Delay in diagnosis of lung cancer in general practice

Definitions

Delay in general practice: the time from the patient's presentation of the first symptoms or signs that could be related to the lung cancer until referral to hospital. Delay in general practice was subdivided into: doctor delay: time elapsed without investigation of cancer-related symptoms and signs. System delay: time elapsed due to waiting times related to investigation of cancer-related symptoms and administration. Delays were estimated and in the few cases where estimators disagreed, the cases were discussed until consensus was achieved.

Analyses

We made descriptive statistics of the reasons for delay and calculated P-values (Mann–Whitney), medians and interquartile intervals (IQI) with STATA 8.0.

Presenting symptoms in general practice

The patients presented with many different symptoms. Cough was the most common complaint, followed by dyspnoea, fatigue, fever, and weight loss (Table 1). For 41 of the 84 patients (48.8%) the number of symptoms increased over time between the first presentation and the referral leading to the diagnosis. The distribution of different symptoms did, however, not change (Table 1).

In total, 64 patients (76.2%) presented lung-related symptoms to the GP, that is, coughing, dyspnoea, haemoptysis, or thoracic pain, and these patients experienced a median delay of 29 days (IQI = 12–5 days). Fourteen (16.7%) had atypical symptoms like arthralgia, muscle pain, pain in back or shoulder, or vague symptoms such as fatigue and they had a median delay of 104 days (IQI = 37–199 days). Four patients (4.8%) with symptoms related to brain metastases had a median delay of 24 days (IQI = 9–41 days), and two patients (2.4%) who were diagnosed by chance had 1 and 9 days of delay, respectively.

First action

The GPs' main actions upon first presentation are shown in Table 2. In 26 cases (31.0%), the GP's first action led to a lung cancer diagnosis. Of these, two patients (7.7%) were acutely admitted, one referred (3.8%) to an outpatient clinic, 22 (84.6%) to a chest X-ray and one patient had another investigation. Patients referred after the first consultation or diagnosed by chance had a median delay of 13 days (IQI = 23 days) due to waiting times for chest X-ray and administration.

When first action did not lead to the diagnosis

Among 56 patients not diagnosed after the first consultation, 14 (25.0%) were diagnosed after acute admission and five (8.9%) after referral to an outpatient clinic with respiratory physicians (Table 3). A total of 34 patients (60.7%) were referred to a chest X-ray, the results of which raised suspicion of cancer. There was a 45-day median delay (IQI = 28–111 days) in cases where the GP's first action did not lead to a diagnosis.

Reasons for delay

Summary of main findings

One-third of the patients contacting their GP with signs and symptoms of lung cancer were referred to secondary care upon their first contact, but they experienced a 2-week median delay due to system delay. Patients not diagnosed by the GP's initial actions experienced a median delay of more than 6 weeks. Patients with atypical symptoms had a median delay exceeding 3 months compared with a median delay of 1 month for patients with lung-related symptoms. The median delay for patients with a false negative chest X-ray was nearly six times longer as for patients with a first chest X-ray raising suspicion of cancer. Other important reasons for delay in primary care were: comorbidity, waiting times for investigations, and lack of explicit follow up appointment. Prolonged delay was often due to a combination of reasons. Nearly half of the patients developed new symptoms during the period of delay in general practice, often triggering referral to further investigation and shortening the delay.

One-fifth of the patients waited more than 2 weeks for a chest X-ray and one-tenth waited more than a week to get the result. Blood tests only helped the diagnostic process in a few cases and most often contributed to further delay.

Strengths and limitations of the study

The sample size was relatively small due to the complex data collection and therefore the statistical precision was not great enough to permit stratified analyses. On the other hand, the study is based on detailed information allowing for comprehensive explorations of the delay. The study population included all lung cancer patients in the county, and patients who died shortly after the diagnosis were also included, preventing selection bias. The population-based design strengthens the generalisability of the results.

Primarily using the data from the GP interviews minimised information bias as suggested by the fact that there were no statistically significant differences in any estimation of delay between patients interviewed and patients included post-mortem. The GP-interviews were retrospective which may imply the risk of recall bias. GPs may have wanted to make the length of delay look shorter, when fixing a date for the first encounter, which would tend to underestimate delay, especially doctor delay.

Comparison with existing literature

Other studies have examined delay in diagnosing lung cancer in primary care,7^,11^–14 but have not analysed reasons for delay. An Italian study analysed the association between the presenting symptom and delay in referral to specialist evaluation. The study showed that infections and bloody sputum were capable of speeding up referral, whereas systemic symptoms, cough, and dyspnoea, were the most neglected symptoms and were associated with prolonged delay in referral.15

False negative chest X-rays are known to cause diagnostic delay in lung cancer.16^,17 A recent British study showed that 23% of the patients who had a chest X-ray requested from primary care in the year before the lung cancer diagnosis had a negative chest X-ray.18 The sensitivity of chest X-rays is, however, most often discussed in connection with lung cancer screening.19^,20 We found no other studies exploring the impact of a negative chest X-ray on delay for patients presenting with symptoms in primary care, and the use of X-ray in diagnosing lung cancer may need more research attention.

Watchful waiting is a diagnostic and therapeutic tool in general practice and GPs often tell their patients to return if their symptoms persist or aggravate, assuming that patients will contact the GP again. A recent Dutch study found that patients with head and neck cancer not referred or followed up after their first consultation in primary care were at risk of increased professional delay.21 Several factors were related to delay in returning to the GP: type of symptoms, not being familiar with the symptoms of head and neck cancer, not being suspicious that the symptoms might indicate cancer and generally not being inclined to seek support when facing a problem.

Implications for clinical practice and further research

If we want to reduce diagnostic delay in lung cancer in primary care, one possibility is to reduce waiting times for chest X-rays and other investigations ordered in primary care. Another possibility is to motivate GPs to undertake an earlier reassessment of the diagnosis for the two thirds of patients who are not diagnosed upon their first consultation. This will require that GPs become aware of the low sensitivity of chest X-ray.

Lack of specific follow up appointments was a reason for delay, but the fact that half of the patients experienced symptom progression probably reduced this problem. Further research is needed on how to avoid the delay that occurs when patients who received no diagnosis upon their first consultation have to contact their GP again.