The use of community-based health services associated with lung cancer diagnosis increased rapidly in the 2 months before diagnosis of NSCLC. The key role that GPs play in the diagnosis of lung cancer is highlighted by the findings that in the 3 months to diagnosis 93% attended a GP with 60% of people attending a GP at least four times and a similar proportion having GP-ordered thoracic imaging.

The two most common pathways to diagnosis of NSCLC, accounting for one in three people diagnosed, involved GP and lung specialists in the community without an emergency hospital admission, suggesting patients presenting with less severe or more typical lung cancer symptoms being referred to appropriate specialists. Nevertheless, fewer than half (45%) of people attended a lung specialist (respiratory physician or cardiothoracic surgeon) in the lead-up to diagnosis, which is similar to an earlier NSW study that reported only 53% of people with lung cancer saw a respiratory physician at initial presentation.5 Reasons for not seeing a lung specialist in the community before a diagnosis of NSCLC could include the sudden onset of severe symptoms requiring emergency presentation to hospital (e.g. haemoptysis), referral to a non-lung specialist (e.g. an oncologist or a general physician), referral to a specialist for the presenting symptoms of distant metastases (e.g. a neurologist) or an incidental finding of lung cancer while undergoing investigation for another condition. An Australian study reported that 23% of people with lung cancer were diagnosed incidentally.7 Incidental findings will account for some people diagnosed without GP-ordered imaging or lung specialist attendance in our study.

There were no substantial differences in patterns of GP and specialist attendances and chest imaging for people living in outer regional and remote areas compared with major cities. It appears that remoteness of residence alone is not a major barrier to seeing a lung specialist. However, we had no information on lung cancer MDT membership for the specialists, which may vary by remoteness. Further research is needed to determine whether referral to specialists who are active members of lung cancer MDTs is contributing to higher treatment use and improved outcomes for people diagnosed with lung cancer in major cities.3,17

Overall, one quarter of people had an emergency admission for lung cancer in the lead-up to diagnosis. More than half of these did not have GP-ordered imaging or a lung specialist attendance. A higher proportion of people who had emergency hospitalisations had lung cancer with distant spread compared with those without an emergency admission, suggesting that symptoms of late-stage disease are leading to emergency presentations in some cases. Lung cancer symptoms requiring emergency treatment can occur with little or no prior warning or after a prolonged period without the patient seeking help for milder symptoms.18 While community awareness programs aim to increase recognition of symptoms and encourage people to seek medical advice, there is evidence that people delay seeking medical attention for reasons including a perceived lack of urgency about symptoms and stigma associated with lung pathologies if they have been smokers.19 Another reason for emergency presentation could be referral to an emergency department, either by a physician or patient self-referral, as a way to avoid real or perceived waiting time, financial or distance barriers to accessing a lung specialist or diagnostic procedures in the community.20,21

It is difficult to compare our pathway results with other studies because of differences in data sources, methods and health systems. The proportion of people diagnosed following an emergency presentation in this study (25%) is lower than the figure of around one third reported in two other Australian studies and 39% in a UK study but much higher than the 6% in a Danish study.9,22,23,24 Although NSW emergency department data contains coded diagnostic information, these codes often reflect the presenting symptoms rather than the underlying diagnosis. The emergency department codes are assigned by a range of emergency department staff, whereas diagnoses in the NSW hospital data are coded by specialist medical coders using the medical record for each admission. Since people presenting to emergency departments who are diagnosed with lung cancer are likely to be admitted, we defined an emergency diagnosis pathway as one with an emergency hospital admission with a lung cancer diagnosis in order to avoid capturing people presenting to emergency departments who do not receive a definitive diagnosis. Another difference between studies is the definition of lung specialist. In the absence of information on lung cancer MDT membership, we included respiratory physicians and cardiothoracic surgeons, although some studies also include medical and radiation oncologists as lung specialists.4,5,7

A limitation of the data is that they do not contain presenting symptoms at GP and specialist attendances or imaging results. This meant that we were unable to calculate time intervals between first presentation with lung symptoms and diagnosis or treatment, assess the appropriateness of the observed pathways compared to a clinical guideline or standard, or identify people diagnosed incidentally. Although in our study health service use was similar across cities and rural areas in the lead-up to diagnosis, there may be disparity in the time between first presentation with symptoms and accessing specialist and diagnostic services that we could not measure. We were unable to identify a diagnostic procedure for around a third of people with a histopathological diagnosis, consistent with known under-reporting of diagnostic procedures in the hospital admission data.25

Smoking prevalence is lower among 45 and Up Study participants and smoking is the most important lifestyle risk factor in people presenting with lung cancer.19,26 45 and Up Study participants diagnosed with lung cancer were less socio-economically disadvantaged, healthier and less likely to live in major cities than all NSW residents aged ≥45 years diagnosed with lung cancer.27 Hospital and emergency department use in the year prior to lung cancer diagnosis were similar between 45 and Up Study participants and all NSW residents; however, primary and outpatient care use could not be assessed.27 Participants of cohort studies may differ from non-responders in their health literacy and health-seeking behaviours. This may result in differences in diagnostic pathways compared with the general NSW population with lung cancer.

Studies of diagnostic pathways are often based on patient medical record reviews, surveys or interviews and are restricted to small geographic areas or a limited number of hospitals.9,10,11 A strength of this study is that linkage of health-related records for 45 and Up Study participants enabled the examination of the use of primary care, outpatient imaging, specialist care and admissions to hospital in the lead-up to diagnosis of lung cancer for a NSW-wide sample using data with population-level coverage, which had previously been a gap in understanding care pathways for lung cancer.

The Australian Optimal Care Pathway (endorsed in 2015) lays out expected pathways of initial investigations, referral, diagnosis and treatment for people presenting with suspected lung cancer with the aim of promoting best practice care regardless of where people live or have treatment.28 Our study focussed on GP-ordered imaging and specialist referral, which are steps laid out in the Optimal Care Pathway. The optimal pathway for a person with suspected lung cancer will depend on their presenting signs and symptoms and may include GP-referred imaging, referral to a specialist who is part of an MDT and referral of those with massive haemoptysis or stridor to the emergency department. Our study period is before the publication of the Optimal Care Pathway but can provide baseline data on health service use. Some areas in NSW have implemented localised optimal care pathways using GP decision aid software that provides management guidelines for people presenting with respiratory symptoms and referral details for lung specialists who are MDT members and for rapid access clinics. This implementation at a local level should assist with ensuring that people presenting with symptoms receive appropriate investigations in a timely way.

This study revealed that more than half of people did not attend a lung specialist in the diagnostic pathway of NSCLC. A quarter of people diagnosed presented as emergencies and more than half of those had no prior evidence of GP or lung specialist involvement in their diagnostic work-up. This study also highlights the key role that GPs have in the diagnosis of lung cancer. Ensuring that GPs have information available to them to initiate appropriate investigations and referral to specialists who are members of lung cancer MDTs has the potential to promote best practice care for people with lung cancer. Further research on barriers to recognition of lung cancer symptoms and access to lung specialists is needed from both a patient and physician perspective.