagnosis.

This project is linked very closely to existing projects within the National Awareness and Early Diagnosis Initiative (NAEDI). There are three strands to this project and the first two are managed within NAEDI. The Discovery Programme will have access to the results of the NAEDI projects as Greg Rubin, Richard Neal and William Hamilton are each members of both. The three strands are:

1. to perform significant event audits in primary care especially to identify cases with diagnostic error.
2. to calculate the intervals between presentation, referral and diagnosis
3. to identify routes to diagnosis

Design

Three cohort studies, using GPRD data, will be carried out on colorectal, lung and pancreatic cancers.

Cases will all be patients with the cancer over 40 years old. The diagnoses will all be since 2007, that is, long after the two week clinics were instituted. Records for the 12 months prior to diagnosis will be examined.

Method

The study identifies the first recorded feature of the cancer in the year before diagnosis, all other recorded symptoms, primary care investigations and referrals. The speciality of referral is identified and non-standard referrals (to specialities other than the correct cancer site) will be highlighted.

Pathways will be identified with diagnostic milestones, including primary care investigations for specific cancers (blood tests, imaging), referrals by speciality, episodes of unscheduled care (out of hours primary care, A & E attendances, secondary care admissions) and inter-consultant referrals.

Outputs

The project will identify and quantify the main routes that patients take to diagnosis. The study will explain the reasons why so few patients take the standard route via two week wait referral from primary care. The results will also feed into Theme 3.