Symptom attribution and clinical decision-making among general practitioners relating to lung cancer investigations for patients with pre-existing COPD: a vignette study

Problem

It is essential that patients presenting to their general practitioner (GP) with symptoms possibly associated with lung cancer are promptly referred for diagnostic investigations. The presence of a pre-existing chronic condition (also termed comorbidity) may delay cancer diagnosis, as the comorbidity might provide alternative explanations or be prioritised over symptom investigation. Chronic Obstructive Pulmonary Disorder (COPD) is a degenerative condition which impacts the lungs and shares many symptoms with lung cancer. As patients with COPD are at increased cancer risk, it is important to understand clinical decision-making regarding investigations for a possible lung cancer in general practice. We aimed to investigate the role of pre-existing COPD on GP symptom attribution and clinical decision-making in relation to lung cancer diagnosis.

Approach

An online cross-sectional vignette survey was conducted with a panel of UK GPs. Four vignettes were developed which described general symptoms (weight loss and fatigue) or respiratory symptoms (breathlessness and cough) in patients with or without COPD. In an online survey, GPs were asked to read the vignettes and provide the first, second and third most likely diagnoses in a free-text box. GPs were also asked to select up to 4 referral actions from a pre-coded list. Free-text responses on symptom attribution were examined using content analysis. Binomial and multinomial logistic regressions were used, including cluster-robust standard errors. The primary outcomes of interest were the attribution of symptoms to a lung cancer and selection of an urgent chest x-ray referral (as recommended by current UK NICE guidelines). Analyses were conducted on overall (i.e. GP attributed symptoms to lung cancer at any likelihood) and ‘most likely’ attribution.

Findings

422 vignettes were completed by 109 GPs. Lung cancer was the most frequent attribution for patients presenting with general symptoms, with no difference by COPD status (61.32% for those with and 62.62% for those without COPD at the ‘most likely’ level). For patients presenting with respiratory symptoms, the most frequent attribution was COPD for patients with the comorbidity (48.57%) and ‘other respiratory conditions’ for patients without (47.12%). General symptoms were a significant predictor of lung cancer attribution regardless of COPD status (OR= 2.44, 95% CI 1.39 – 4.26). Attribution of lung cancer as the ‘most likely’ cause of symptoms was the only significant predictor of urgent chest x-ray referral (OR = 2.63, 95% CI = 1.31 – 5.25).

Consequences

In our study, COPD status did not play a role in influencing GP symptom attribution or referral action, despite the higher risk of lung cancer associated with COPD. It is important for GPs to consider the possibility of an underlying cancer in patients who present with respiratory symptoms, particularly for those with COPD, as such symptoms were often attributed to the comorbidity which may delay necessary diagnostic investigations.