Data were used from the General Practice Research Database, now known as the Clinical Practice Research Datalink, from 1 January 2000 to 31 December 2009 inclusive. General practices contribute to the database from around the UK and adhere to stringent data quality recording standards.8
Patients had an incident breast, colorectal, or lung cancer; were ≥40 years at diagnosis; and had ≥1 year of prior registration data. These cancers were chosen because they are common and GP personal knowledge of the patient may be more (for example, fatigue in colorectal or lung cancer) or less useful (for example, breast cancer, most commonly presenting with a breast lump). Patients were excluded if they had an in-situ cancer, their recorded date of death was before or the same as their diagnosis date, or they were asymptomatic (no recorded cancer symptom/sign) in the 12 months before diagnosis. Analyses were further restricted to consultations where symptoms or signs were recorded in consultations with GPs (partner, salaried, registrar, or locum) in relevant types of encounter (mainly surgery, telephone, or home visit). The few male patients in the breast cancer dataset were also excluded.
How this fits in
Continuity of care is a core value in general practice yet, nowadays, patients are less likely to see the same doctor. It is unknown whether seeing the same doctor leads to a faster or slower diagnosis of cancer among patients who present with symptoms. Overall, this study found that any effect of patient–doctor continuity on time to diagnosis of breast, colorectal, or lung cancer was small. While GPs should be cautious not to dismiss potentially significant symptoms or signs among patients they know well, it may be prudent for doctors to personally follow-up patients with ‘low-risk but not no-risk’ symptoms.
Relevant symptoms and signs (classified as high-risk or low-risk) for each cancer (Table 1) were based on the National Institute for Health and Care Excellence Referral Guidelines for Suspected Cancer.9 These were updated by reference to recent systematic reviews on colorectal cancer10 and breast cancer;11 and a case–control study of lung cancer.12 Symptoms and signs were identified using Read Codes only, which were independently identified and agreed by the GPs on the team. High-risk took precedence over low-risk symptoms or signs where both were recorded in the index consultation. The presence or absence of risk factors for each type of cancer were also identified: family history (breast cancer); ulcerative colitis (colorectal cancer); and current/ex-smoker or chronic obstructive pulmonary disease (lung cancer). Referrals, appropriate to each cancer, were identified for ‘definitive’ investigations (for example colonoscopy for colorectal cancer) or secondary care opinion (for example respiratory physician for lung cancer).
The list of diagnostic codes used has been developed previously as part of DISCOVERY (http://discovery-programme.org/; a 5-year programme of work designed to improve the diagnosis of cancer) and has supported several publications.13–18 Patient multimorbidity was quantified by a simple count of 17 chronic diseases included in the clinical domain of the Quality and Outcomes Framework, as at 2007–2008, using methods described previously.19